distinguishing between source areas of lacustrine ... · while higher land plants (phylum...
TRANSCRIPT
FACULTEIT WETENSCHAPPEN
Opleiding Master of Science in de geologie
Academiejaar 2015–2016
Scriptie voorgelegd tot het behalen van de graad Van Master of Science in de geologie
Promotors: Dr. M. Van Daele, Prof. Dr. S. Bertrand Leescommissie: Dr. Inka Meyer, Prof. Dr. Jasper Moernaut
Distinguishing between source areas of lacustrine
turbidites triggered by the 1960 and 2010 great Chilean earthquakes
Nick Kiekens
Cover picture: View on the Guacho river delta, draining water from the Villarrica Volcano
(background) into Lake Calafquén (Photo by Andrés García Prieto).
ACKNOWLEDGEMENTS
To start off, I would like to express my greatest thanks to both my promotors, Prof. Dr. Sébastien
Bertrand and Dr. Maarten Van Daele, for giving me the chance to perform my MSc. thesis on such a
fascinating subject. Furthermore, I would like to thank them for their amazing guidance throughout
the whole project and their major effort on reading, correcting and rereading the manuscript, even
when they were out of office.
I would also like to thank Elke Vandekerkhove for providing me with numerous papers on types and
characteristics of lacustrine turbidites, and together with Zakaria Ghazoui for the tips and tricks on
preparing the samples for carbon and nitrogen analysis.
I would also like to express my gratitude to the whole staff of the Renard Centre of Marine Geology
for the usage of the equipment at their sedimentology lab (Dep. of Geology, Ghent University) and
for their introductory software classes on Grapher, Strater and CorelDraw, saving me a lot of time
figuring out how each program works. Thanks also go out to the staff of the marine biology lab (Dep.
of Geology, Ghent University), who let me use their equipment during sample preparation.
Special thanks to the Stable Isotope Facility of the University of California, Davis for carrying out the
carbon and nitrogen analyses as soon as possible and reducing the turnaround times for both sample
series.
Last but not least, I would like to thank my family and friends for their endless support and patience
during the more stressful times I encountered while finishing up this thesis.
Thank you all and enjoy reading!
TABLE OF CONTENTS
1. Introduction ........................................................................................................................................................ 1
2. Setting ................................................................................................................................................................. 3
2.1 Geomorphological setting ............................................................................................................................ 3
2.2 Seismotectonic context ................................................................................................................................ 3
2.3 Climatic context ............................................................................................................................................ 5
2.4 Lake setting ................................................................................................................................................... 5
2.4.1 Lake Villarrica ........................................................................................................................................ 6
2.4.2 Lake Calafquén ...................................................................................................................................... 7
2.4.3 Lake Riñihue .......................................................................................................................................... 7
2.4.4 Lake Rupanco ........................................................................................................................................ 8
2.4.5 Sedimentation ....................................................................................................................................... 8
3. Lacustrine turbidites ......................................................................................................................................... 11
3.1 Discriminating source areas ........................................................................................................................ 11
3.1.1 Bulk organic geochemistry .................................................................................................................. 11
3.1.2 Sediment grain size ............................................................................................................................. 14
3.2 Deposit types .............................................................................................................................................. 16
3.3 Reports and turbidite descriptions ............................................................................................................. 17
3.3.1 Lake Villarrica: VI4, VI8, VI18 ............................................................................................................... 17
3.3.2 Lake Calafquén: CGC1, CB4, CB9, CALA05, CALA08 ............................................................................. 18
3.3.3 Lake Riñihue: RI5, RI7, RI8 ................................................................................................................... 19
3.3.4 Lake Rupanco: RUP02BIS, RUP03TRIS, RUP04..................................................................................... 21
4. Material and Methods ...................................................................................................................................... 22
4.1 Sediment cores and sampling ..................................................................................................................... 22
4.2 Sample preparation .................................................................................................................................... 23
4.3 Loss on ignition ........................................................................................................................................... 23
4.4 Carbon and nitrogen elemental and isotopic analysis ................................................................................ 23
4.7.1 Sample preparation ............................................................................................................................. 23
4.7.2 Analysis at UC Davis Stable Isotope Facility ........................................................................................ 24
4.8 Grain size analysis ....................................................................................................................................... 25
4.8.1 Sample preparation ............................................................................................................................. 25
4.8.2 Analysis with Malvern Mastersizer ...................................................................................................... 25
5. Results ............................................................................................................................................................... 27
5.1 Lake Villarrica .............................................................................................................................................. 27
5.1.1 VI4........................................................................................................................................................ 27
5.1.2 VI8........................................................................................................................................................ 27
5.1.3 VI18...................................................................................................................................................... 28
5.2 Lake Calafquén ............................................................................................................................................ 30
5.2.1 CGC1 .................................................................................................................................................... 30
5.2.2 CB4 ...................................................................................................................................................... 31
5.2.3 CB9 ...................................................................................................................................................... 31
5.2.4 CALA05 ................................................................................................................................................ 32
5.2.5 CALA08 ................................................................................................................................................ 33
5.3 Lake Riñihue ................................................................................................................................................ 35
5.3.1 RI5 ........................................................................................................................................................ 35
5.3.2 RI7 ........................................................................................................................................................ 36
5.3.3 RI8 ........................................................................................................................................................ 37
5.4 Lake Rupanco .............................................................................................................................................. 38
5.4.1 RUP02BIS ............................................................................................................................................. 38
5.4.2 RUP03TRIS ........................................................................................................................................... 39
5.4.3 RUP04 .................................................................................................................................................. 40
6. Discussion .......................................................................................................................................................... 43
6.1 Correlation between LOI550 and TOC .......................................................................................................... 43
6.2 Relation between C/N atomic ratio and grain size ..................................................................................... 45
6.3 Interpretation C/N atomic ratio and grain size ........................................................................................... 47
6.3.1 Lake Villarrica ...................................................................................................................................... 47
6.3.2 Lake Calafquén .................................................................................................................................... 50
6.3.3 Lake Riñihue ........................................................................................................................................ 52
6.3.4 Lake Rupanco ...................................................................................................................................... 54
6.4 Potential of C/N .......................................................................................................................................... 55
7. Conclusions ....................................................................................................................................................... 56
8. References ......................................................................................................................................................... 57
9. Nederlandstalige samenvatting ........................................................................................................................ 65
10. Appendix ......................................................................................................................................................... 69
1
1. INTRODUCTION
Understanding the source area of turbidites in lacustrine settings can improve interpretation of
sediment cores and may aid in reconstructing slope failure processes or in comprehending the events
responsible for the sediment deformation, such as earthquakes and floods. Many studies have
already shown the potential, where records of turbidites and subaquatic landslides were used as an
archive for reconstructing the paleo-earthquake history in different tectonic settings (e.g.,
Schnellmann et al., 2002; Migowski et al., 2004; Moernaut et al., 2007; Beck, 2009; Waldmann et al.,
2011; Smith et al., 2013) and for modelling historical flood events during periods of high fluvial
discharge (e.g., Czymzik et al., 2010; Wilhelm et al., 2012; Saitoh and Masuda et al 2013; Simonneau
et al., 2013; Wilhelm et al., 2013).
In this thesis, the carbon-to-nitrogen (C/N) ratio is used as an alternative parameter to distinguish
between the source areas of a series of turbidites from four different lakes in the Chilean Lake
District (39°S-41°S), located in similar climate zones and with comparable morphological and
limnological characteristics (Campos, 1984). These turbidites were simultaneously triggered by the
1960 Valdivia and 2010 Maule megathrust earthquakes along the Nazca-South American plate
boundary. Well recorded eyewitness reports of the seismically-induced events (e.g., onshore
landslides, mudflows, small-scale lake tsunamis, seiches, subsidence, absence of events) in and
around the lake were used to compare core data and improve interpretation.
The C/N ratio represents the atomic ratio of organic carbon to that of nitrogen in a sample. It is
widely and often used as a parameter in the analysis of sediment cores, and its most well-known
application may be as a proxy in paleoclimate research. It is mainly utilised in lacustrine sediment
cores, since organic material found in marine sediments holds information about the source before
reaching the floor as well as after burial, next to the processes it was subjected to (Jasper and
Gagosian, 1990; Meyers, 1994; Prahl et al., 1994). Algae in general have a C/N ratio of about 4 to 8,
while higher land plants (phylum Tracheophyta) have C/N ratios of ≥ 20 (Premuzic et al., 1982; Jasper
and Gagosian, 1990; Meyers, 1994; Prahl et al., 1994). In the Ocean, Emerson and Hedges (2003)
observed that about 90 % of the organic matter produced at the surface is being degraded by
bacteria while moving down the water column. After burial, sediment diagenesis degrades another 9
% of the organic carbon that sinks to the deep ocean floor, so that eventually only 1 % is permanently
buried in the sediment. For lacustrine sediments on the other hand, sediment diagenesis does not
have such an impact on the organic matter. Organic carbon isotope ratios do not seem to display
significant diagenetic shifts. In a study by Rea et al. (1980) in Lake Michigan for example, δ13C values
remained at 26‰ from modern to 3500-year old sediments in which organic carbon concentrations
varied between 1 and 3%. Diagenesis also doesn’t have an impact on the integrity of the C/N ratio
(Meyers and Ishiwatari, 1993). The change in elemental composition upon burial is not large enough
to remove the vascular/non-vascular plant signals and this due to the refractory nature of terrestrial
organic matter (Meyers and Ishiwatari, 1993; Meyers, 1994). Therefore shifts in the C/N ratio in a
lacustrine sediment core can be interpreted as shifts in the organic source material, whether the
organic carbon found in the sediment comes from land-based plants or rather has an algal origin
(Ishiwatari and Uzaki, 1987). Furthermore, this ratio can be used to differentiate between certain
groups of land-based plants, depending on the kind of carbon fixation pathway they follow (e.g., C3
2
and C4 plants). This makes it a useful tool for determining the source areas of organic matter in
sediments. A more elaborated explanation can be found in section 3.1.1.
With this in mind, the goal of this thesis is to study to which extent the C/N ratio can be used to
differentiate between source areas of lacustrine turbidites, such as hemipelagic slope failures, river-
delta failure, onshore landslides surging directly into the lake, flood related events, mud flows, etc. A
next step is to assess if there is any relation to the grain size distribution, as often the C/N ratio is
closely related to the grain size of the clastic component of the sediment (Howarth et al., 2014).
Eventually, if sediment-based data and historical reports show a consistent degree of correlation, it
can be used as a proxy for long cores in future lacustrine paleo-seismic/-climate research.
In order to find an answer to these questions, 18 turbidites of known origin were sampled from a
series of cores taken in different sedimentary environments in the lakes, which were collected during
two separate field expeditions in 2009 and 2010. Samples were first prepared for the loss on ignition
method, so the total organic carbon content could be estimated for subsequent carbon and nitrogen
elemental and isotopic analysis preparation. In parallel, another identical series of samples were pre-
treated for grain size analysis. Finally, the carbon-to-nitrogen ratios of all samples were compared to
the delta values of 13C and to the mean grain size distributions, to determine the source of the
sedimentary organic matter and to find a correlation between both, respectively.
3
2. SETTING
2.1 GEOMORPHOLOGICAL SETTING
The study area is situated in south-central Chile and is focused on four large lakes in the Chilean Lake
District. From north to south (Fig 1) there is Lake Villarrica (39.25°S), located about 700 km south of
the capital Santiago in the Araucanía Region, followed by Lake Calafquén (39.52°S), Lake Riñihue
(39.80°S) and Lake Rupanco (40.82°S). The latter is located about 175 km south of Lake Villarrica and
80 km north of the port city Puerto Montt in the Los Lagos Region. Four basic geomorphological
zones can be distinguished from west to east: the Coastal Range (Cordillera de la Costa), the
Intermediate Depression (Central Valley), the Precordillera and the Andean Cordillera (Fig. 1). All four
studied lakes are positioned along a narrow band at the foot of the Andes, as a part of the
Precordillera. The Intermediate Depression is separated from the Coastal Range and the Andean
Cordillera due to a series of faults running north to south and shows a trend of decreasing altitude
towards the south. Around the latitude of Lonconche (39.37°S), the Intermediate Depression is
locally absent due to the eastward extension of the Coastal Range by the Bahía Mansa Metamorphic
Complex, making up a terrain of harder pelitic schists, metagreywackes and oceanic type mafic
metavolcanics (Duhart et al., 2001). The geomorphological units are oriented parallel to the coast
and the subduction zone.
2.2 SEISMOTECTONIC CONTEXT
Tectonic processes in this region are a consequence of the ongoing oblique subduction of the Nazca
Plate underneath the South American Plate along the Peru-Chile Trench. The Nazca Plate is bounded
on the west by the Pacific Plate and to the south by the Antarctic Plate through the East Pacific Rise
and the Chile Rise, respectively. The Nazca plate moves slightly east-northeast, relative to a
stationary South American Plate, at a convergence rate varying from approximately 80 mm/yr in the
south to approximately 70 mm/yr in the north with an average rate between these two plates
estimated at 73.7 mm/yr (DeMets et al., 2010), which is among the highest worldwide. This
subduction zone is geologically complex and generates a large number of earthquakes due to a
variety of tectonic processes. Shallow earthquakes are a result of crustal deformation and
subsequent mountain building in the overriding South American Plate, while the large interplate
earthquakes are produced by a slip along the dipping interface of the subducting plate at depths up
to 60 km (Comte and Suárez, 1995). A part of the stress from the oblique subduction is relieved along
the 1000 km long Liquiñe-Ofqui Fault Zone, running along the Andean Cordillera in proximity of the
studied lakes. It is dextral strike-slip lineament, separating the north-moving Chiloé sliver (6.5 mm/yr
south of Puerto Montt) from the rest of the South American Plate (Cembrano et al., 2000; Wang et
al., 2007; Melnick et al., 2009).
Since the 20th century, numerous magnitude 8 or greater earthquakes have occurred on the interface
between the Nazca and South American plates. On May 22nd 1960, the great Chilean earthquake with
a Mw 9.5 took place in southern Chile along the Valdivia seismotectonic segment (Métois et al.,
2012). This earthquake is currently the largest instrumentally recorded earthquake in the world, with
4
Fig. 1. Setting study area in South-Central Chile with map detail of the studied lakes. Epicentres, magnitudes
and local seismic intensities for the 1960 and 2010 main events are marked in red and blue, respectively.
1960a: 21 May foreshock; 1960b: 22 May main event. Coseismic slip area (> 5 m) for the main 1960 and 2010
events after Moreno et al. (2009, 2012). Geomorphology and tectonic structures: CR, Coastal Range; ID,
Intermediate Depression; AC, Andean Cordillera; A-N, Arauco Peninsula-Nahuelbuta Range; MS, Maule
segment; VS, Valdivia segment; LOFZ, Liquiñe-Ofqui Fault Zone. Volcanoes part of the sediment catchment of
the respective lakes are marked on the map detail. Adapted from Van Daele et al. (2015)
a rupture length from Lebu to Puerto Aisen of around 1000 km (Cifuentes, 1989). On the Modified
Mercalli (MM) Intensity Scale, Lake Calafquén reached the highest intensities of the studied lakes
5
with an intensity VIII (‘Severe’), while the other studied lakes were estimated at VII½ (‘Very strong’;
Lazo, 2008; Van Daele et al., 2015). However, macroseismic intensities in different areas of the
affected region can vary greatly depending on the type of soil, where tectonically depressed areas
suffered heavier damage (Weishet, 1963). Hence, estimations that are made based on observed
infrastructural damage should be looked at carefully. Numerous landslides were triggered, mainly on
the steeper valley flanks of the Andes (Tazieff, 1960; Wright and Mella, 1963; Weishet, 1963), some
resulting as turbidites in lakes downstream/-slope of the landslides (Van Daele et al., 2015).
Especially the area of the studied lakes was hit by many onshore landslides. A probable cause for this
local concentration of landslides may be due to the proximity to the Liquiñe-Ofqui Fault Zone. The
fractured substrate in this area together with the presence of active volcanoes, which have formed
thick and unconsolidated pyroclastic deposits, makes it prone to landslides (Weishet, 1963). A
potential disaster was narrowly avoided as a landslide near the Tralcan Mount dammed the outflow
of Lake Riñihue, resulting in a water level rise of 26 m, dangerously increasing pressure on the river
dam downstream (Weishet, 1963). Other phenomena such as lake tsunamis and related seiches,
were also observed in neighbouring lakes, e.g. Lake Rupanco (Weishet, 1963; Wright and Mella,
1963).
On February 27th 2010, another large megathrust earthquake occurred with a Mw 8.8 and a rupture
length of 500-600 km, closing a seismic gap on the Maule segment that had not experienced a large
megathrust earthquake since 1835 (Métois et al., 2012), just north of the Valdivia segment (Moreno
et al., 2012). Macroseismic intensities for lakes Villarrica, Calafquén, Riñihue and Rupanco are
estimated VI (‘strong’), V½, V (‘moderate’) and IV½ (light) respectively on the MM Intensity Scale,
according to U.S. Geological Survey (2016) ShakeMaps. The 1960 and 2010 events are the most
significant, but numerous other earthquakes struck the study area during the past century. These
involve major foreshocks and aftershocks of the 1960 and 2010 main events, as well as dozens of
other interplate earthquakes (Van Daele et al., 2015), but in this study the focus lies on the deposits
of the 1960 and 2010 megathrust earthquakes.
2.3 CLIMATIC CONTEXT
The climate in this region is humid-temperate with mainly heavy rainfall during austral winter.
Summers are cool due to cool ocean currents, while winters are milder than other climates in similar
latitudes. Precipitation is driven by strong southern Westerlies, known colloquially as the “roaring
forties”, and is slightly reduced during El Niño years (Heusser, 2003). Vegetation is heavily influenced
by the Westerlies. The polar Pacific air becomes unstable as it cools and condenses on crossing the
Cordillera de la Costa and on rising up the west slope of the Andean Cordillera, providing a lot of rain
along these regions (Heusser, 1974).
2.4 LAKE SETTING
Lakes Villarrica, Calafquén, Riñihue and Rupanco (Fig. 1) are located in the northern half of the
Valdivia segment between 39°S and 41°S. They fall within a similar temperate rainy climate zone,
with or without a dry season. Vegetation’s carbon fixation type in this region is dominated by C3
carbon fixation, rather than C4. The reasoning behind this statement is that C4 plants (e.g. Cyperus
rotundus, Cynodon dactylon, Eleusine indica) are more efficient in photosynthesis under hot, sunny,
6
dry conditions, but not under more temperate, moist conditions (Heusser, 1974; Sage et al., 1999b).
Therefore C3 plants are far more abundant in wetter, more temperate environments, as is the case
for the study area. The type of carbon fixation utilised by the lake’s surrounding vegetation is an
important parameter in the interpretation of C/N results, but more on this subject can be found in
the methods section (section 3.3.1).
All four studied lakes show comparable morphological and limnological characteristics (Campos,
1984). The lake basins originate from glacial valley overdeepening during the Late Quaternary
glaciations (Laugenie, 1982). They are all positioned at the western foot of the Andean Cordillera and
dammed by a series of frontal moraines (Laugenie, 1982; Bentley, 1997). The overall bottom
morphologies are characterized by a central deep basin and shallower areas in the western parts
where several sub-basins, bedrock mounds, and moraine ridges are located (Moernaut, 2010; Van
Daele et al., 2014b). The major river inflows are situated on their eastern boundary, where the
coarsest fraction of their sedimentary load is deposited in the associated deltaic fans and in the
proximal, deep basins through underflows (Moernaut et al., 2014). Their outflow is located at their
western limits with the exception of Lake Calafquén, where the main outflow is situated east of its
center. Important to note is that the lakes Calafquén and Riñihue are indirectly connected with each
other through riverine systems and several other lakes. This has an impact on the sediment
catchment area of each lake since they work as a sediment trap and thus reduce the sediment supply
for the lakes downstream. A more detailed description of each lake’s characteristics can be found in
the next paragraphs.
2.4.1 LAKE VILLARRICA
Lake Villarrica is located 215 m a.s.l. and stretches over a surface area of 174 km² (Table 1). It consists
of a single central basin with a maximum depth of 167 m, with some shallower areas with more
morphological variability in the southwestern part of the lake (SHOA, 1987). Vegetation in the lake’s
surrounding area is dominated by a deciduous forest, with a transition to a more temperate
evergreen macrobioclimate (Moreira-Muñoz, 2011). Deciduous broadleaved species such as of the
Nothofagus (e.g. N. alessandrii, N. glauca) and Eucalyptus are abundant, mixed with evergreen
coniferous trees such as those of the genera Araucaria, Laurelia, and Eucryphia (San Martín and
Donoso, 1996). Undergrowth mostly exists of myrtaceous shrubs (e.g. Myrceugenella and
Myrceugenia), along with genera like Rhaphithamnus, and Azara, and a variety of epiphytes (e.g.
Luzuriaga radicans, Sarmienta repens, Hydrangea; Heusser, 1974). This rather dense vegetation
together with the high amount of precipitation during austral winter suggests that the availability of
easily erodible material in the sediment catchment is the controlling factor in sediment transport to
the lakes (Van Daele et al., 2014). Lake Villarrica has a sediment catchment area of 2650 km²
(Moernaut et al., 2009), which is by far the largest of the four studied lakes. The sediment catchment
comprises the northern slopes of Villarrica, Quetrupillán, and Lanín (Van Daele et al., 2014). The
Trancura River in its eastern extremity is the major river inflow and supplier of sediments in Lake
Villarrica. On average, the sedimentation rate is determined at 1.5 mm/yr in the western sub-basins
(Van Daele et al., 2014; Moernaut et al., 2014). The Toltén River in the lake’s western extremity
cross-cuts the moraine ridges and regulates the outflow of the lake towards the Pacific Ocean.
7
2.4.2 LAKE CALAFQUÉN
Lake Calafquén is located 204 m a.s.l. and extends over an area of 118 km² (Table 1). It exists of a
large, deep basin with a maximum depth of 215 m depth, with a smaller sub‐basin situated in the
southwestern part of the lake (SHOA, 2008). The climate and vegetation in this area is nearly
identical to the one seen near Lake Villarrica, since they are in close proximity to one another (in
straight line ca. 30 km). A subtle increase in transition to a more temperate climate vegetation with
mixed forests might be observed, where evergreen angiosperm trees next to their deciduous
specimens, as well as evergreen conifer trees, are more common. The catchment area of Lake
Calafquén is 554 km² (Moernaut et al, 2009) and significantly smaller than the one observed in the
nearby Lake Villarrica. The catchment consists of the southern slopes of Villarrica Volcano and the
southwestern slopes of Quetrupillán Volcano (Van Daele et al., 2014). The main tributary of the Lake
is the Llancahue River. An average sedimentation rate of 1 mm/yr was determined by Van Daele et
al. (2014) and Moernaut et al. (2014) in the southwestern sub-basins. The outflow of the lake is
controlled by the Pullinque River, leading to the Pullinque Lake.
2.4.3 LAKE RIÑIHUE
Lake Riñihue is situated 107 m a.s.l. and has a surface area of 90 km² (Table 1). It consists of a central
basin with a depth up to 323 m and two western sub-basins (Campos et al., 1987). The area of
interest for this lake lies in its more shallow western section, where Riñihue is cut into two arms by
the Tralcán Mount. The same climate classification applies for the region around Lake Riñihue as for
the previously discussed lakes, which is an oceanic temperate rainy climate were precipitation
dominates during austral winter. The vegetation in the catchment can be classified as a Valdivian
temperate (rain)forest. The forest is characterised by broadleaf tree species with evergreen, glossy
and elongated leaves, mostly dominated by plants from the Lauraceae family and hence its other
denomination as laurisilva. Some of its components are Aextoxicon punctatum, Laureliopsis
philippiana, Dasyphyllum diacanthoides, Luma apiculate, Laurelia sempervirens, Eucryphia cordifolia
and Weinmannia trichosperma intermixed with Nothofagus species (Moreira-Muñoz, 2011). The
sediment catchment area of the lake is 382 km² (Van Daele et al., 2015), which is rather small
compared to the other three lakes in this study. The reason for this is because it is the last basin in
the Seven Lakes chain (Fig. 2). Lake Riñihue receives indirectly the water from the lakes Pellaifa,
Calafquén, Pullinque, Panguipulli, Neltume and Pirihueico through riverine systems. All these lakes
function as sediment traps, resulting in a relatively small sediment catchment. The primary source
area for the detrital fraction of the sediment in this lake is the western flank of Mocho-Choshuenco
Volcano (Laugenie, 1982). However, the elongated shape of the lake, and thus the relative proximity
to the coastline of each location in the lake, makes the slopes bordering the coastline also important
sediment suppliers. The main contributor to its water and sediment supply is the Enco River on its
eastern side. A sedimentation rate of 1 mm/yr was calculated by Moernaut et al. (2014) for the
western sub-basins. The San Pedro River in its northwestern extremity is the outflow, draining the
water from the lake to the Pacific Ocean.
8
Fig. 2. Structural image of the Seven Lakes’ hydrographic network.
2.4.4 LAKE RUPANCO
Lake Rupanco is located 123 m a.s.l. and has the largest surface of all four lakes, with an area
extending over 231 km² (Table 1). It exists of a central basin reaching depths up to 269 m below lake
level, and an eastern, southern and western sub-basin (SHOA, 2001). Climate conditions and
vegetation change as the latitude shifts approximately one degree southwards in comparison with
previously discussed Lake Riñihue. A temperate rainy climate still reigns these regions, but with
significant precipitation during all seasons. Vegetation can be classified as a North Patagonian
rainforest with predominantly evergreen species such as those of the broadleaf Nothofagaceae (e.g.
Nothofagus dombey, N. nitida, N. betuloides) and conifers from the Podocarpaceae (e.g. Podocarpus
nubigenus; di Castri and Hajek, 1976). Epiphytes densely cover trunks and branches and include
species such as Griselinia scandens, Pseudopanax laetevirens, Asteranthera ovata, Philesia
naagellanica, Mitraria coccinea, and a variety of filmy ferns (e.g. Hymenophyllum) and mosses.
Shrubs (e.g. Lomatia ferruginea, Maytenus magellanica) are less abundant (Heusser, 1974). The
sediment catchment of Lake Rupanco has an area of 629 km² (Van Daele et al., 2015). It comprises
the northern flank slopes of the Puntiagudo Volcano and the western flank slopes of the Casablanca
Volcano. The main tributaries to the lake consist of the Gaviotas River and the Bonito River. Van
Daele et al. (2015) calculated an annual sedimentation rate between 1.1 to 2.85 mm. The outflow of
Lake Rupanco is the Rahue River, which is located in its western extremity.
2.4.5 SEDIMENTATION
The hemipelagic sedimentation of all four lakes has been classified as a diatomaceous ooze with a
small fraction of terrestrial organic matter, dispersed volcanic ash, and terrigenous clays/silts (Van
Daele et al., 2014; Van Daele et al., 2015). Sedimentary sequences in general show annually
deposited µm- to mm-scale laminations (i.e. varves; Boës and Fagel, 2008; Van Daele et al., 2014;
Van Daele et al., 2015). The varved lake sediments consist of laminae of organic-rich clayey to silty
terrestrial material deposited during increased winter river discharge and a lamina largely built of
diatom frustules deposited in spring, when bloom of diatoms occurs due to winter turn-over
(Moernaut et al., 2014). This depositional cycle has been broadly studied in the nearby Lake Puyehue
(40.68°S) by Boës and Fagel (2008). Lakes Villarrica and Calafquén also show the occurrence of lahars
during eruptions of the Villarrica Volcano. These mudflows contribute significantly to the sediment
budget of the deep proximal basins and can leave thin, fine-grained deposits with a terrestrial
composition in the more distal and shallower areas of the lakes (Van Daele et al., 2014). Tephra
9
layers, varve counts and 210Pb/137Cs radionuclide dating were used to construct accurate age-depth
models for the lakes Villarrica, Calafquén, Riñihue and Rupanco (Van Daele et al., 2014; Moernaut et
al., 2014; Van Daele et al., 2015). These were used to determine the timing of events causing
observed lacustrine turbidites, so distinction could be made between turbidites of the 1960 and 2010
great Chilean earthquakes.
10
Table 1. General information on setting, bathymetry, climate, vegetation and sedimentation rates for all studied lakes. *Sedimentation rates determined from master cores
VILLSC01 (Villarrica), CAGC02bis (Calafaquén) and RINGC03 (Riñihue). See Figure 4 and 5 for location. Adapted from Van Daele et al. (2015)
Lake Latitude (°S)
Longitude (°W)
Altitude (m a.s.l.)
Lake surface (km²)
Catchment area (km²)
Catch./lake ratio
Max. depth (m)
Bathymetry source
Climate (Köppen–Geiger class.)
Vegetation Sediment. rate (mm/yr)
Sediment. rate source
Villarrica 39.25 72.10 215 174 2287 13.1 167 SHOA (1987) + RS (Moernaut et al., 2014)
Temperate rainy (Cfs)
Deciduous forest
ca. 1.5 * Van Daele et al. (2014a,b); Moernaut et al. (2014)
Calafquén 39.52 72.18 204 118 555 4.7 212 SHOA (2008) + RS (Moernaut et al., 2014)
Temperate rainy (Cfs)
Deciduous forest
ca. 1 * Van Daele et al. (2014a,b); Moernaut et al. (2014)
Riñihue 39.80 72.38 107 90 382 4.3 323 Campos et al. (1987) + RS (Moernaut et al., 2014)
Temperate rainy (Cfs)
Valdivian rainforest
ca. 1 * Moernaut et al. (2014)
Rupanco 40.82 72.50 123 231 629 3.0 269 SHOA (2001) Temperate rainy, without dry season (Cfb-c)
N. Patagonion forest
1.1-2.85 Van Daele et al. (2015)
Fig. 2. Slope-shaded SRTM map of Lake Riñihue & Lake Rupanco and their surrounding area with onshore reports, local seismic intensities, bathymetry, SEDs and coring
locations. Used cores in this thesis are marked orange. Adapted from Van Daele et al. (2015)
11
3. LACUSTRINE TURBIDITES
Lake turbidites have already proven their importance as a tool for understanding sedimentary
sequences and attributing a certain tectonic and depositional event to its origin, as they require at
least a subaquatic slope and some sort of gravity process (loading), tectonism or other extreme event
to trigger density-based (hyperpycnal) currents (e.g., Monecke et al., 2004; Strasser et al., 2006;
Howarth et al., 2012 and 2014; Moernaut et al., 2014). The sediment archives containing these
rapidly deposited layers can represent a high resolution record of seismicity and terrestrial flood
events, depending on the supply of (terrestrial) sediment sources (Goldfinger et al., 2012).
Furthermore, they can provide chronologic evidence of the frequency of landslides and the
earthquakes that probably triggered them by using radiocarbon dating or varve counting above and
below the turbidite (Strasser et al., 2006; Moernaut et al., 2007; Enkin et al., 2013).
3.1 DISCRIMINATING SOURCE AREAS
3.1.1 BULK ORGANIC GEOCHEMISTRY
As palaeo-environmental and source information are preserved in the molecular, elemental and
isotopic compositions of organic matter, C/N ratios have often been used to differentiate between
algal and land plant origins in sedimentary organic matter (Prahl et al., 1980; Premuzic et al., 1982;
Ishiwatari and Uzaki, 1987; Jasper and Gagosian, 1990). Marine and lacustrine algae typically have
atomic C/N ratios in the range of 4 to 8 (Redfield ratio), in contrary to the vascular land plants, which
have C/N ratios of ≥ 20. The contrast arises due to compositional differences in the organic matter
produced by both groups. Aquatic algae are typically protein-rich and cellulose-poor, while vascular
land plants are protein-poor and cellulose-rich. These nitrogen-rich proteins together with the lack of
carbon-rich cellulose are responsible for the relative lower C/N ratios for aquatic algae and vice versa
for the relative higher C/N ratios in vascular plants.
Carbon isotope ratios have already been proven useful to distinguish between marine and
continental plant sources of organic matter in sediments and to identify the different source types of
land plants (e.g., Hunt, 1970; Newman et al., 1973; Gearing et al., 1977; Prahl et al., 1980; Premuzic
et al., 1982). Higher land plants can be subdivided into 4 major groups based on their type of carbon
assimilation. Most photosynthetic plants incorporate carbon following the C3 carbon fixation (Calvin
pathway), which biochemically prefers incorporation of 12C to produce a δ13C shift of -20 ‰ from the
isotope ratio of the inorganic carbon source (Meyers, 1994). They comprise about 85 % of all
terrestrial plant species (Simpson, 2010) and include most trees and small seeded cereal crops. Some
plants use the C4 carbon fixation (Hatch-Slack pathway). Here carbon is fixed that is significantly
enriched in 13C, which creates a diffusional isotope shift of -7 ‰ (Meyers, 1994). Only about 3 % of all
plant species are thought to employ a C4 carbon fixation, of which mostly grasses and sedges
(Simpson, 2010). Another group comprising 8 % of all terrestrial plants uses the Crassulacean acid
metabolism (CAM; Simpson, 2010). This type of carbon fixation was developed as an adaptation for
dry, desert habitats. The residual 4 % does not use oxygenic photosynthesis to fix carbon in their
structure, but relies on a heterotrophic lifestyle (e.g. symbiotic, parasitic) where carbon is not fixed,
but rather used for growth. However, CAM plants and the residual heterotrophic plants are not of
importance in this study and will not be mentioned further throughout this thesis. Organic matter
12
produced from atmospheric CO2 (δ13C ≈ -7 ‰) by land plants following the C3 pathway consequently
is in the δ13C-range of -30 to -25 ‰, with an average of -27 ‰, and by those following the C4 pathway
between -15 to -10 ‰, with an average of -14 ‰ (Fig. 3; O'Leary, 1988).
Fig. 3. Representative elemental and carbon isotopic compositions of sedimentary organic matter from
lacustrine algae, C3 land plants and C4 land plants that use carbon fixation during photosynthesis. Adapted from
Meyers and Lallier-Vergés (1999)
In this thesis, the usefulness of the C/N ratio is tested for recognizing the source area of lacustrine
turbidites (e.g. reworked hemipelagic-slope sediments, terrestrial/deltaic source area). As the
analyses were executed on samples from lacustrine turbidites, originating from source areas with
both a composition similar to the laminated hemipelagic sediments or more terrestrial influenced,
we can expect δ13C-values in the range of -25 to -30 ‰ This range corresponds with values for all the
aquatic organic matter and land plants using the C3 carbon fixation. Since both lie in the same range,
δ13C-values won’t be of any use in the distinction of source areas. C/N ratios on the other hand are
the variable of interest. These will range between the end members of lacustrine algae (4 to 8) and C3
plants (≥ 20), depending on the influence of terrestrial material.
In a study by Simonneau et al. (2013) in Lake Ledro (southern Alps, Italy), a distinction is made
between turbidites triggered by earthquakes and flood events based on C/N and the hydrogen index
(HI). They have combined high-resolution seismic profiles and sediment cores from the lake’s
catchment area and the riverbed to assign different turbidites from the Holocene to a certain
triggering event, i.e. earthquakes and floods. Cores of the lake showed that background
sedimentation is laminated and exists of millimetric to inframillimetric couplets of discrete white
calcite layers and brown organic layers, typical of calcite varves (Lotter and Lemcke, 1999; Brauer et
al., 2008; Czymzik et al., 2010) reflecting summer (main eutrophication phase resulting in higher
diatom productivity) and winter (deposition of detrital and amorphous organic material). These
regular couplets are sporadically interrupted by two types of SEDs. On one hand, there are light-
13
coloured massive layers, on the other hand dark-coloured graded beds. Based on analysis of the
organic matter present in the background of the lake and riverbed samples, together with lake
sediment bulk density and grain size analysis, Simonneau et al. (2013) concluded that the light-
coloured layers are composed of a mixture of lacustrine sediments, containing mostly algal particles
similar to the ones observed in background sediments (low C/N), while the dark-coloured layers
mainly consist of terrestrial organic matter from soils and land plants (high C/N), which is the same
organic signature as the samples taken in the watershed. In contrast to light-coloured, earthquake
triggered, turbidites, they usually do not contain a visible trace of hemipelagic background
sedimentation. These observations were confirmed by determining the HI values for both types of
SEDs. For the light-coloured layers these values (< 300 mgHC g−1 TOC) indicate that the organic
matter is more degraded than those in the background sediments. This suggests that these lighter
layers are made up of older reworked background sediments, which lead to their interpretation as
subaquatic mass-movements triggered by historical and pre-historical regional earthquakes. For the
dark-coloured SEDs in Lake Ledro, these HI values (<<< 300 mgHC g−1 TOC) suggest very little
maturation.
Previously discussed earthquake triggered turbidites all had a subaquatic sediment source, where
mainly background sediments were mobilised due to slope failure and subsequently redeposited. In a
study executed by Howarth et al. (2012) in Lake Paringa (South Island, New Zealand), a closer look is
taken at megaturbidite formation and turbidites resulting from hillslope landslides in the lake’s
catchment. A sedimentary sequence existing of a megaturbidite overlain by a series of smaller
turbidites was analysed. The megaturbidite contains a basal unit of normally graded fine sandy silt,
with above a layer of homogeneous very fine sandy silt, and a cap of medium silt. The fine sandy silt
base is explained as the deposition of a traction carpet, while the homogeneous very fine sandy silt
above was thought to be the result of material ejected into the water column settling down and
being reworked to the center of the basin by seiching. The medium silt cap is the eventual deposition
of the finest material that remained in suspension. Analysis of organic carbon and nitrogen content
showed a TOC = 3.5 % ± 1.9 % and C/N = 18.4 ± 2.8, which is in the range for mixed aquatic and
terrestrial sources (10-20; Meyers, 1997) and fits the interpretation of a lake delta slope failure.
The overlying stacks of as much as thirty turbidites have a basal unit of inversely graded very fine
sandy silt, gradually transitioning into a layer of normally graded medium silt, which is consistent
with the deposition from hyperpycnal flows formed from sediment-loaded flood deposits (Mulder
and Alexander, 2001). Also, these stacks of turbidites have a greater clastic sediment mass than all
other types of deposits encountered. Carbon and nitrogen elemental and isotopic analysis data
reports gave a TOC = 4.3 % ± 2.8 % and C/N = 29 ± 5 for the basal unit and a TOC = 3.8 % ± 2.0 % and
C/N = 22.3 ± 2.9 for the upper unit. The high sediment supply is interpreted as the result of
postseismic erosion of landslide debris in the catchment area, which is backed up by the high C/N
ratios of turbidite sediments, pointing to organic matter derived from land plants (> 20; Meyers,
1997).
Both deposits, the megaturbidite and the stacks of overlying turbidites, are seen as a part of a
repeating sequence in a seismic cycle. The megaturbidite’s sedimentology, thickness, and ponding
geometry is consistent with a coseismic deposition as a result of subaqueous mass wasting
accompanied by seiching (Beck, 2009; Schnellmann et al., 2002), followed by a postseismic landscape
14
response due to erosion. These sequences are topped by an aseismic, normal period of
sedimentation. This study from Howarth et al. (2012) gives valuable new insights in the duration and
magnitude of a postseismic response of a mountain landscape to large earthquakes, moreover, it
gives a first record of a postseismic response similar to successive large earthquakes.
Based on the tremendous number of aligned studies available today, it is safe to conclude that the
C/N atomic ratio is a very useful and valuable parameter in determining the source area of a
turbidite.
3.1.2 SEDIMENT GRAIN SIZE
Grain size trends in turbidites have also been used in the literature to determine their provenance,
therefore grain size analyses of all turbidites were conducted. In a first instance because grain size
distribution and variations throughout a turbidite may provide important information about the
origin (e.g. reworked hemipelagic sediment point to subaquatic slope failure; abundance in coarse
material may suggest delta failure or landslides; inverse grading may propose a flood event) and flow
conditions of a turbidity current. In a study by Mulder et al. (2001), the flow regimes responsible for a
classical fining-upward bed and a basal coarsening-upward unit are explained. They concluded that a
normally graded sequence represents a typical deposit of a decreasing flow (Komar, 1985; Kneller,
1995). Due to a continuous decline in flow energy with time and distance, a graded succession of
sedimentary facies (Ta, Tb, Tc, Td and Te) is deposited above a surface with often contrasting
sedimentation (e.g. hemipelagic sediments) and an erosive contact. This sharp basal contact is the
result from the erosive waxing head of the flow (Middleton and Hampton, 1973). The typical graded
deposit is called a Bouma sequence (Bouma, 1962). Ta-d describes the falling out of the coarse
fraction (Ta), followed by deposition of less coarse material (i.e. sand to coarse silt fraction) as the
energy of the turbidity current decreases and traction and saltation processes are not enough to
transport the sediment particles (Tb, Tc, Td). Te is the last layer deposited in a Bouma sequence. It
arises from the settling of the finest fraction in suspension (i.e. clay) where approximately no current
exists and represents deposition of the tail of the flow, intermixed with the ongoing normal
hemipelagic sedimentation. Absence of one or more facies within a Bouma sequence can be
attributed to the proximal or distal location to the observed event or due to the grain size of the
sediment transported in such current (e.g. lack of coarse material in source sediment). These
normally graded beds are the result of short-duration, unsteady hyperpycnal currents (Laval et al.,
1988). The sharpness of the basal contact, the intensity of erosion of the underlying deposits, and the
size of the transported grains depends on the energy of the event (Mulder and Alexander, 2001).
Beds with a basal coarsening-upward unit can have several origins. In a first case, mud clasts can be
incorporated in the base of a turbidite deposit. This will result in a local decrease in mean grain size
for the coarse fraction in a regular Bouma sequence. The phenomenon is described in the Var
turbidite system observed in the Ligurian Sea (northwestern Mediterranean) and consequently gives
a layer with a millimetre-to centimetre-thick inverse grading, without any structure (Migeon et al.,
2001). Another way to obtain a basal coarsening-upward unit, is by a two-layered turbidity flow.
Here, a basal laminar boundary layer moves below a turbulent top layer. In the basal layer, the
velocity of the flow is lower at the bottom than the top due to friction. This results in an inverse
grading within the flowing basal layer, since the size of the carried particles is proportional to the
15
velocity (Lowe, 1982), and is followed by coarser grains falling out of the turbulent top layer as the
energy of the flow decreases. The top of such turbidite deposits follow regular grading. These basal
coarsening-upward layers are always structureless and usually contain coarse particles (Mulder and
Alexander, 2001). A third type of basal coarsening-upward can be induced by a depletive waxing flow
(Kneller, 1995). Such hyperpycnal flow can be produced by a steadily growing discharge at a river
mouth, but only if the concentration of sediments is high enough (i.e. flood event). As long as the
flow velocity is below the erosion threshold, a coarsening-upward facies is deposited (Kneller and
Branney, 1995). Particles initially transported by a waxing flow are smaller (i.e. clay-silt fraction), but
increase in grain size as the flood event becomes stronger and coarser grains are brought into
suspension. These deposits often show sediment structures, such as current ripples.
In the study by Simonneau et al. (2013) in Lake Ledro, discussed in the previous section (3.1.1), grain
size is also used to make a distinction between earthquake-triggered turbidites and flood events.
Laser-diffraction grain size and bulk density analyses in these deposits clearly indicate that most of
their bases are successively inversely and normally graded, which is a typical signature of more
intense hyperpycnal flood deposits in a subaquatic basin (Mulder and Alexander, 2001; Mulder et al.,
2003; Mulder and Chapron, 2011; St-Onge et al., 2012). These successive coarsening upward and
fining upward sequences are correlated to the rising and the falling limb of a flood hydrograph and
will be discussed more into detail in the next section of this chapter (section 3.1.2). This lead to the
interpretation of the dark-coloured layers as deposits originating from strong hyperpycnal flood
events.
A study by Beck (2009) in Lake Anterne (northern Alps, France), a relatively small simple lacustrine
basin with on its south-eastern boundary a Gilbert-delta, gives more insight in the characteristics of
turbidites originating from floods driven primarily by spring/summer snow melting, and slump
turbidites resulting from slope failure of the steep delta foreset by gravity reworking processes
(overloading) or triggered by earthquakes. Since both show a rather similar organic matter signature
(i.e. organic matter from land plants), other parameters need to be involved to differentiate between
both. Gravity cores were taken along a profile proximal to distal from the delta foreset base,
containing thicker layers intercalated within the finely laminated sequences. These thicker layers
were interpreted as results of hyperpycnal flow deposits and were sampled and analysed for grain
size. Analysis showed that these beds clearly follow two different pathways on binary diagrams
relating skewness with sorting (SK/SO) and the coarse 99th percentile with the median (Passega’s
diagram; Passega, 1964). Beck (2009) concluded that slump turbidites typically have a coarser and
poorly sorted base, where the transition from the coarse base to the fine-grained top is rather sharp.
Furthermore, the granulometric contrasts appear reduced within the normal annual laminae. Flood
turbidites on the other hand are directly associated to the concentration of watershed runoff by-
passing the delta topset and foreset and rather stay in the grain size range of the regular annual
lamination, but with a slightly coarser mean grain size at the base. In contrary to slump turbidites,
strong flood related deposits have a well to moderately sorted base and typically consist of a
coarsening upward sequence (Beck, 2009). Though, different types of flood deposits can occur on a
smaller scale, depending on the load and related depositional process:
A less intense flood deposit may solely have a normal graded base, still pointing to a hyperpycnal
current (Mangili et al., 2005). It can enter the lake as an underflow due to the amount of suspended
16
matter and/or factors such as temperature (e.g. glacier runoff is relatively colder than its catchment
basin). While the turbidity current is spreading within the lake basin, the density difference will
reduce leading to a decreasing transport capacity and consequently finer grain sizes on distal
locations. This type of graded detrital deposit has a characteristic proximal-distal pattern, being
thicker and coarser at the river mouth and thinning out along its course towards the central basin of
a lake (Siegenthaler and Sturm, 1989).
Silt‐clay layers may be deposited when fine silt and clay detrital material is transported into the lake
by low‐density currents. These currents will continue their course into the water column as over‐ or
interflows (Sturm and Matter, 1978; Mangili et al.,2005) and eventually, the fine‐grained material
sinks and deposits within a few days on the lake bottom (Siegenthaler and Sturm, 1989). Sometimes
these layers may show some kind of faint grading. Another interpretation for this layer type, is that it
might reflect the distal deposits of high‐density currents from which the coarser fraction has already
been deposited (Mangili et al., 2005).
In some cases, layers are encountered containing various detrital and reworked sediment
components (e.g. littoral calcite, diatom frustules, plant remains) that are well mixed within the
sediment matrix (Czymzik et al., 2010). These are commonly thought to originate from major slope
failures or debris flows. An alternative explanation for the formation of these matrix-supported
detrital layers could be a strong river runoff event, where underflows have eroded material of the
delta topset and littoral zone of the lake, instead of by-passing it (Czymzik et al., 2010).
3.2 DEPOSIT TYPES
Sampled sediments can be divided into two major groups of deposits. All turbidites sampled in this
study are seismically-induced event deposits (SEDs) and sporadically interrupt the regular
hemipelagic “background” sedimentation, which is not influenced by earthquakes or any other
sudden or extreme event. The hemipelagic sediments have been described as fine-grained
hemipelagic sediments composed of laminated diatomaceous muds. The SEDs have been further
subdivided into three types of lacustrine turbidites (LT) based on their structure, grain size and
composition (colour, magnetic susceptibility, XRF signature and microscopic composition).
Two of these types of lacustrine turbidites can be differentiated from each other by comparing their
composition, being either similar to the hemipelagic sediment (LT1 type) or different from it (LT2
type) (Moernaut et al., 2014; Van Daele et al., 2015). They typically have a Ta and/or Te Bouma
division (Bouma, 1962). The LT1 type is produced by failure of lateral slopes of up to 20° (Adams et
al., 2001; Håkanson and Jansson, 2002; Strasser et al., 2011) and thus largely exists of reworked
hemipelagic sediments. Usually they are well-sorted and appear as a homogenous deposition with a
very thin, slightly more coarse base of fine sand fraction (< 2 mm thick; Ta-d) and a thin fine-grained
top of fine to medium silt (< 5 mm thick; Te), as determined by Van Daele et al. (2015). The LT2 type
usually contains coarser grains and is mostly poorly sorted in comparison to the LT1 type. Typically a
more terrestrial, organic richer imprint can be found. This more heterogeneous composition and
grain size distribution results in a homogenous to well-graded deposition with a Ta-b, Tc and/or Td
division, and a Te division (Van Daele et al., 2015). Source areas related to these types of lacustrine
turbidites could possibly be a river delta or relatively shallow near-shore areas, onshore landslides
17
that surged directly into the lake or that reached the lake in a more indirect way by means of debris
flows, mud flows or even floods.
The third type of turbidite has one or more Ta-d divisions and a thick (> 10 cm) Te division. These are
obviously thicker than the turbidite types described in the previous paragraph and are classified as a
megaturbidite (Van Daele et al., 2015). Their base exists of coarse grains (Ta-d) with above a thick
package of homogenous mud and on top a fine-grained clay to fine silt layer (Te). The source area of a
mass-wasting can occur onshore as well as offshore and is usually large enough to cause a lake
tsunami and potentially trigger a related seiche. Grain size fluctuations at the base of the
homogenous mud and the ponding geometry of the deposit have been attributed to the fluctuating
bottom currents associated with a lake seiche (Chapron et al., 1999; Schnellmann et al., 2006;
Bertrand et al., 2008a; Beck, 2009; Mulder et al., 2009).
3.3 REPORTS AND TURBIDITE DESCRIPTIONS
3.3.1 LAKE VILLARRICA: VI4, VI8, VI18
1960
According to the reports following the 1960 Valdivia earthquake, water rose north of Pucón (i.e.
eastern extremity of the lake; Fig. 4) while simultaneously dropping south of it. About fifteen minutes
after the observation, the lake level returned to its normal steady state. Water was also reported to
be “boiling” north of Pucón. Furthermore, numerous sightings of subsidence of beaches and deltas
around the lake were reported, but no major landslides were triggered in the catchment area of the
lake (Weischet, 1963; Sievers, 2000). In the cores taken in the southwestern sub-basin (VI4, VI8), LT1
type turbidites are present (Van Daele et al., 2015). In core VI18, taken to the west of the ridge in the
southeastern part of the lake, the deposit attributed to the 1960 earthquake was not cored.
2010
Reports state that a small tsunami occurred on the lake after the earthquake. In its eastern
extremity, near Pucón, a 2-3 m water level drop was witnessed instantly after the earthquake,
followed by a rise of 1-1.5 m above its regular steady state with an incoming wave. Shortly after this
oscillation, the water level returned to normal. Near-shore buoys of harbours in the area around
Pucón were pulled below the water line due to subsidence. Subsidence was also observed south of
the Trancura River inlet, where the beach disappeared completely. In the lake’s western extremity
(i.e. harbour of Villarrica), a water level rise of around 80 cm was reported immediately after the
earthquake, with subsequently a drop before returning to its normal steady state. During the
earthquake, sand blows were also noted on the beach of Villarrica town, suggesting liquefaction of
the (partially) saturated soil. All reports combined point in the direction of a small tsunami
propagating from east to west. Though, the event was not strong enough to create a lake seiche. No
landslides or other alterations were observed in the catchment area of the lake (Van Daele et al.,
2015). The cores taken in the southwestern sub-basin (VI4, VI8) contained some small (~ 1.5 cm) LT1
deposits (Moernaut et al., 2014). In the southeastern part of the lake (VI18) an LT1 is covered by an
LT2 , suggesting two density flows from a different source have reached this location (Van Daele et
al., 2015).
18
Fig. 4. Slope-shaded SRTM map of Lake Villarrica and Lake
Calafquén and their surrounding area with onshore reports,
local seismic intensities, bathymetry, SEDs and coring
locations. Used cores in this thesis are marked orange.
Adapted from Van Daele et al. (2015)
19
3.3.2 LAKE CALAFQUÉN: CGC1, CB4, CB9, CALA05, CALA08
1960
In contrary to Lake Villarrica, the catchment area as well as the shores of the eastern sub-basin of
Lake Calafquén were subjected to a lot of landslides (Fig. 4). Reports state that impact of these
landslides on the water surface triggered a main wave, followed by some small secondary waves in
the upper eastern end of the lake (Weishet, 1963; Wright and Mella, 1963; Sievers, 2000). Core
CALA05, taken in the southwestern sub-basin, contains an LT1 type turbidite attributed to the 1960
earthquake. In the eastern (CB4) and western (CB9) sub-basins of the lake, mass-transport deposits
occur. These are overlain by respectively one and two LT2 type turbidites, as determined by Van
Daele et al. (2015). Another core was taken in the eastern sub-basin (CGC1), a few hundreds of
meters southeast of CB4’s location. The base of the core shows a part of the LT2 type turbidite also
found in CB4, but a part is missing due to insufficient coring depth. In core CALA08, the deposits
attributed to the 1960 earthquake were not cored.
2010
Around the lake local near-shore subsidence was observed. Reports state that east of the peninsula
near Lican Ray, some buoys got submerged as a consequence of subsidence. West of the peninsula
no reports were made of disappeared buoys or other events attributed to subsidence. Large standing
waves were witnessed during the earthquake in Coñaripe. Sequentially, the water level of the lake
rose about one meter above its regular steady state before returning to its previous level.
Furthermore, the shoreline moved more landward after the earthquake, suggesting subsidence (Van
Daele et al., 2015). For the core taken in the southwestern sub-basin (CALA05) an LT1 type turbidite
was found as a consequence of the 2010 earthquake (Moernaut et al., 2014). Cores (CALA09,
CALA10; not used in this study) taken in the eastern sub-basin contain a mass-transport deposit
covered by a rather heterogeneous LT2. More to the center of this basin, this same LT2 becomes
more homogenous, were CALA08 is located (Van Daele et al, 2015).
3.3.3 LAKE RIÑIHUE: RI5, RI7, RI8
1960
No tsunami-like effects were reported for Lake Riñihue, though major landslides occurred near the
lake, resulting in a blockage of the outflowing San Pedro river (Fig. 5). As a consequence of this
natural dam formation attributed to the 1960 earthquake, the water level of the lake rose 26.85 m
during 63 days. The rise resulted in a connection between the neighbouring Lake Panguipulli. A
sudden dam breach could have had disastrous implications and would have destroyed all towns
along the course of the river, including the city of Valdivia. To avoid destruction of these cities, an
enormous manpower was put to service to control the outflow of the lake, called the Riñihuazo.
Despite the effort, the towns of Los Lagos, Antilhue, Pishuinco and the riverside areas of Valdivia
partially flooded (Davis and Karzulovíc, 1963; Weishet, 1963; Wright and Mella, 1963; Sievers, 2000).
The cores used in this study (RI5, RI7, RI8) were taken in the western sub-basin of the lake and all
showed an LT1 type turbidite (Moernaut et al., 2014). For core RI7, which was taken in the
northwestern part of this sub-basin, southeast of a small delta on the northern shore, an LT2 was
found below the LT1. The LT2 type turbidite exists of a 3.5 cm thick graded turbidite with a coarse
20
Fig. 5. Slope-shaded SRTM map of Lake Riñihue and Lake Rupanco and their surrounding area with onshore reports, local seismic intensities, bathymetry, SEDs and
coring locations. Used cores in this thesis are marked orange. Adapted from Van Daele et al. (2015)
21
sandy base. Only the top (~ 1 cm) could be classified as a LT1. More distal to this location (RI5), the
LT2 becomes thinner (~ 2.5 cm), while the LT1 becomes thicker (~ 5.5 cm; Moernaut et al., 2014).
2010
No reports were made of any unordinary events in or around the area of Lake Riñihue, which could
be attributable to the lack of witnesses present in the surrounding of the lake. Few people still live
near the coastline since the 1960 event. The only core in this study where deposits attributed to the
2010 earthquake were found, is core RI7. This core is located southeast of a small delta on the
northern shore of the northwestern sub-basin, where a 3 cm thick graded LT2 type turbidite was
found.
3.3.4 LAKE RUPANCO: RUP02BIS, RUP03TRIS, RUP04
1960
Numerous landslides were triggered by the 1960 earthquake. Some of which dumped directly into
the lake, others converged on land into mudflows and subsequently surged into the lake after the
earthquake, as is the case at two locations in its eastern extremity (Fig. 5). An LT2 that covers a
poorly developed fine-silt cap was encountered by Van Daele et al. (2013) at the top of the
megaturbidite. This indicates that the arrival of the LT2-forming turbidity flow (mudflow) was
noticeably delayed from the formation of the megaturbidite, but also that the LT2 was deposited not
too long after the formation of the megaturbidite. As a consequence of these landslides surging
directly into the lake, a large lake tsunami occurred strong enough to oscillate back and forth,
creating a seiche event. Subsidence effects were also noted as many narrow beaches around the lake
disappeared (Weishet, 1963; Wright and Mella, 1963). Cores were taken in the eastern sub-basin
(RUP02BIS), in the western sub-basin (RUP03TRIS), and in the southern sub-basin (RUP04) of the
lake. RUP02BIS contains a > 58 cm thick megaturbidite, covered by two relatively small (4 and 4.5 cm)
LT2 type turbidites. The megaturbidite was also encountered in other cores taken in the central
basin. In the western sub-basin, the megaturbidite is not present anymore and an LT1 is found with a
thickness of 7.5 cm. Core RUP04 holds a 13 cm thick LT2 turbidite.
2010
Since the Rupanco cores available for this study were collected during an expedition in 2009, there is
no data available on the SEDs triggered by the 2010 megathrust earthquake.
22
4. MATERIAL AND METHODS
4.1 SEDIMENT CORES AND SAMPLING
The gravity cores used in this study were acquired during two field expeditions in the years 2009 and
2011 (Table 2). Subsequently, they were shipped to Belgium, opened, described and photographed in
high detail, and further analysed (Van Daele, 2013; Moernaut et al., 2014; Van Daele et al., 2014; Van
Daele et al., 2015). Both earthquakes studied here are relatively recent events, thus the sedimentary
deposits resulting from these should show little to no burial. Deposits due to the 2010 Maule
earthquake are assumed to occur at the very top of the cores taken in early 2011. Deposits from to
the 1960 Valdivia earthquake were dated by intra-lake correlation with previously dated cores from
other studies, by varve counting or by inter-lake correlation based on tephra marker horizons by Van
Daele et al. (2015).
For this thesis study, turbidites attributed to the 1960 and 2010 megathrust earthquakes were
sampled continuously on the working half of fourteen cores from four different lakes of the Chilean
Lake District. Hemipelagic sediments were also sampled twice for each sampled turbidite, in order to
have a better understanding of the regular aseismic sedimentation. For turbidites with a thickness of
≤ 8 cm, a sample interval of 0.5 cm was used. For turbidites with a length exceeding 8 cm (e.g. CB9), a
sample interval of 1 cm was used. An exception is core RUP02BIS, which was sampled every 5 cm due
to its length with a sample thickness of 1 cm. The samples of hemipelagic sediment have a thickness
of 1 cm. In some cases, fungus was present on the foil-covered top of the core. This was first
removed with a glass slide or spatula before sampling took place.
Table 2. General information for all cores used in this thesis and thickness of the seismically-induced event
deposits that were attributed to the 1960 (red) or 2010 (blue) earthquake. Lake turbidite type 1: LT1; Lake
turbidite type 2: LT2; Megaturbidite: MT. Adapted from Supplement Van Daele et al. (2015)
Lake Core name Sampling
year
Lat.
(°N)
Long.
(°E)
Depth
(m)
Length
(cm)
Thickness of deposits (cm)
1960 2010 LT1 LT2 MT LT1 LT2
Villarrica VI4 2011 -39.28 -72.19 85 81 2 1
VI8 2011 -39.28 -72.16 113 95 5 1
VI18 2011 -39.28 -72.08 154 21 3 2.5
Calafquén CGC1 2009 -39.56 -72.06 178 25 4
CB4 2009 -39.55 -72.06 173 54 6
CB9 2009 -39.53 -72.14 170 45 9 + 7.5
CALA05 2011 -39.55 -72.18 88 119 4.5 1.5
CALA08 2011 -39.52 -72.15 194 20 12
Riñihue RI5 2011 -39.80 -72.39 121 62 5.5 2.5
RI7 2011 -39.79 -72.39 118 62 1 3.5 3
RI8 2011 -39.79 -72.40 118 73 5.5
Rupanco RUP02BIS 2009 -40.88 -72.24 262 81 4 + 4.5 > 58
RUP03TRIS 2009 -40.82 -72.51 268 44 10
RUP04 2009 -40.87 -72.49 97 59 13
23
4.2 SAMPLE PREPARATION
All 218 samples were dehydrated prior to analysis in the sedimentology lab (Dep. of Geology, Ghent
University). This was achieved by lyophilisation. By freezing the soil material and then reducing the
surrounding pressure, ice in the material is allowed to sublimate directly from the solid phase to the
gas phase. This dry sediment state was necessary for later application in C/N analysis. After freeze-
drying, samples were grinded and homogenised in an agate mortar.
4.3 LOSS ON IGNITION
Loss on ignition (LOI) is a commonly used method to estimate the organic and carbonate content of
sediments. It provides a fast and inexpensive tool with a precision and accuracy comparable to other,
more sophisticated geochemical methods (Dean, 1974). LOI is based on sequential heating of the
sediment samples at specific temperature ranges in a muffle furnace, resulting in a weight loss
closely related to the amount of organic matter and carbonates. Organic matter is oxidised at
temperatures around 550°C to CO2 and ash. In a second reaction at temperatures around 950°C,
transformation of carbonates result in CO2 and oxides. The latter heat treatment was not necessary
for this study, since the only interest was an estimation of the organic carbon content.
LOI preparation and measurements were all executed according to described protocol by Heiri et al.
(2001) in the sedimentology lab (Dep. of Geology, Ghent University). For all samples, approximately 1
g of freeze-dried material was placed in a preweighed porcelain crucible. These were then dried for
24 hours at 105 °C in the muffle furnace and placed in a desiccator for roughly 20-30 minutes to cool
down without reabsorbing any air moisture by hygroscopic clays in the sediment material. The
weight of the samples was then accurately measured before all samples were heated to 550 °C for 4
hours. Subsequently, the samples were again placed in a desiccator and re-weighed. The weight loss
associated to the oxidation of organic matter is closely related to the organic content in the sample
(e.g. Dean, 1974; Bengtsson and Enell, 1986). LOI550 is then calculated using the following equation:
𝐿𝑂𝐼550 = (𝐷𝑊105−𝐷𝑊550)
𝐷𝑊105× 100
𝐷𝑊105 = 𝑑𝑟𝑦 𝑠𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 𝑏𝑒𝑓𝑜𝑟𝑒 𝑐𝑜𝑚𝑏𝑢𝑠𝑡𝑖𝑜𝑛 (𝑔)
𝐷𝑊550 = 𝑑𝑟𝑦 𝑠𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 𝑎𝑓𝑡𝑒𝑟 ℎ𝑒𝑎𝑡𝑖𝑛𝑔 𝑡𝑜 550°𝐶 (𝑔)
The value for LOI550 gives then the percentage of dry weight loss at 550°C, which is an accurate
estimate of the weight percentage of organic matter in the sample. A list of the LOI results can be
found in the Appendix section.
4.4 CARBON AND NITROGEN ELEMENTAL AND ISOTOPIC ANALYSIS
4.7.1 SAMPLE PREPARATION
Prior to sample preparation for organic carbon and nitrogen isotope analysis, the total organic
carbon (TOC) was estimated in order to conduct a qualitative measurement. The ideal amount of
24
TOC for analysis lies between 0.8 and 1 mg. Previous studies in south-central Chile compared LOI550
and TOC values on similar soil samples and demonstrated the non-linear relationship between these
values (Bartels, 2012; Paesbrugge, 2013). However, TOC weight percentages are about half of the
LOI550 weight percentages, if the latter has an organic matter content above 4 %. LOI550 values below
4 %, on the other hand, are in general not directly related to TOC. Nearly all samples used in this
study exceeded the 4 % organic material. An empiric formula relating TOC and LOI550 was established
based on sample measurements of Bartels (2012) and Paesbrugge (2013), as stated below:
𝑇𝑂𝐶 (%) = 0.0097 × 𝐿𝑂𝐼550² + 0.1824 × 𝐿𝑂𝐼550 − 0.6822
𝑅2 = 0.9677
With the TOC content known for each sample, as calculated from LOI550, the ideal sample weight
could be determined in order to achieve a TOC content of 0.8 to 1 mg, where the average of both
was taken as target weight. Silver capsules (5x9 mm) were then filled with approximately the target
weight of freeze-died sample material. The final weight could differ up to 10 % of the target weight in
order to maintain a qualitative measurement. A list of the calculated TOC values, target weights and
final weights can be found in the Appendix section. Because of the limitations of the elemental
analyser (interfaced to a continuous flow isotope ratio mass spectrometer; EA-IRMS) used for this
analysis, the total sample weight is required to be < 75 mg, so complete combustion of the sample
material can be achieved, and had to contain less than 12 mg of carbon, as the IRMS detection limit
for carbon lies between 150 to 12,000 µg.
Once all capsules were balanced and arranged in 96-well trays, they were treated with 60 µl of
deionized (DI) water to wet the sediment material and with 60 µl of sulphurous acid (5-6 %) to
remove inorganic carbon in the form of carbonates, which may interfere with the measurement of
organic 13C in soil material (Verardo et al., 1990). This acid treatment is also the reason why silver
(Ag) capsules were used instead of the less expensive tin (Sn) capsules, as tin decomposes when
exposed to acid. Following the acidification, the samples were placed under an infrared heating lamp
overnight to improve complete reaction, so inorganic carbon, if present, was released as CO2.
Capsules were then folded using tweezers to tiny balls, organized in new clean trays, sealed and sent
for analysis to the UC Davis Stable Isotope Facility (SIF; U.S., California).
4.7.2 ANALYSIS AT UC DAVIS STABLE ISOTOPE FACILITY
The amount (µg) of carbon and nitrogen is determined by the EA-IRMS. By dividing these weights by
the total measured sample weights, we can determine the TOC and TN (total nitrogen) values, and
consequently the C/N ratio for each sample. Subsequently delta values of 13C and 15N were measured
by continuous flow isotope ratio mass spectrometry (CF-IRMS; 20-20 SERCON mass spectrometer)
after sample combustion to CO2 and N2 at 1000 °C in a reactor packed with copper oxide and lead
chromate. Following combustion, oxides were removed in a reduction reactor (reduced copper at
650°C). The helium carrier then flows through a water trap (magnesium perchlorate). CO2 and N2
were separated using a SUPELCO Carbosieve G column adsorption trap before entering the IRMS.
Before and after the sample peaks and preliminary δ15N (Air) and δ13C (V-PDB) values were
calculated, isotope ratios of the samples were compared to the ratios of pure cylinder gases injected
directly into the IRMS (Bertrand et al., 2010). The preliminary isotope values are then adjusted by
25
correcting the values for the entire sample series based on the known values of the included
laboratory standards. These laboratory standards have been previously calibrated against NIST
Standard Reference Materials (IAEA-N1, IAEA-N2, IAEA-N3, USGS-40, and USGS-41). The long term
standard deviation is 0.2 ‰ for δ13C and 0.3 ‰ for δ15N (Stable Isotope Facility UCDavis, 2016).
4.8 GRAIN SIZE ANALYSIS
4.8.1 SAMPLE PREPARATION
The analyses were performed on the siliciclastic fraction at exactly the same sample intervals as for
LOI and C/N with a Malvern Mastersizer 3000 laser-diffraction particle-size analyser (Malvern
Instruments Limited, Malvern, UK). To isolate the terrigenous fraction, sample material was
suspended in 10 ml DI water and boiled with excess H2O2 (35 %) until the reaction stopped in order
to remove organic matter. Subsequently, 1 ml of HCl (10 %) was added to the solution and boiled for
one minute to remove any carbonates present. One hundred ml glass beakers were then filled with
DI water, put aside for approximately 7 hours, giving time for all suspended particles to deposit, and
decanted. This cycle was then repeated in order to ensure that the pH of the final solution was close
to neutral. To remove biogenic silica, the mixture was boiled with 1 ml NaOH (8 %) for ten minutes
and the same procedure was followed to neutralize the pH of the final solution. As a final step before
measuring, 1 ml sodium hexametaphosphate (2 %) was added to the mixture and boiled shortly to
assure the complete disaggregation of the particles.
4.8.2 ANALYSIS WITH MALVERN MASTERSIZER
The principle behind laser diffraction analysis is based on Mie and Fraunhofer diffraction theory,
which suggests that the intensity of light scattered by a particle is directly proportional to the particle
size (Mudroch et al., 1997). The angle of the laser beam and the particle size are inversely
proportional related to each other, i.e. the laser beam angle decreases as the particle size increases
and vice versa (McCave et al., 1986). Analysis is accomplished by means of a red light source (He-Ne
laser; 632.8 nm) and a blue light source of shorter wavelength (LED; 470 nm) for the smallest
measureable grain sizes. Particle-size is then calculated by measuring the intensity of light scattered
as the laser beam passes through the suspension. The Malvern Mastersizer 3000 used in the
sedimentology lab (Dep. of Geology, Ghent University) can measure a particle size between 0.01-
3500 µm, with a manufacturer’s accuracy better than 0.6 % and precision better than 0.5 %. A laser
obscuration around 10 % was the objective to obtain good quality data for this type of fraction (i.e.
mostly clays). If laser obscuration would be significantly higher, measured data would be skewed due
to multiple scattering. If too low, the signal-to-noise ratio would be too low to have a representative
measurement.
Several test samples were first measured to determine the amount of sample needed for each
turbidite in order to achieve an obscuration of ~ 10 %. Results showed that 50 mg of freeze dried
sediment was sufficient for all cores, except for those of Lake Rupanco (RUP02BIS, RUP03TRIS and
RUP04) where 75 mg was needed. For three samples, not enough sample material was present as a
result of previous analyses (i.e. VI8 0.5-1.0, 35 mg; RUP03TRIS 10.5-11.0, 35 mg; RUP03TRIS 15.0-
15.5, 45 mg) and therefore might be a little skewed. The measurement settings used during these
26
analyses are described in Table 3. Mean grain sizes and sediment descriptions for each sample can be
found in the Appendix section.
Table 3. Settings used during grain size analysis on Malvern Mastersizer 3000.
Particle type Non-spherical particle mode Yes
Is Fraunhofer type No
Material properties Refractive index 1.550
Absorption index 0.010
Particle density 1.5 g/cm³
Different optical properties in blue light No
Dispersant properties Dispersant name Water
Refractive index 1.330
Level sensor threshold 100.000
Measurement duration Background (red) 12.00 s
Sample (red) 12.00 s
Perform blue light measurement Yes
Background (blue) 12.00 s
Sample (blue) 12.00 s
Assess light background stability No
Measurement sequence Aliquots 1
Automatic number of measurements No
Number of measurements 3
Delay between measurements 0.00 s
Pre-measurement delay 0.00 s
Measurement obscuration settings
Auto start measurement No
Obscuration low limit 10.00 %
Obscuration high limit 20.00 %
Enable obscuration filtering No
Accessory control settings Accessory name Hydro MV
Is accessory dry No
Stirrer speed 2500 rpm
Ultrasound percentage 10 %
Manual tank fill No
Degas after tank and cell fill No
Sonicate to stability No
Ultrasound mode Continuous (From measurement start)
Clean sequence settings Clean sequence type Normal
Sonicate during clean No
Analysis settings Analysis model General purpose
Single result mode No
Number of killed inner detectors 0
Blue light detectors killed No
Fine powder mode No
Analysis sensitivity Normal
Analysed as Mastersizer 3000E No
Result settings Result range is limited
Result Units Volume
Extend Result No
Result Emulation No
Averaging Averaging enabled No
27
5. RESULTS
In this section, results for LOI, TOC, C/N and grain size are elaborated in a section for each lake and
their respective cores. Since δ13C data does not provide any useful information regarding the
provenance of lacustrine turbidites (section 3.1.1; because delta values for all the aquatic organic
matter and land plants using C3 carbon fixation lie in the same range), no closer look will be taken to
this variable.
5.1 LAKE VILLARRICA
5.1.1 VI4
LOI
The 1960 SED encountered in core VI4 (T1) shows a relatively high LOI550 base value (Fig. 6), followed
by a minor increase where a maximum value is reached (10.22 %). Subsequently, values decrease
quickly towards the top (8.57 %), showing a similar result to those measured in hemipelagic
sediments (avg. 8.41 %). The turbidite resulting from the 2010 event (T2) could not be analysed with
the LOI method due to the lack of sufficient sample (approx. 1 g).
TOC & C/N
T1 shows a TOC of 3.94 % before increasing slightly to a maximum of 4.11 %. Subsequently, a gradual
decrease is observed towards the top (3.26 %). C/N atomic ratios display a similar pattern, where the
ratio observed at the base (11.17) increases to a maximum (11.82), before decreasing topwards.
Measurements for T2 give a TOC of 4.36 % at the base. TOC decreases slightly towards the top before
eventually increasing to the highest observed value for this core (4.54 %). Measured C/N ratios
present a similar pattern as TOC again. The base is marked by a ratio of 9.70 that decreases slightly
halfway the turbidite (8.80), before increasing to a final ratio of 9.32 at the top. C/N ratios for T1
clearly show elevated values, while those of T2 are very similar to the ones observed in hemipelagic
sediments (avg. 9.37).
Grain size
Grain size analysis of T1 demonstrates a normal grading with a basal mean grain size of 13.65 µm,
fining upward to a top mean grain size of 6.22 µm. The base exists of a trimodal, very poorly sorted
sandy mud (very fine sandy, very coarse silt), transitioning into a polymodal, poorly sorted mud (very
fine silt). T2 doesn’t really show any grading, but seems to have very similar mean grain sizes as those
measured for hemipelagic “background” sediments, which is on average around 5.40 µm.
Encountered sediments can be classified as a trimodal or polymodal, poorly sorted mud (very fine
silt), where the top is slightly coarse skewed.
5.1.2 VI8
LOI
In core VI8, the turbidite attributed to the 1960 earthquake (T1) shows a LOI550 value of 8.91 % at its
base, relatively similar to the hemipelagic sedimentation (avg. 9.25 %). This is followed by a sudden
28
drop (6.70 %) and rise (10.60 %), after which values remain more or less stable throughout the
turbidite upon decreasing again at the top (8.53 %). The similarity between the LOI550 value at the
base and the one from the hemipelagic sediment together with the subsequent drop might suggest
that the lower boundary of the turbidite was not sampled precisely enough and some hemipelagic
“background” got included, since the general trend for nearly all turbidite sequences in this study
shows the lowest LOI550 value at the base. The turbidite attributed to the 2010 event (T2) could not
be analysed due to the limited amount of available sample.
TOC & C/N
T1 commences with a TOC value of 3.19 %, nearly identical to the values observed in the hemipelagic
sediments (avg. 3.19 %), before dropping to its lowest value of 1.98 %. This represents the assumed
artefact as discussed for LOI550 (previous paragraph). The base is followed by a rapid increase to its
maximal TOC value (5.99 %), upon decreasing to an average value around 4.7 %, where it remains
relatively stable at for a few centimetres (12 to 14 cm). The top of the turbidite then decreases
further to a TOC value of 4.04 %, following the general trend. The C/N ratio displays a base value of
9.84, from where it increases to its maximum (14.93). This maximum is followed by a decrease
towards a C/N ratio of 12.15, shortly interrupted by a small peak (12.93) near the top. Compared to
the hemipelagic sediments (avg. 9.56), all C/N ratios taken in the 1960 turbidite deposit are elevated.
T2 on the other hand gives its highest TOC value at its base (4.22 %), before subsequently showing a
subtly decrease to 3.82 % TOC. Hemipelagic “background” sediments average out on a TOC value of
3.20 %. C/N ratios for this turbidite present a similar decreasing path, with the highest ratio at the
base (8.55) and lowest one at the top (8.21), comparable to the ratios observed in the hemipelagic
sediments (avg. 8.61).
Grain size
Analysis of T1 displays a mean grain size of 11.45 µm at the base, before promptly increasing to 23.03
µm and continuing in a normal graded sequence, fining upward to a mean grain size of 5.50 µm at
the top. This confirms the assumption made in the previous sections paragraphs, i.e. that the base of
the turbidite was not sampled precisely enough and some hemipelagic “background” got included.
The top of the event deposit has a similar mean grain size as the ones measured for the hemipelagic
samples (avg. 5.13 µm). The “real” lower boundary of the turbidite (15.0 to 15.5 cm) exists of a
polymodal, poorly sorted sandy mud (very fine sandy, very coarse silt), gradually fining up in the
event to a polymodal, poorly sorted mud (fine silt). A small peak (7.07 µm) can be seen near the top,
coinciding with the small peak also observed for C/N. T2 doesn’t really show any grading, but rather
mean grain sizes equivalent to the hemipelagic sediments, and can be classified as a mud existing of
fine to very fine silt.
5.1.3 VI18
LOI
The turbidite in core VI18 shows the lowest LOI550 value at the base (3.49 %), whereupon an increase
is observed (7.89 %) that remains relatively stable between 3 to 5 cm core depth. This is followed by
a small decrease in LOI550, with values ranging between 6.16 % to 6.72 % up till 0.5 cm of the top,
where a sudden increase is noted to 7.88 %. All LOI550 measurements from turbidite samples have a
lower value than those taken in the hemipelagic sediments (avg. 9.74 %).
29
TOC & C/N
The SED exhibits the lowest TOC value at its base (1.29 %) followed by a prompt increase towards its
maximum value of 3.25 %. This increase is then followed by a decrease in TOC that remains relatively
stable at around 2.6 %, besides some minor fluctuations, upon suddenly increasing at the top of the
sequence to 3.01 %. Average TOC for hemipelagic sediments (3.41 %) are higher in comparison to all
measured turbidite samples for this core. C/N results show some fluctuations around a ratio of 11 in
the lower half of the turbidite (2.5 to 5.5 cm), before suddenly increasing significantly to a maximum
ratio of 13.89. The point at which this abrupt increase is observed, coincides with a sharp colour
change in the core from lighter to darker sediments. The peak is then followed by a rapid decrease
towards the lowest measured ratio for this deposit (9.32). Compared to C/N ratios observed in the
hemipelagic sediments (avg. 9.89), the upper half of the SED obviously shows some elevated C/N
ratios, while in the lower half this contrast is less outspoken, though still clearly visible.
Grain size
Mean grain sizes measured for the SED in core VI18 show a coarse base (33.02 µm) fining upward to
a first minimum of 9.39 µm. This is followed by a rapid transition towards a next maximum in mean
grain size (15.92 µm), coincident with the abrupt colour change in the core, before fining upward
again to a second minimum of 7.20 µm, similar to the observed mean grain size for the hemipelagic
sediment (avg. 7.32 µm). This sequence clearly shows two normal graded sequences on top of each
other. The base of the event deposit is marked by a bimodal, poorly sorted sandy mud (very fine
sandy, very coarse silt) developing to a trimodal, poorly sorted mud (medium silt) at the first
minimum. A transition to a trimodal, poorly sorted mud (coarse silt) is then noted at the next
observed maximum, gradually changing to a polymodal, very poorly sorted sandy mud (fine sandy,
very fine silt) at the top.
30
Fig. 6. Results for the LOI550 measurements, the carbon and nitrogen isotopic analyses and the grain size
analyses for the cores VI4, VI8 and VI18. Artefact: VI4, mean grain size data point in the interval 19 to 20 cm
was lost.
5.2 LAKE CALAFQUÉN
5.2.1 CGC1
LOI
In core CGC1, a part of the SED could not be measured due to insufficient coring depth. The part that
was cored shows the top of the turbidite deposit also encountered in core CB4, since they are in
close proximity to one another (Fig. 4; Van Daele et al., 2015). The base of the core has a LOI550 value
of 2.43 % and decreases further to values between 1.24 % to 1.72 % (Fig. 7), which is very low
compared to the hemipelagic “background” sediments (avg. 8.48 %).
TOC & C/N
The event in core CGC1 has the lowest measured TOC values throughout this whole study. TOC
values show no trend and fluctuate in minor quantities between the values 0.29 and 0.45 %, which is
significantly lower than the hemipelagic “background” (avg. 2.77 %). C/N atomic ratios on the other
hand do display some trend. The base of the core marks an elevated C/N ratio of 14.04 compared to
the hemipelagic sediment (avg. 10.89), and is followed by a gradual decrease towards the top
(11.64). This gradual decreasing trend is shortly interrupted by a sudden trough (11.0) between 24.1
and 24.6 cm downcore.
31
Grain size
The SED contains very coarse material throughout its whole sequence, compared to the hemipelagic
sediments (avg. 9.62 µm). Analysis of the base shows a mean grain size of 64.57 µm, which gradually
decreases towards the top, where a mean grain size of 39.36 µm is measured. A small trough can be
observed in the interval 23.6 to 24.1 cm, coincident with the one observed for C/N. The base is
determined as a unimodal, poorly sorted muddy sand (very coarse silty, very fine sand) and shifts
towards the top to a unimodal, poorly sorted sandy mud (very fine sandy, very coarse silt).
5.2.2 CB4
LOI
Core CB4 shows the missing lower part of core CGC1. LOI550 measurements in CB4 demonstrate the
general trend, i.e. a low base value (5.41 %) with subsequent significant increase (9.75 %), shortly
followed by a decrease towards the top (4.76 %). The maximum LOI550 value measured in the
turbidite event (9.75 %) is similar to the value observed in the hemipelagic sediments (avg. 9.58 %).
TOC & C/N
The base of is marked by a low TOC value (1.89 %), followed by an increase towards its maximum
value (4.08 %). After reaching this maximum, a rapid decrease transitioning into a more gradual one
can be noted, eventually reaching its minimum value of 1.45 %. The hemipelagic samples are
characterised by an average TOC content of 3.08 %, thus exceeding nearly all of the measured values
throughout the turbidite, with exception of CB4 19.3-19.8 and CB4 19.8-20.3. C/N ratios present a
similar pattern as the one observed for TOC. The base of the turbidite shows a relatively lower ratio
of 12.30, which increases to a maximum of 17.03 in the same depth interval as for the observed TOC
peak (i.e. 19.3 to 19.8 cm downcore). This is followed by a decrease towards ratios around 12 with
some minor fluctuations, upon eventually decreasing to a minimum of 10.82, comparable to the C/N
ratios observed in hemipelagic sediment (avg. 10.21).
Grain size
A normal graded SED is shown with a basal mean grain size of 49.62 µm, fining upwards to a top
mean grain size of 4.71 µm, which is significantly lower than grain sizes measured for hemipelagic
sediments (avg. 7.66 µm). Some minor fluctuations are noted in between the top and base, but are
of no significance. Encountered sediments at the base can be classified as polymodal, very poorly
sorted muddy sand (very coarse silty, very fine sand) that transitions to unimodal, poorly sorted mud
(fine silt) towards the top.
5.2.3 CB9
LOI
The event deposit in core CB9 displays a comparable LOI550 path. A low base (3.19 %) is followed by a
gradual increase to values around 6.5 %, where it remains stable for about 4 cm (27.9 to 31.9 cm),
upon decreasing and reaching a new stable value around 5.1 % (19.9 to 26.9 cm). Only the very top
of the turbidite shows another decrease towards 3.85 %. All turbidite samples have a lower
measured LOI550 value in comparison to the hemipelagic sediments (avg. 7.13 %).
32
TOC & C/N
The TOC values from the turbidite samples show a stepwise increase to a maximum value of 2.29 %,
starting from the typical lower base (0.83 %). After reaching a maximum, TOC gradually decreases to
a next minimum (1.41 %), which coincides with a sharp colour change in the core, before increasing
again to a value around 1.6 %. Subsequent to this relatively steady interval (21.9 to 25.9 cm), a
gradual decrease to 0.93 % TOC is observed towards the top. Measurements on hemipelagic
sediments gave a mean TOC of 2.64 %, exceeding all turbidite samples. C/N ratios show an increase
to a first maximum of 11.07 (32.9 to 33.9 cm), before decreasing gradually towards the observed
colour change with measured ratios as low as 8.94. The first sample taken in this upper darker half of
the turbidite displays a sudden increase in C/N ratio, with maximum ratios reaching 10.92, upon
decreasing in a stepwise manner towards the top (8.18). Roughly two peaks are observed, separated
by a wide trough. The C/N ratios measured in these two peaks clearly indicate elevated values in
comparison to the observed hemipelagic “background” sediment (avg. 9.37).
Grain size
Analysis of the SED displays a coarse base with a mean grain size of 55.40 µm, gradually fining
upwards to a first minimum of 8.47 µm, similar to mean grain sizes observed for hemipelagic
sediments (avg. 8.58 µm). This minimum is followed by a rather sudden rise in grain size to a second
maximum of 18.32 µm, before gradually decreasing again to the lowest measured grain size for this
event deposit (6.14 µm). The rise in grain size occurs simultaneously with a change in colour from
lighter to darker sediments. Again, two normal graded sequences seem to be stacked above each
other, as was also the case for core VI18. The lower boundary is marked by a trimodal, poorly sorted
muddy sand (very coarse silty, very fine sand) that gradually changes into a polymodal, poorly sorted
mud (fine silt) near the first minimum. Subsequently, a deposition of polymodal, very poorly sorted
sandy mud (fine sandy, coarse silt) is determined at the base of the upper, darker part of the SED,
which slowly transitions into a bimodal, poorly sorted mud (very fine silt) near the top.
5.2.4 CALA05
LOI
Core CALA05 contains both SEDs triggered by the 1960 and 2010 earthquakes. The one attributed to
the 1960 event (T1) features a low LOI550 base value (6.43 %), succeeded by an increase to 8.66 %
with some minor variations throughout the turbidite, relatively similar to the hemipelagic
“background” (avg. 8.99 %). A dissimilarity with the general trend though, is a sudden increase in
LOI550 at the very top of the turbidite(9.34 %). The 2010 event deposit (T2) doesn’t really show any
kind of trend since only few samples could be measured due to limited amount of available
sediments. LOI550 measurements gave values of 11.64 % for the base and 10.98 % for the top, which
is slightly higher than those observed in the hemipelagic sediments (avg. 10.54 %).
TOC & C/N
TOC results for T1 present a low basal value of 1.93 %, abruptly increasing to a first maximum of 3.00
%. A subsequent gradual decrease is observed towards a TOC of 2.71 % before spiking to a value of
4.00 %. C/N displays a different pattern. Measured values roughly fluctuate between ratios of 8 and
9, where the spikes show a decreasing trend towards the top of the turbidite. For T2, TOC remains
relatively stable around 3.4 %. C/N results for this deposit are very low. The base is marked by a ratio
33
of 6.11, which somewhat increases toward the top (7.07). TOC for hemipelagic sediments is
determined at an average of 2.90, which does not differ so much for both measured turbidites,
besides the base and top value for T1. C/N ratios for these “background” sediments (avg. 7.89)
indicate elevated levels for the 1960 event in some degree, but hardly of significance.
Grain size
Measurements for T1 display a coarse base with a mean grain size of 31.81 µm that abruptly
decreases to 10.86 µm, from where a gradual decline in grain size can be noted towards a mean grain
size of 4.08 µm at the top. The base is marked by a polymodal, very poorly sorted sandy mud (very
fine sandy, very coarse silt), which develops towards a trimodal, very poorly sorted mud (very fine
silt) near the top. T1 thus shows a normal grading, in contrary to T2, which doesn’t show any clear
grading due to the lack of samples. The latter seems to have very similar mean grain sizes as the ones
observed for hemipelagic samples (avg. 5.11 µm) and an identical sediment texture, which is a poorly
to very poorly sorted mud (very fine silt).
5.2.5 CALA08
LOI
In core CALA08, the observed turbidite shows the lowest value at the base (5.63 %), followed by an
increase (6.72 %) with subsequent drop (5.92 %), before gradually increasing again to values around
7.3 % for the next couple of centimetres (4.5 to 8.5 cm). This steady depth range is then succeeded
by a slow decrease towards the top (6.32 %). Hemipelagic sediments are characterised by a relatively
high LOI550 value (avg. 10.05 %), exceeding all measured turbidite samples.
TOC & C/N
Elemental analysis presents the general trend for TOC. The lowest value is found at the base (1.71 %)
and is followed by an increase towards a maximum value of 2.58 %, before gradually decreasing in
the direction of the top (2.06 %). All turbidite samples have a lower TOC compared to the ones
observed in the hemipelagic sediments (avg. 3.01 %). C/N shows a gradual increase with ratios going
from 11.42 to 12.65, before decreasing near the top to 11.52. Background measurements in
hemipelagic sediments give an average C/N ratio of 8.05, pointing to elevated C/N levels in the
observed SED.
Grain size
Mean grain sizes demonstrate a gradual decrease from a coarse base (24.17 µm) towards a first
minimum (11.24 µm), from where a subtle increase can be noticed towards a mean grain size of
12.11 µm, before the final decline towards the top (8.83 µm) commences. The lower boundary can
be described as a unimodal, poorly sorted sandy mud (very fine sandy, very coarse silt) with a
transition towards the top to a trimodal, poorly sorted mud (medium silt). Hemipelagic “background”
sediments show an average mean grain size of 5.88 µm and can be classified as unimodal, poorly
sorted mud (fine silt).
34
35
Fig. 7. Results for the LOI550 measurements, the carbon and nitrogen isotopic analyses and the grain size
analyses for the cores CGC1, CB4, CB9, CALA05 and CALA08.
5.3 LAKE RIÑIHUE
5.3.1 RI5
LOI
LOI550 measurements for the event in core RI5 present a lower base value (10.47 %), followed by an
increase towards its maximum (12.42 %; Fig. 8). This maximum is followed by a gradual decrease
with some minor fluctuations near the top, showing a similar LOI550 signature as the measured
hemipelagic “background” sediments (9.15 %).
TOC & C/N
TOC levels for the show a gradual increase with respect to the base from 4.25 % to a maximum of
5.32 %. This is shortly followed by a sudden decrease towards 3.90 % TOC at the interval between
12.5 to 13.0 cm, coinciding with the observed colour change in the core. Subsequently TOC gradually
decreases further towards the lowest measured value for this event (3.36 %), before increasing again
at the top (3.77 %) to values similar to those measured in hemipelagic sediments (avg. 3.91 %). C/N
results show a nearly identical pattern as the one observed for TOC. A rise in C/N ratios is noted
relative to the base (12.02) towards a maximum of 14.60, before a sudden drop to 11.60 is observed
near the colour change. From here on, a gradual decrease commences to a minimum of 10.59, upon
spiking to a C/N ratio of 11.90 at the top of the turbidite. An average ratio of 10.78 was measured for
the hemipelagic sediments, clearly suggesting elevated levels for the lower (darker) part of the event
deposit and ratios somewhat similar to the “background” for the upper (lighter) part.
36
Grain size
The SED displays a mean grains-size of 15.21 µm at the base, which increases towards a first
maximum of 23.41 µm, before decreasing towards the observed colour change in the core to a mean
grain size of 18.79 µm. Around this colour change from darker to lighter sediments, an increase in
mean grain size is noted towards a second maximum of 23.75 µm. From here on, measurements
show a decrease towards the top, reaching a second minimum at 6.58 µm in the interval 8.5 to 9.0
cm, before subtly increasing again at the very top (8.37 µm). The observed minimum shows a similar
mean grain size as the ones observed for hemipelagic samples (avg. 6.71). The lower part of the SED
exists of a polymodal, very poorly sorted sandy mud (very fine sandy, very coarse silt), which
develops into a polymodal, poorly sorted mud (very fine silt) near the second minimum.
5.3.2 RI7
LOI
The 1960 SED in core RI7 (T1) displays a lower LOI550 value for the base (7.39 %) with subsequent
abrupt increase to its maximum value (13.65 %). A subsequent gradual decrease is observed towards
11.96 %, after which a small gradual increase can be noted towards the top (12.84 %). The 2010 SED
(T2) shows its lowest value also at the base (7.84 %) before increasing rapidly towards its highest
value of 16.99 %. This rapid increase is followed by a more gradual decrease towards the top (14.26
%). LOI550 measurements on hemipelagic sediments give a mean value of 10.13 %, lying in between
the observed minimum and maximum values of both turbidites.
TOC & C/N
T1 shows fluctuating TOC levels between 4.3 and 5.6 % with no distinct trend visible. The troughs
have a comparable TOC to those measured in hemipelagic sediments below the event (avg. 4.46 %).
C/N ratios on the other hand give an unmistakable pattern for intercalation of C3 plant derived
material. Hemipelagic sediments gave an average ratio of 10.81, while the base of the SED already
gives a ratio of 20.25, rising even further to the highest value observed in this study (26.13). This is
followed by a rather rapid decrease towards the top, reaching a minimum at 14.96, before slightly
increasing to 15.71 in the uppermost turbidite sample. TOC measurements for the T2 display the
lowest value at the base (3.64 %), followed by an increase to its highest value (8.25 %) and
subsequent decreasing towards the top (6.23 %). C/N shows a similar pattern, where a lower base
(11.32) is followed by an increase to its maximum (16.54), before gradually decreasing near the top
(13.84). Also this event clearly shows an elevation in C/N ratio compared to hemipelagic
sedimentation (10.81).
Grain size
Grain size measurements for the T1 show a coarse base, coarsening up further to a maximum mean
grain size of 64.40 µm. A subsequent decrease towards the top can be noted, reaching a minimum in
23.36 µm before suddenly increasing again at the very top to a mean grain size of 27.67 µm. The base
of the event exists of a unimodal, poorly sorted muddy sand (very coarse silty, very fine sand)
transitioning into a unimodal, poorly sorted sandy mud (very fine sandy, very coarse silt) near the
top. T2 also displays a normal graded sequence. The maximum mean grain size is reached
subsequent to the basal sample, giving a value of 50.35 µm. This maximum is followed by a gradual
decrease towards the top and reaches a minimum at a mean grain size of 19.76 µm. The sample
37
taken at the absolute top of the event deposit (0.0 to 0.5 cm) displays a sudden increase, with a
mean grain size of 25.26 µm. All measured grain sizes for both SEDs display significantly coarser
material throughout the whole deposit, compared to those observed in hemipelagic samples (avg.
9.23 µm). Sediments encountered in T2 can be described as a uni- to polymodal, very poorly sorted
sandy mud (very fine sandy, very coarse silt).
5.3.3 RI8
LOI
Measurements for the SED in core RI8 display a lower LOI550 value at the base (9.08 %), immediately
followed by a spiking increase (11.68 %) and subsequent decrease towards 8.73 %, before increasing
again to values around 9.4 % throughout the remaining part of the turbidite. LOI550 values of the
measured hemipelagic samples show a relatively wide range to be a representative “background”
measurement (6.04 % and 10.25 %).
TOC & C/N
TOC levels at the base of the SED (2.67 %) rapidly rise to a maximum (5.33 %), followed by a gradual
decrease towards 3.32 %. TOC then shortly rises to 3.44 %, before displaying a final decrease at the
top (3.15 %). C/N measurements on the other hand immediately show a maximum at the base of the
event (17.07) that gradually decreases to a minimum (10.24). The small hump noted in the TOC
pattern near the top is also observed for C/N. A short increase (10.60) is demonstrated subsequent
to the C/N minimum, before eventually decreasing again at the top (10.25). The interval between
13.2 to 14.9 cm evidently gives elevated levels for C/N compared to the hemipelagic “background”
(avg. 10.24), while those higher up the turbidite seem to give very similar measurements to those of
the hemipelagic samples.
Grain size
Analysis of the event deposit demonstrates a genuine normal graded succession. Mean grain sizes
gradually decrease from a coarse base (73.46 µm) towards a very fine-grained top (6.70 µm), similar
to the mean grain size measured for the hemipelagic samples (avg. 5.97 µm). The sediment texture
for the base can be classified as a trimodal, poorly sorted muddy sand (very coarse silty, very fine
sand). Towards the top of the event, sediments gradually transition into a trimodal, poorly sorted
mud (very fine silt).
38
Fig. 8. Results for the LOI550 measurements, the carbon and nitrogen isotopic analyses and the grain size
analyses for the cores RI5, RI7 and RI8. Artefact: RI7, δ13
C data point in the interval 16.5 to 17.5 cm was left out
due to poor chromatography.
5.4 LAKE RUPANCO
5.4.1 RUP02BIS
LOI
Core RUP02BIS contains a part of a megaturbidite (i.e. base was not cored; Van Daele et al., 2015).
LOI measurements show a very stable succession in the interval between 49.5 to 80.5 cm with LOI550
values increasing very subtly and gradually from 16.29 % towards 17.20 % (Fig. 9). Subsequently, a
steadily decrease is noted between 49.5 and 34.5 cm towards 13.41 %, followed by an increase,
stabilising at about 15.05 % (24.5 to 30.5 cm) upon decreasing again towards the top of the
megaturbidite to 10.50 %. The hemipelagic sediments show a stable, seemingly fixed LOI550 value at
about 8.68 %, clearly being a lower signature than any measurement taken in the event deposit.
TOC & C/N
Measured TOC displays a very consistent trend between 24.5 to 80.5 cm, only with some minor
variations around a mean TOC of 5.87 %. After this stable interval, a rather quick decrease is noted
somewhere between 19.5 and 24.5 cm towards 3.77 % TOC, which slightly decreases further near
the top to 3.69 %. These lower values at the top are relatively similar to the ones observed in
hemipelagic sediments (avg. 3.41 %). C/N results also give a very stable pattern with a mean value of
39
15.47 and minimum and maximum value of 14.55 and 16.04, respectively. Ratios for hemipelagic
sediments (avg. 12.24) point to elevated levels for the whole megaturbidite.
Grain size
The megaturbidite encountered in core RUP02BIS represents very steady mean grain sizes, ranging
around 8 to 10 µm for most part of the event deposit (25 to 81 cm), justifying the alternative term
“homogenite”. This steady interval is subsequently interrupted by a relatively small spike (12.19 µm),
before decreasing to the lowest mean grain size for this event (6.86 µm). In general, nearly all
measured mean grain sizes throughout this deposit are similar to the ones observed in hemipelagic
samples (avg. 9.89 µm). Sediments for the entire megaturbidite can be described as bimodal, poorly
sorted mud (medium silt). The data from the observed small spike and subsequent drop differs from
the megaturbidite in being trimodal and evolving into a finer sediment fraction (fine silt).
5.4.2 RUP03TRIS
LOI
The SED observed in core RUP03TRIS shows no distinct trend. LOI550 measurements throughout the
turbidite are characterized by values variating around 8.56 ± 0.82 %. Hemipelagic samples display a
wide variation in LOI550 “background” value, ranging from a similar signature as seen in the turbidite
deposit (8.16 %) to a value as low as 4.87 %.
TOC & C/N
The base of the event deposit is marked by 3.30 % TOC. This is followed by a decrease, remaining
relatively stable around 2.95 %, before increasing to a maximum observed value of 3.37 % for this
deposit. A subsequent rapid decrease (2.92 %) and increase (3.20 %) follows this maximum, before
eventually displaying a final decrease towards the top. Hemipelagic sediments show a wide range for
TOC (similar to the case for LOI550), being either similar to the values observed in the turbidite (2.87
%) or considerably lower (1.67 %). C/N measurements give a rather stable pattern with a mean ratio
of 9.79 (excluding peak values). Two peaks can be distinguished with a ratio of 11.22 and 10.44.
Compared to measurements in hemipelagic sediments (avg. 9.13), no significant difference can be
observed besides the two observed peaks.
Grain size
Mean grain sizes display a very subtle fining upwards succession. This fining upward trend is shortly
interrupted by a small peak between 10.5 and 11.0 cm, which may be due to the lack of sufficient
sediment during analysis (only 35 mg of sample was available for this interval, instead of the
calculated 75 mg). A mean grain size of 10.67 µm was determined for the base, which is followed by
a gradual decrease towards a mean grain size between 7 and 8 µm for the upper part of the event
deposit (5.5 to 10 cm). Sediments at the base exist of a trimodal, poorly sorted mud (medium silt)
transitioning to a more fine-grained bimodal, poorly sorted mud (fine silt). Observed grain sizes for
the SED seem very similar to the hemipelagic “background” sample taken in the interval between
17.0 to 18.0 cm. The hemipelagic sample taken between 18.0 to 19.0 cm on the other hand gives a
mean grain size significantly higher than any other measured value for this core (27.64 µm), which
may suggest that it is not representative for the regular steady state sedimentation.
40
5.4.3 RUP04
LOI
The turbidite deposit in core RUP04 demonstrates the general observed trend. The lowest LOI550
value is found at the base of the event deposit (8.96 %). This is followed by a significant increase,
almost twice as large as the value measured at the base (16.78 %), before dropping to 15.36 %.
Subsequently, the values increase again step by step, reaching a maximum at 18.21 %, before
decreasing towards the top (16.59 %). All turbidite samples, with exception of the base, exceed
measured hemipelagic values (avg. 12.93 %).
TOC & C/N
TOC for the SED in core RUP04 shows the lowest value at its base (3.36 %) from where an increase is
observed to a first peak value of 7.45 %. This is followed by a trough with a minimum of 5.72 % TOC,
before gradually increasing again to the highest observed value for this deposit (8.28 %). A
subsequent decrease is noted with a sudden rise at the very top (8.23 %). All measured TOC values
for the turbidite, with exception of the base, exceed the ones observed in hemipelagic samples (avg.
5.40 %). The general pattern for C/N ratios depicts a rise throughout the whole event deposit, with
some minor fluctuations in between. The base gives a ratio of 14.15, and increases towards the top
where a C/N ratio of 16.66 is determined. Two somewhat peaking values in this trend are observed,
marked by a ratio of 16.89 and 17.12. Measurements on hemipelagic sediments (avg. 12.02) indicate
elevated values for the whole turbidite.
Grain size
Grain size distribution displays a coarse base with a mean value of 30.41 µm, gradually decreasing
towards a first minimum of 21.07 µm. This minimum is followed by a sudden rise to a second
maximum mean grain size of 25.65 µm, before gradually fining upward again. A second minimum
(17.81 µm) is reached between 11.3 to 12.3 cm, which is followed by a stepwise increase to a third
maximum with a mean grain size of 19.55 µm, before commencing its final decrease towards the top
(15.59 µm). All measured grain sizes throughout the event clearly seem higher than the ones
observed for regular sedimentation in hemipelagic samples (10.86 µm). The coarse sediments at the
base can be classified as unimodal, poorly sorted sandy mud (very fine sandy, very coarse silt).
Towards the top, episodically more medium to coarse silt gets incorporated in the deposit, with
eventually a bimodal, poorly sorted mud (medium silt) at the very top.
41
42
Fig. 9. Results for the LOI550 measurements, the carbon and nitrogen isotopic analyses and the grain size
analyses for the cores RUP02BIS, RUP03TRIS and RUP04.
43
6. DISCUSSION
6.1 CORRELATION BETWEEN LOI5 5 0 AND TOC
As mentioned in the methods section (section 4.3), the weight loss associated to the oxidation of
organic matter during LOI analysis, is closely related to the organic content in the sample (e.g. Dean,
1974; Bengtsson and Enell, 1986). When comparing the LOI550 data with the TOC percentages
determined by the UC Davis SIF, all cases with exception of the events observed in core CALA05 show
a strong to very strong positive linear correlation (Table 4).
Table 4. Correlation between LOI550 and TOC values. Pearson correlation coefficient interpretation: 0.1 < |R| <
0.3 is a weak correlation; 0.3 < |R| < 0.5 is a moderate correlation; 0.5 < |R| < 1 is a strong correlation; |R| = 1
is a perfect correlation (Cohen, 1988).
Core Pearson correlation coefficient (R)
Number of samples (n)
VI4 0.97 8 VI8 0.86 13 VI18 0.93 13 CGC1 0.99 10 CB4 0.85 15 CB9 0.82 19 CALA05 0.50 15 CALA08 0.93 14 RI5 0.90 18 RI7 0.75 17 RI8 0.84 14 RUP02BIS 0.97 16 RUP03TRIS 0.74 19 RUP04 0.93 15
In general, TOC weight percentages are about half of the LOI550 weight percentages when sample
material contains more than 4% organic matter. In this study, estimations of TOC were calculated,
using the empiric formula obtained by Bartels (2012) and Paesbrugge (2013). Nearly all samples
exceeded this threshold, with the exception of the ones taken in core CGC1 (LOI550 values around
1.50 to 2.50 %) and a few other individual samples. When plotting the LOI550 percentages with the
TOC content, a similar relationship can be observed as demonstrated by the experimental formula
from Bartels (2012) and Paesbrugge (2013). Though, TOC values seem to be slightly underestimated.
The formula from Bartels (2013) and Paesbrugge (2012) was derived on the basis of 14 samples,
while for this study 206 measurements where used. To estimate the relationship between LOI550 and
TOC for this dataset, a linear regression was applied for the sediment samples. The linear trend is
then described by the formula:
𝑇𝑂𝐶 (%) = 0.4418 × 𝐿𝑂𝐼550 − 0.5524
𝑅² = 0.8939
The determination coefficient (R²) indicates that this model explains about 89.4 % of the variability of
calculated TOC values, which is statistically a very good fit. The slope (m = 0.4418) implies that about
44 % of the organic material consists of carbon. The x-intercept of approximately 1.25 % suggests
that other reactions beside the burning of organic matter take place at 550 °C. A reaction that may
44
contribute to the observed weight loss is continued dehydration of some clay minerals, since some
types of clay minerals still lose constituent water at temperatures higher than 105 °C (Murray and
White, 1955). Another potential reaction responsible for weight loss is the oxidation of metals in the
sample material. When fitting the dataset with a second degree polynomial function, a nearly
identical coefficient of determination is achieved (R² = 0.895). A power function on the other hand
shows a significant higher coefficient of determination (R² = 0.936), demonstrating the non-linear
relationship between TOC and LOI550 as described by Bartels (2012) and Paesbrugge (2013). The
observed values are thus best predicted by a power regression model:
𝑇𝑂𝐶 (%) = 0.2287 × 𝐿𝑂𝐼5501.218
𝑅² = 0.9355
Something worth noting is that the relationship between TOC and LOI550 displays a seemingly higher
variability for samples with a relatively high content of organic material (LOI550 > 10 %). A possible
reason explaining these fluctuations is the difference in TOC content between organic matter from
an algal origin and organic matter from woody plants. For example, diatom organic matter typically
has a mean overall TOC content of 25 %, while for wood TOC varies between 35 to 65 % (Hedges,
1975; Walsh, 1983). This dissimilarity results due to the presence of lignin in wood, which contains
about 50 % more carbon than cellulose (Benner et al., 1987). Therefore, in an oxic facies (e.g. studied
lakes) TOC content is often determined by variations in absolute phytoclast abundance (Tyson, 1995).
Nevertheless, LOI550 can be considered as a very useful tool to estimate TOC in samples on a local
scale and to optimise the amount of sediment needed for elemental and isotopic analyses of solid
materials.
45
Fig. 10. Relationship between TOC and LOI550 results for cores VI4, VI8, VI18, CGC1, CB4, CB9, CALA05, CALA08,
RI5, RI7, RI8, RUP02BIS, RUP03TRIS and RUP04. Linear, polynomial (2nd
degree) and power regression models
for observed dataset compared with the polynomial (2nd
degree) regression model of Bartels (2012) and
Paesbrugge (2013).
6.2 RELATION BETWEEN C/N ATOMIC RATIO AND GRAIN SIZE
Pearson correlation coefficients were determined between xx and yy for the events in the studied
cores, measuring the strength and direction of a potential linear relationship. Since it is mostly the
amount of nitrogen that changes in the different types of organic matter and not carbon, C/N values
were inverted (N/C) to achieve a more linear relationship (Perdue and Koprivnjak, 2007). No
consistent relationship between particle sizes and N/C ratios is present. A high variability in
coefficients is observed, with values mostly indicating weak negative linear trends (Table 5). Only for
the events in core VI4, CGC1, RI5, RI7 and RI8 there is a significant negative relationship between the
sediment mean grain size and the N/C ratios (p < 0.05).
Table 5. Correlation between grain size and N/C values. Pearson correlation coefficient interpretation: 0.1 <
|R| < 0.3 is a weak correlation; 0.3 < |R| < 0.5 is a moderate correlation; 0.5 < |R| < 1 is a strong correlation;
|R| = 1 is a perfect correlation (Cohen, 1988).
Core Pearson correlation coefficient (R)
p-value Number of samples (n)
VI4 -0.78 0.0074 10
VI8 -0.15 0.59 16
VI18 -0.32 0.28 13
CGC1 -0.70 0.035 9
CB4 0.23 0.35 14
CB9 -0.28 0.25 19
CALA05 -0.37 0.17 15
CALA08 -0.50 0.071 14
RI5 -0.88 1.2E-6 18
RI7 -0.83 3.4E-5 17
RI8 -0.95 4.1E-7 13
RUP02BIS 0.16 0.55 16
RUP03TRIS 0.39 0.10 19
RUP04 -0.50 0.059 15
N/C ratios and grain sizes are plotted in Figure 11. Only the SEDs originating from Lake Riñihue show
a consistent strong negative relationship between both quantities (R < -0.83). Here the coarsest
fraction coincides with the lowest measured N/C ratios (highest C/N ratios) and vice versa. This could
somewhat be expected, since in these coarse intervals macroscopic leaf and wood fragments were
found during sampling. The megaturbidite in core RUP02BIS shows a very weak positive linear
relationship according to the statistics (R = 0.16). In this case the correlation coefficient is misleading
due to minor variations around a relatively stable mean grain size and N/C ratio. The events in core
VI4 seemingly give a strong negative correlation, but this might be due to the limited amount of
samples for both events. The upper dark LT2 part of the event in core VI18 (R = -0.99) and the event
in core CGC1 also show a strong correlation, where the coarser fraction coincides with the lower N/C
ratios (or higher C/N ratios) and vice versa. However, in all other studied SEDs peaks and troughs
46
between both variables do not match and no consistent relation can be observed. Though, based on
the scatter plot relating grain size and N/C atomic ratio, it is safe to assume that a relationship in
general, if present, is negative and may show a relatively good linear correlation when land plant
derived material got included in the turbidity current (LT2 types).
Something worth noting is that for the same grain size, N/C ratios for the events in Lake Calafquén
are consistently higher than for those observed in Lake Riñihue (Fig. 11). An answer explaining this
observation might be found in the lake morphology and coring locations (Fig. 4 and 5). In Lake
Riñihue all coring locations are relatively near-shore since the lake has a lenticular, narrow shape. In
Lake Calafquén on the other hand, most core locations are rather far away from any onshore
sediment source.
The very low N/C values displayed by core RUP02BIS are also interesting. Only the fine-grained top of
this turbidite was cored and despite these very fine-grained sediments, N/C ratios are very low. This
clearly indicates an onshore source and suggests that N/C for this case is independent from the grain
size. This is probably because the complete megaturbidite is originating from a source onshore,
directly from slope failures.
Fig. 11. Relationship between mean grain size and N/C atomic ratio for cores VI4, VI8, VI18, CGC1, CB4, CB9,
CALA05, CALA08, RI5, RI7, RI8, RUP02BIS, RUP03TRIS and RUP04.
Another interesting observation is that C/N peaks sometimes seem “delayed” in comparison with the
coarsest fraction of the SEDs. A possible explanation for this is the difference in settling velocity
between coarse grains and organic material (e.g. plant fragments), where the latter may move
slower down the water column due to its shape, weight and buoyancy. Examples where such
47
“delayed” C/N peak can be observed, are the events in core VI4 (1960 SED), VI8 (1960 SED), VI18
(lower light part), CB4, CB9, CALA05 (1960 SED) and RUP04 (Fig. 6, 7 and 9).
6.3 INTERPRETATION C/N ATOMIC RATIO AND GRAIN SIZE
C/N atomic ratios and δ13C-values represent the whole mixture of organic components and can be
used to distinguish sources of organic matter in sediments. Three distinctive suites are relevant in a
lacustrine environment (Fig. 3), of which one (C4 plants) can be excluded due to its limited presence
in the nearby surrounding of the studied lakes, in contrary to the plants who follow a C3 carbon
fixation pathway. Comparison of these elemental and carbon isotopic values result in data points
between two endmembers, where organic matter originates from lacustrine algae on one side and
from organic matter from C3 land plants on the other side. In most cases it will be a mixture between
both. Therefore samples were also taken in hemipelagic “background” sediments, so an increased
influence from land plant derived organic matter compared to regular sedimentation could be
distinguished. δ13C-values range between -31.31‰ and -26.90‰, which is in agreement with the
expected algal and C3 plants signature. In the case a SED is composed of reworked hemipelagic
sediments, a similar signature will be observed as seen in the “background” samples for that event. If
a trend towards the C3 plants suite is displayed, a source of land based plants is involved. Depending
on the strength of this signal and reports from the 1960 and 2010 events, a more specific source area
can be appointed (e.g. onshore landslide, delta failure, mudflow, etc.).
The classification of turbidites applied in the next sections is based on the one used in Van Daele et
al. (2015), as discussed in section 3.2. Though, since in this study more information is obtained
regarding the sedimentary organic matter, a few adaptations are added. Depending on the
enrichment of organic matter originating from C3 land based vegetation, a distinction can be made
between LT1 type turbidites. On one hand, there are LT1 types that are solely the result of reworked
hemipelagic sediments, displaying a similar C/N ratio (algal imprint) as encountered for the
hemipelagic “background” samples. On the other hand, there are the LT1 types also resulting from
reworked hemipelagic sediments, but with a distinct trend to the field of C3 land plants (e.g. due to
proximity to the lake banks, near steep slopes). The former is abbreviated as LT1- (lack of terrestrial
imprint) and the latter as LT1+ (enriched in C3 derived OM). Data will be more elaborated in a section
for each lake.
6.3.1 LAKE VILLARRICA
Core VI4 was taken in the southwestern sub-basin of the lake at a depth of 85 m (Fig. 4). The 1960
SED (T1) present in the core shows a subtle increase in C/N towards the C3 plants endmember with a
maximum of 11.8, in comparison to the hemipelagic samples (~ 9.2; Fig. 12). This indicates that a
limited amount of land plant derived material got involved in the deposit. No major landslides were
reported during the 1960 earthquake, but numerous sightings of subsidence of beaches and deltas
around the lake were observed. Grain size analysis suggests that the event deposit exists of reworked
hemipelagic sediments (very fine silt) with some input of slightly coarser material at the base (very
fine sandy, very coarse silt). Since the core was taken relatively close to the shoreline (approx. 1 km),
sediments with a higher organic “background” from higher up the failing hemipelagic slope (closer to
land) could explain the moderately elevated C/N ratios (Heirman, 2011). Another possible
48
explanation can be found in the reports. Observations of near-shore subsidence. Some of this
subsided vegetation may have gotten included due to small-scale mass wasting, also explaining the
observed trend towards the field of terrestrial vegetation. Since there is a distinctive trend towards
land-based vegetation, this turbidite can be classified as a LT1+ type.
T2 at the top of core VI4 shows nearly identical C/N ratios as those observed in hemipelagic
“background” sediments (~ 9.5). Grain size analysis of the event resulted in the determination of a
very fine silt, again nearly identical to the hemipelagic “background” sediments. These results clearly
suggest that the turbidite attributed to the 2010 earthquake is solely the consequence of reworked
surficial hemipelagic slope sediments and can therefore be classified as a LT1- type turbidite. When
comparing these results to T1 in the same core (VI4), assuming they had the same source area, a
similar C/N signature is expected. Since this is not the case, the hypothesis of a near-shore mass
wasting/subsidence seems more plausible for the 1960 event.
Core VI8 was also taken in the southwestern sub-basin (Fig. 4), about 2.5 km east of core VI4 at a
depth of 113 m. T1 displays a clear trend towards the C3 field, with C/N values reaching a maximum
at 14.9, compared to values of ~ 9.5 for the hemipelagic samples. These elevated values clearly
suggest the incorporation of terrestrial vegetation in the turbidity flow. Grain size analysis of the
event shows a thin relatively coarse base (very fine sandy, very coarse silt), immediately followed by
sediments similar to the ones observed for the hemipelagic samples (fine silt). The sediment analysis
implies reworked hemipelagic slope sediments, though there is a clear imprint of land based C3
vegetation. A possible hypothesis for this organic imprint can be found in the reports, identical to the
1960 SED in VI4: surrounding vegetation may have been incorporated in the turbidity flow due to
subsidence/mass wasting, explaining the C3 land plant imprint in the sedimentary organic matter.
Based on the grain size analysis and the C3 imprint, this turbidite can be classified as an LT1+ type.
T2 in core VI8 is similar to the contemporaneous event in core VI4. C/N ratios indicate values very
much alike the ones observed in the hemipelagic samples (~ 8.5). Grain size analysis displays a
sediment texture of fine to very fine silt, which is identical to the one observed for the “background”
sediments. This data proposes sufficient evidence to conclude that the event deposit is the result of
reworked hemipelagic slope sediments, hence the classification as a LT1- turbidite.
Core VI18 is situated west of a ridge in the southeastern part of the lake and was taken around a
depth of 154 m (Fig. 4). Sediment description and grain size analysis clearly show two normally
graded sequences stacked on top of each other. This is also confirmed by the C/N measurements,
displaying a sharp boundary at the colour change of the sediment. In the lower (lighter) part of the
SED, C/N values are somewhat higher (max. 11.7) than those observed for hemipelagic samples (~
9.8). Grain size distribution of this part demonstrates the typical LT1 deposit type, where a thin
relatively coarse base is immediately followed by sediments very similar as those seen in the
hemipelagic “background” (medium to fine silt). The fact that the C/N ratios seem a little elevated is
not surprising, since several riverine systems have their outlet nearby the southern hemipelagic slope
proximal to the coring site, which is most likely the supplier of sediment for the observed event
deposit. From these slopes, slightly organic richer hemipelagic sediments were transported in a
turbidity current towards the basin floor. Considering the very limited difference in measured C/N
ratios and lack of a clear trend towards a terrestrial signature, this lower (lighter) part of the SED can
49
be classified as a LT1- type. The upper (darker) part of the SED clearly has an organic richer imprint,
with C/N values quickly rising to a maximum of 13.9. These values indicate an evident input of
organic matter originating from vegetation following the C3 carbon fixation pathway. Grain size
analysis shows an overall thicker sequence of coarser material (fine sandy, coarse silt) in comparison
to the lower part of the SED, confirming the conjecture of another source area than the hemipelagic
slopes. The fact that this overall coarser, more organic rich part of the SED is superimposed to the
part originating from the hemipelagic slopes, indicates that the distance to the source area should be
either considerably further or there was some delay between the start of both events, which is
unlikely (no reports of mudflows a posteriori). Reports were made of near-shore subsidence and
subsidence of beaches, which was also observed near one of the rivers inlets about 2.5 km south of
the coring site (Fig. 4). Liquefaction of the partially saturated soil was also noted around the lake
(sandblows). These reports together with the location of the coring site being relatively close to
several riverine outlets, points in the direction of a destabilisation of the river delta(s). This could
explain the obviously elevated C/N values and coarser sediments in comparison with the hemipelagic
samples. For these reasons, the turbidite can be classified as a LT2 type.
Fig. 12. δ
13C-values plotted against the C/N atomic ratios for all SEDs encountered in studied cores for Lake
Villarrica. Turbidites attributed to the 1960 earthquake are marked red, those attributed to the 2010
earthquake are marked blue.
50
6.3.2 LAKE CALAFQUÉN
Core CGC1 was cored in the eastern sub-basin at a depth around 178 m (Fig. 4). The base of the core
shows the top part of the 1960 SED, also found in core CB4. Figure 13 displays an increase in δ13C-
values compared to the hemipelagic “background” and a trend for C/N towards the C3 field. Though
one value (sample CGC1 22.1-22.6) differs significantly from the other samples. Since this sudden
trough in C/N ratios is not seen for the event in core CB4, no further relevance is given to this data
point. C/N values reach a maximum at 14.0, which is considerably higher compared to the
hemipelagic samples (~ 10.9). Grain size analysis indicates input of significantly coarser material (very
coarse silty, very fine sand) than found in the hemipelagic samples (medium silt), especially since
only the “fine grained” top of the SED is observed. Both datasets together suggest a source very close
to land or even onshore. Local reports made during the 1960 earthquake state that the shores of the
eastern sub-basin of Lake Calafquén were subjected to a lot of landslides. This fits the observations.
When looking at core CB4, which was taken a few hundreds of meters northwest of core CGC1’s
location at a similar depth, measured mean grain sizes seem to diminish. This implies that the
distance to the source area becomes larger. During sampling, a substantial amount of coarse wood
and leaf fragments were found at the base of the event deposit. C/N results also confirm the
pronounced C3 land vegetation signature, with a maximum ratio as high as 17.0, compared to a
“background” of ~ 10.2. This data also fits perfectly with the reports of landslides surging directly into
the lake. Since the SED in core CGC1 has a coarser top in comparison with the one in core CB4, it
most likely was closer to the source area. Taking the bathymetry and the surrounding relief into
account, the most probable source area for such landslides, are the vegetated steep hill slopes about
1.5 km south of core CGC1 (Fig. 4), which were also reported after the earthquake (Wright and Mella,
1963). Both 1960 SEDs from cores CGC1 and CB4 can be classified as an LT2 type turbidite.
Core CB9 was taken in the western sub-basin of the lake at a depth around 170 m (Fig. 4). C/N
results, grain size analysis and the sediment description clearly suggest that the observed SED exists
of two separate events stacked on top of each other: a lower, lighter part and an upper, darker part.
At the base of the lower part, fragments of woody material were found during sampling. A clear
imprint of land-based pants was expected, but only a subtle increase can be detected. A possible
cause for this is the poor homogenisation of the sample material. These coarser, robust wooden
chips got left out while filling the small fragile silver capsules to avoid piercing while folding.
Nevertheless, C/N ratios indicate elevated levels (max. 11.1) in comparison with hemipelagic samples
(~ 9.4). Grain size distribution displays a relatively thick, very-coarse silty to very-fine sandy base,
significantly coarser than encountered sediments for the hemipelagic samples. Combined data
suggests a terrestrial source for this event deposit. Since reports state a lot of landslides during the
1960 earthquake, this is the most likely explanation to the origin of the deposit, also clarifying the
presence of wood and leaf fragments. The lower (lighter) part can therefore be classified as a LT2
type. The upper part of the 1960 SED also displays slightly elevated C/N values (max. 10.9). Grain size
analysis concluded a thin somewhat coarser base (fine sandy, coarse silt) with a subsequent deposits
of sediments similar to the hemipelagic “background” samples (fine to very fine silt). The upper part
of the event deposit therefore seems to be the result of reworked sediments from the hemipelagic
slope, though with a subtle trend towards land-based plants. As a result, this turbidite may be
classified as a LT1+ type, rather than a LT2 type.
51
Core CALA05 was taken in the southwestern sub-basin at a depth of 88 m (Fig. 4). C/N measurements
in the 1960 SED show very low values, similar to the ones observed in hemipelagic samples. Grain
size analysis displays a typical LT1 deposit, where the base is marked by a thin deposit of coarser
sediments (very-fine sandy, very-coarse silt) and followed by sediments nearly identical to the ones
seen in hemipelagic samples (fine to very-fine silt). Consequently, this deposit is most likely the result
of reworked hemipelagic slope sediments and thus can be classified as a LT1- type. The same goes for
the 2010 SED at the top of core CALA05. C/N results and grain size analysis clearly suggest that the
event deposit is solely the result of reworked sediments from the hemipelagic slope.
Core CALA08 is located around the center of the lake and taken at a depth of 194 m (Fig. 4). C/N
atomic ratios are definitely elevated, with a measured maximum at 12.6, compared to ~ 8.8 for
hemipelagic samples. A clear trend towards terrestrial plants can be observed. When looking at the
grain size distribution, significantly coarser sediments (very-fine sandy, very-coarse silt to medium silt
at the top) are encountered than the ones observed in hemipelagic samples (fine silt). This fits the
description of a LT2 type turbidite. In a previous study by Van Daele et al. (2015), cores CALA09 and
CALA10 (not used in this study), taken about 1.6 and 3.0 km eastwards respectively, were described
containing a mass-transport deposit covered by a more heterogeneous LT2. In CALA08, this LT2
deposit becomes more homogenous. This suggests that the distance to the source area increases and
this location most likely can be found somewhere on the flanks of the eastern sub-basin.
52
Fig. 13. δ13
C-values plotted against the C/N atomic ratios for all SEDs encountered in studied cores for Lake
Calafquén. Turbidites attributed to the 1960 earthquake are marked red, those attributed to the 2010
earthquake are marked blue.
6.3.3 LAKE RIÑIHUE
Core RI5 was taken near the northwestern sub-basin of the lake at a depth of 121 m (Fig. 5). Grain
size analysis, C/N results and the sediment description clearly suggest that the SED is the result of
two density flows stacked on top of each other. Measured C/N ratios for the lower (darker) part
display a distinct trend towards the field of land plants (Fig. 14), while the upper (lighter) part shows
values in the range of the ones observed for hemipelagic samples. When looking at the lower part,
the grain size distribution demonstrates significantly coarser material. This information together with
the high C/N values (max. 14.6) implies a source area close to land or even onshore. The event can
therefore be classified as a LT2 type. A similar, thicker LT2 deposit is found in core RI7, about 450 m
north of core RI5. Both cores are in close proximity to a small river delta situated a bit northwest to
the core locations. Since the LT2 deposit becomes thicker more proximal to this delta and roughly
600 m to the west (core RI8; see next paragraphs) this LT2 is not (barely) found anymore, a river-
delta failure seems the most probable explanation for these deposits, confirming the hypothesis by
Moernaut et al. (2014). The upper (lighter) part of the 1960 SED encountered in core RI5 displays C/N
ratios and grain sizes very similar to the ones observed for hemipelagic samples. Since this deposit
seems solely the result of reworked sediments originating from the hemipelagic slope, this event can
be classified as a LT1- type.
Core RI7 is also located in the northwestern part of this sub-basin, about 450 metres north of core
RI5 at a depth of 118 m (Fig. 5). The SED attributed to the 1960 earthquake (T1) also exists of two
density flows stacked on top of each other, as determined by Moernaut et al. (2014). This is not so
clear, based on the acquired data during this study. However, this could be because of the relatively
“large” sample interval (0.5 mm) in comparison with the thickness of the upper density flow deposit
(~ 1 cm). The lower part of T1 displays distinct characteristics of an LT2 type: very high C/N values
(max. 26.1) and significantly coarser sediments compared to the regular hemipelagic sedimentation.
This was expected since during sampling coarse leaf and wood fragments were found in the interval
between 13.0 and 14.0 cm. The LT2 deposit is also found in core RI5, but seems to be thicker at this
location and mean grain sizes are higher. This points to a closer proximity to the source area. Very
high C/N values are observed for this lower deposit, with ratios directly in the field of terrestrial
plants. Since the core location is around 600 m downslope of a small river delta, the most probable
hypothesis is a delta failure with inclusion of lakeside vegetation. The upper deposit of T1 is similar to
the LT1 observed in core RI5, though a lot smaller (1 cm vs. 5.5 cm) and somewhat coarser. In
contrary to the LT1 in core RI5, C/N values still show a clear imprint of C3 vegetation. Therefore this
turbidite can be classified as a LT1+ type.
The 2010 SED in core RI7 again carries a typical LT2 signature. C/N ratios (max. 16.5) show a clear
trend towards terrestrial plant material and are significantly higher than the ones observed for
hemipelagic “background” samples (~ 9.6). Grain size analysis points to a source with considerably
coarser material than found on the hemipelagic slope. The SED appears to be very similar to the one
attributed to the 1960 earthquake and also seems to be originating from the small delta on the
53
northern shore of the northwestern sub-basin, again confirming the hypothesis by Moernaut et al.
(2014). These results clearly suggest that the C/N ratio is a valuable parameter that makes it easy to
distinguish between both source areas.
Core RI8 is also taken in the northwestern sub-basin at a depth of 118 m (Fig. 5). The base displays
C/N ratios with a clear signature of C3 plants (max. 17.1), which was expected since some leaf and
wood fragments were encountered during sampling (13.7 to 14.9 cm downcore). Furthermore, the
grain size distribution points to very coarse material (very coarse silty, very fine sand), at least for the
first centimetre of the SED. The remaining part of this deposit seems to show nearly identical C/N
values and grain sizes as observed for hemipelagic samples. Since the base expresses such a strong
influence from a land derived source, it might be a limb of the LT2 also observed in core RI5 and RI7,
originating from the small river delta roughly 1 km northwards of the core location. Despite the very
limited thickness of this deposit, it seems unlikely to be only the result of reworked hemipelagic
sediments. It can thus be seen as a SED existing of 2 density flows stacked on top of each other.
Therefore this base (13.7 to 14.9 cm downcore) can be classified as a LT2 type. Since the remaining
part is nearly identical to the hemipelagic samples, this can be classified as a LT1- type.
Fig. 14. δ
13C-values plotted against the C/N atomic ratios for all SEDs encountered in studied cores for Lake
Riñihue. Turbidites attributed to the 1960 earthquake are marked red, those attributed to the 2010 earthquake
are marked blue. The three yellow LT1 data points (Van Daele et al., 2015) with thick black borders can be
classified as part of a limb of the LT2 deposit based on this newly gathered data.
54
6.3.4 LAKE RUPANCO
Core RUP02BIS was taken in the eastern sub-basin of the lake, at a depth of 81 m (Fig. 5). C/N results
show very stable values around 15-16 (Fig. 15). Compared to the hemipelagic samples (~ 12.2), the
SED displays elevated C/N ratios, indicating sediment input from land. Grain size analysis determined
that the megaturbidite is built of similar relatively fine grain sizes than the ones observed in
“background” sedimentation, suggesting that a lot of sediments from the hemipelagic slope got
included. The base of the megaturbidite was not cored, so no coarse fractions or any vegetation
fragments are observed. Van Daele et al. (2013) noted that the top of the megaturbidite exists of two
LT2 deposits. Due to the large sample interval (5 cm), only one LT2 could be distinguished at the very
top (spike in mean grain size and C/N at 19.5 to 20.5 cm downcore). Based on the reports made
during the 1960 earthquake, the megaturbidite is the result of landslides surging directly into the
lake, together with mudflows originating from landslides that first converged on land. This new data
can confirm the hypothesis by Van Daele et al. (2015), where the thick megaturbidite most likely
finds its origin in the numerous landslides from the banks around the eastern sub-basin, while the
LT2 deposit at the top most likely is the result of a delayed turbidity current from a mudflow.
Core RUP03TRIS is located in the western sub-basin and was taken at a depth of 44 m. Grain size
distribution shows very low mean grain sizes throughout the whole sequence (medium to fine silt),
nearly identical to one of the hemipelagic samples. “Background” sample RUP03TRIS 18.0-19.0 BS is
not representative, displaying rather coarse material (very fine sandy, very coarse silt), and is
therefore not taken into account. C/N ratios demonstrate some minor fluctuations, with a maximum
value of 11.2, suggesting some minor input from land derived plant material following the C3
pathway. Based on this data, it is safe to conclude that the observed SED is the result of reworked
hemipelagic slope sediments, where the upslope source sediments contained a slightly higher C3
plant signature than the regular hemipelagic sedimentation on this location. Therefore this deposit
can be classified as a LT1+ type deposit.
Core RUP04 was drilled in the southern sub-basin of the lake, at a depth of 59 m. It hold a typical
example of an LT2 type deposit. Mean grain sizes display significantly coarser material (very fine
sandy, very coarse silt to coarse silt) than observed for the “background” sedimentation (medium
silt) and C/N ratios clearly show a significant elevation towards the C3 land plants field (max. 17.1).
Furthermore, leaf fragments were found throughout the sequence during sampling. Grain size
distribution seems to display a delayed input from a second density flow in the interval between 15.3
and 16.3 cm (a sudden rise in mean-grain sizes is noted; Fig. 9). Taking the reports into consideration,
the most likely source for this SED is material from landslides surging directly into the lake, together
with converged material transported by the nearby river (about 3.3 km southeast) spilling into the
lake.
55
Fig. 15. δ
13C-values plotted against the C/N atomic ratios for all SEDs encountered in studied cores for Lake
Rupanco. Turbidites attributed to the 1960 earthquake are marked red, those attributed to the 2010
earthquake are marked blue.
6.4 POTENTIAL OF C/N
C/N atomic ratios of bulk organic matter in lacustrine turbidites can be used as an easy tool in
determining whether the sediments rather have a (partially) terrestrial source or not, in comparison
with the regular hemipelagic sedimentation. This together with a good understanding of the lake’s
surrounding vegetation, watershed and bathymetry makes it possible to construct a highly probable
hypothesis of the provenance of the turbidite. Though, the usefulness of this method most likely
depends on the study site. The four lakes in this thesis display low stable C/N ratios around 8 to 10
for hemipelagic sediments (algal imprint due to high productivity), while sediments originating from
the lake’s surrounding slopes, near-shore areas and river delta give significantly elevated C/N ratios,
resulting in a clear distinction between a terrestrial or subaquatic sediment source. For areas where
“background” sedimentation shows higher and/or more variable C/N ratios (lower algal production),
distinction between source areas might be more complicated. In addition, the C/N ratio of every
organic matter source may vary greatly, even between plants within the same type of carbon fixation
group (e.g. C3: black locust vs. eucalyptus). In general, this method should work for different types of
vegetation covers, though the distinction between source areas might be more/less clear for certain
types of vegetation in the watershed.
56
7. CONCLUSIONS
The C/N atomic ratio in combination with sediment grain size analysis is a very useful parameter to
distinguish between several source areas in a lacustrine environment. Most clear results were given
by SEDs originating from hemipelagic slope failure, where there is a clear imprint of organic matter
from freshwater algae, and SEDs originating from landslides surging either directly/indirectly into the
lake or as a result of river delta foreset failure, with a strong signature of terrestrial material. Though,
a good understanding of the lake’s surrounding and bathymetry is imperative for a useful
interpretation. All analysed turbidites where seismically triggered, so no C/N related characteristics
of flood deposits or lahars could be studied, which might be interesting for future research.
One of the goals in this study was to determine whether there was any relationship between the C/N
ratio and the grain size distribution. The relationship between N/C and grain size in general shows a
negative tendency, though no consistent trend can be observed between the different SEDs. C/N is
not only driven by grain size (e.g. core RUP02BIS, very fine mean grain sizes and low N/C ratios vs.
core CALA05, for same grain sizes very high N/C ratios) and can therefore be used as a proxy to trace
the source area of the sedimentary organic matter. The ratios seem to be to an ideal tool to
disentangle contributions from aquatic and terrestrial organic matter sources in a lacustrine
enironment. Though, the method is most likely limited to study areas characterised by high algal
productivity (low stable C/N “background” values) in order to clearly distinguish terrestrial imprints.
Furthermore, based on this new dataset (n = 206), a more accurate regression model could be
constructed (R² = 93.6 %), relating LOI550 and TOC for the lakes Villarrica, Calafquén, Riñihue and
Rupanco (Chilean Lake District). It can also be noted that the relationship between both quantities
displays a seemingly higher variability for samples with a relatively high content of organic material
(LOI550 > 10 %).
57
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9. NEDERLANDSTALIGE SAMENVATTING
Een goed inzicht in het brongebied van lacustriene turbidieten kan de interpretatie van sediment
cores verbeteren en helpen in het reconstrueren van slope failure processen of in het begrijpen van
de events verantwoordelijk voor de sedimentdeformatie (bv. aardbevingen en floods). Vele studies
zijn reeds voorafgegaan, maar in deze thesis wordt een alternatieve parameter getest om de
oorsprong van de turbidieten te bepalen, nl. het koolstrof-stikstof (C/N) ratio. Dit ratio geeft de
atoomverhouding van organisch koolstof tot stikstof weer en wordt vaak gebruikt in
paleoklimatologisch onderzoek. Algemeen kan men stellen dat organisch materiaal van algen een
C/N ratio heeft van ongeveer 4 tot 8, terwijl dat van hogere landplanten (phylum Tracheophyta) een
C/N ratio heeft ≥ 20 (Premuzic et al, 1982;. Jasper en Gagosian, 1990; Meyers, 1994; Prahl et al.,
1994). Na de begraving van het organisch materiaal in meersedimenten, wordt de elementaire
verhouding van koolstof en stikstof voldoende bewaard om de vasculaire/non-vasculaire signalen te
herkennen (Meyers and Ishiwatari, 1993; Meyers, 1994). Daarom kunnen veranderingen in het C/N
ratio in lacustriene sedimenten geïnterpreteerd worden als zijnde verschuivingen in brondgebied,
waarbij het organisch materiaal eerder neigt naar een terrestrische signatuur of afkomstig is van
algen (Ishiwatari and Uzaki, 1987). Bovendien kan deze verhouding ook worden gebruikt om te
differentiëren tussen bepaalde groepen landplanten, afhankelijk van het soort koolstoffixatie ze
gebruiken (bv. C3 en C4 planten). Dit maakt deze methode een handig instrument voor het bepalen
van brongebieden van sedimentair organisch materiaal.
Het doel van deze thesis is om te onderzoeken in welke mate het C/N ratio kan gebruikt worden om
onderscheid te maken tussen brongebieden van lacustriene turbidieten, zoals hemipelagische slope
failures, rivierdelta failures, onshore landslides, flood gerelateerde events, modderstromen, etc. In
een volgende fase wordt er onderzocht of er een verband is met de korrelgrootteverdeling, daar het
C/N ratio vaak nauw samenhangt met de korrelgrootte van de klastische component (Howarth et al.,
2014). Uiteindelijk, als de vergaarde data en historische rapporten een consistente correlatie
vertonen, kan deze methode aangewend worden als een proxy voor long cores in toekomstig
lacustrien paleoseismisch/klimatologisch onderzoek. Om een antwoord hierop te vinden, werden 18
turbidieten van gekende oorsprong bemonsterd uit een reeks van cores genomen in verschillende
sedimentaire omgevingen.
Het studiegebied situeert zich in Zuid-Centraal Chili en is meer bepaald gericht op vier grote meren
die deel uitmaken van het Chilean Lake District (39°Z-41°Z): het Villarica, Calafquén, Riñihue en
Rupanco Meer. Alle meren zijn gelegen aan de voet van het Andesgebergte en vertonen een
gelijkaardige morfologie, limnologie en klimaat. De turbidieten zijn het gevolg van enerzijds de 1960
Valdivia aardbeving (Mw 9.5) en anderzijds de 2010 Maule aardbeving (Mw 8.8). Deze vinden hun
oorsprong in de aanhoudende oblieke subductie van de Nazcaplaat onder de Zuid-Amerikaanse Plaat
langsheen de Peru-Chilitrog.
De 14 cores gebruikt in deze studie zijn afkomstig van twee expedities in 2009 en 2011 (Van Daele,
2013; Moernaut et al., 2014; Van Daele et al., 2014; Van Daele et al., 2015). Per turbidiet werden er
twee hemipelagische “achtergrond” samples genomen met een dikte van 1 cm. De turbidieten
werden doorlopend gesampled met een sample interval van 0.5 cm indien < 8 cm en een sample
interval van 1 cm indien > 8 cm. Een uitzondering hierbij was de megaturbidiet in core RUP02BIS, die
66
omwille van zijn lengte om de 5 cm werd gesampled met een sample dikte van 1 cm. Vervolgens
werden alle 218 samples gevriesdroogd, gemalen en gehomogeniseerd alvorens van start te gaan
met de analyses.
Als eerste analyse werd LOI (Loss On Ignition) uitgevoerd om een schatting te maken van de inhoud
organisch koolstof voor ieder staal. Op basis hiervan kan een ruwe waarde berekend worden van het
TOC, zodat de hoeveelheid benodigd sediment voor een goede koolstof en stikstof elemental and
isotopic analysis kan geoptimaliseerd worden. De LOI methode is gebaseerd op het opeenvolgend
verhitten en wegen van de sediment samples volgens het protocol beschreven door Heiri et al.
(2001). Twee cycli werden doorlopen. Hierbij werden de stalen eerst verhit tot 105 °C gedurende 24
uur om het residuele vocht uit de kleien te verdrijven, waarna ze nogmaals verhit werden tot 550 °C
om het organisch materiaal te verbranden.
Vervolgens werden TOC waarden geschat volgens de empirische formule van Bartels (2012) en
Paesbrugge (2013) en werd er een ideale hoeveelheid sediment voor ieder sample bepaald.
Zilvercapsules werden gevuld met het desbetreffende gewicht voor ieder sample, aangezuurd met 60
µl zwavelzuur (5-6 %) om anorganisch koolstof te verwijderen, toegeplooid en geordend in 96-well
trays. Deze trays werden vervolgens opgestuurd naar het UC Davis Stable Isotope Facility (U.S.,
California). Hier werd de hoeveelheid (µg) koolstof en stikstof bepaald door de EA-IRMS (Elemental
Analyser verbonden met een continuous flow Isotope Ratio Mass Spectrometer). Door deze
hoeveelheden te delen door de gemeten gewichten van de samples, verkrijgt men de TOC en TN
waarden. Vervolgens werden ook de deltawaarden van de stabiele isotopen 13C en 15N gemeten. De
C/N ratios in combinatie met de δ13C waarden kunnen helpen om onderscheid te maken tussen
verschillende bronnen van organisch materiaal. Echter, aangezien de turbidieten afkomstig zijn van
brongebieden met zowel een soortgelijke samenstelling van gelamineerde hemipelagische
sedimenten als van onshore gebieden, kunnen we δ13C-waarden verwachten in het bereik van -25 tot
-30 ‰. Deze range komt overeen met de waarden van al het levend aquatisch organisch materiaal en
de C3 landplanten. Aangezien beiden in hetzelfde bereik liggen, zullen de δ13C-waarden geen verdere
informatie verschaffen in het onderscheiden van brongebieden. Vandaar het belang en de interesse
in C/N ratios. Deze zullen variëren tussen de eindleden van lacustrine algen (4-8) en C3 planten (≥ 20),
naargelang de vermenging met landmateriaal.
Gemiddelde korrelgroottes van ieder sample werden bepaald met behulp van een Malvern
Mastersizer 3000 laser diffraction particle-size analyser. De analyse werd uitgevoerd op de
siliciklastische fractie. Samples werden eerst behandeld met H2O2 (35 %), HCl (10 %) en NaOH (8 %)
om organisch materiaal, carbonaten en biogene silica respectievelijk te verwijderen. Om een
volledige disaggregatie van het samplemateriaal te verkrijgen, alvorens met de meting van start te
gaan, werd bij ieder sample 1 ml hexametafosfaat (2 %) toegevoegd.
Acheteraf werden LOI550 metingen en TOC data (n = 206) onderling vergeleken. Vrijwel alle events
vertoonden een zeer sterke positieve lineaire correlatie. Alle datapunten werden uitgezet in een
scatterplot, waar vervolgens een lineaire, polynomiale en machtsregressie werden op toegepast.
Hierbij leverde de laatste de hoogste determinatiecoëfficient op (R² = 0.936). Een gelijkaardige relatie
als die van Bartels (2012) en Paesbrugge (2013) werd waargenomen, hoewel deze de TOC
percentages van de gebruikte samples steeds licht onderschatten. Hetgeen werd opgemerkt in de
67
scatterplot, is dat de relatie tussen LOI550 en TOC bij hogere waarden voor organisch materiaal (LOI550
> 10 %) een steeds hogere spreiding vertonen. Een mogelijke verklaring voor deze fluctuaties is het
verschil in TOC-gehalte tussen organisch materiaal afkomstig van algen en organisch materiaal
afkomstig van houtige planten (bv. OM van diatomeeën heeft een gemiddeld TOC-gehalte van 25 %,
terwijl voor OM van hout TOC varieert van 35 tot 65 %; Hedges, 1975; Walsh, 1983). Vandaar dat in
een zuurstofrijk facies het TOC-gehalte vaak wordt bepaald door de variaties in absolute phytoclast
abundantie (Tyson, 1995). Niettemin kan LOI550 worden beschouwd als een zeer nuttig hulpmiddel in
het schatten van TOC op een lokale schaal en om de hoeveelheid sediment voor elemental and
isotopic analysis van vaste materialen te optimaliseren.
In een volgende stap werd gekeken naar de relatie tussen het C/N ratio en de gemiddelde
korrelgrootte. Aangezien het meestal de hoeveelheid stikstof is die verandert in de de verschillende
soorten organisch materiaal en niet de hoeveelheid koolstof, zijn de C/N waarden geïnverteerd (N/C)
om een meer lineaire relatie te verkrijgen (Perdue en Koprivnjak, 2007). Echter, hierbij werd geen
consistente relatie gevonden, maar eerder een hoge variabiliteit in correlatiecoëfficienten. Enkel de
events in cores VI4, CGC1 en deze genomen in het Riñihue Meer vertoonden een significante
negatieve relatie tussen het N/C ratio en de gemiddelde korrelgrootte (p < 0.05). Bij deze waar er een
significante relatie herkend werd, valt de grove fractie samen met de laagst gemeten N/C ratios
(hoogste C/N ratios) en vice versa. In alle andere onderzochte turbidieten komen de pieken en dalen
tussen beide variabelen niet overeen. Op basis van de scatterplot kan gesteld worden dat de relatie
(N/C en korrelgrootte), indien aanwezig, negatief is en een relatief goede lineaire correlatie kan
vertonen indien terrestrisch materiaal opgenomen werd in de turbidiet (LT2 types). De megaturbidiet
in core RUP02BIS toont aan dat deze relatie niet altijd opgaat. Hier werden lage N/C ratios
geobserveerd ondanks dat de fractie zeer fijnkorrelig is. Het feit dat deze fijnkorrelige top dergelijke
lage N/C waarden vertoont, suggereert dat de gehele megaturbidiet hoogstwaarschijnlijk zijn
oorsprong vindt op land. In dit voorbeeld is N/C volledig onafhankelijk van de korrelgrootte. Een
andere interessante observatie zijn de schijnbare “vertraagde” pieken voor C/N waarden in
vergelijking met de grofste korrelgrootte. Een mogelijke verklaring hiervoor kan te vinden zijn in het
verschil in bezinkingssnelheid tussen grovere korrels en organisch materiaal (bv. plantfragmenten),
waarbij het organisch materiaal trager in de waterkolom naar beneden beweegt vanwege zijn vorm,
gewicht en drijfvermogen.
In een slotfase werd alle vergaarde data geïnterpreteerd in combinatie met de historische verslagen
van het 1960 en 2010 event. Op basis hiervan konden weloverwogen hypotheses van de
brongebieden van de turbidieten opgesteld worden. De C/N ratios werden vergeleken met hun
“achtergrond” om te achterhalen of er een duidelijke bijdrage was van sedimentair organisch
materiaal vanop land (bv. via onshore lanslides, delta failure, modderstromen), of indien het louter
ging om herwerkte hemipelagische sedimenten door subaquatic slope failure. De indeling van de
turbidieten (LT1 en LT2) is gebaseerd op Van Daele et al. (2015). Het LT1 type bestaat hoofdzakelijk
uit herwerkte hemipelagische slope sedimenten en is het resultaat van lateral slope failure. Het LT2
type wijkt hiervan af door een grovere samenstelling te hebben dan de “achtergrond” en is meestal
gekenmerkt door een duidelijke terrestrische signatuur. Afhankelijk van de verrijking met organisch
materiaal kan er nog een onderscheid gemaakt worden binnen de LT1 types. Enerzijds zijn er LT1‘s
die uitsluitend het gevolg zijn van herwerkte hemipelagische sedimenten, waarbij een vergelijkbaar
C/N ratio (algen signatuur) wordt aangetroffen als voor de hemipelagische "achtergrond" samples.
68
Anderzijds zijn er de LT1 types die ook voortvloeien uit herwerkte hemipelagische sedimenten, maar
met een duidelijke invloed van terrestrisch organisch materiaal (bv. door subsidence, mass wasting,
vermenging met top slope hemipelagisch sedimenten met hoger C/N). Diegene zonder terrestrische
imprint worden afgekort als LT1-, terwijl diegene met een duidelijke trend worden afgekort als LT1+.
De meest duidelijke resultaten werden gegeven door turbidieten afkomstig van hemipelagische slope
failure, waar sprake is van een duidelijke signatuur van organisch materiaal afkomstig van algen, en
turbidieten die afkomstig zijn van landslides die zich ofwel direct/indirect in het meer storten of als
gevolg van een rivierdelta foreset failure, met een onmiskenbare signatuur van terrestrisch
materiaal. Echter, een goed begrip van de omgeving van het meer en bathymetrie is absoluut
noodzakelijk om tot een betrouwbare hypothese te komen.
Eén van de andere doelen van deze studie was om te bepalen of er een relatie is tussen het C/N ratio
en de korrelgrootteverdeling. De relatie tussen N/C en de korrelgrootte toont in het algemeen een
negatieve trend aan, maar is niet consistent. Hieruit kan opgemaakt worden dat C/N niet enkel
gedreven wordt door de korrelgrootte (bv. core RUP02BIS, zeer fijne gemiddelde korrelgrootte en
lage N/C-verhoudingen vs. core CALA05 voor dezelfde korrelgrootte hoge N/C verhouding) en kan
daarom gebruikt worden als een proxy om de herkomst van het sedimentair organisch materiaal op
te sporen. De ratios lijken een ideaal hulpmiddel te zijn om brongebieden van aquatisch en
terrestrisch organische materiaal te onderscheiden. Echter, de methode is hoogstwaarschijnlijk
beperkt tot gebieden die gekenmerkt worden door een hoge algenproductiviteit (lage stabiele C/N
"achtergrond") om een duidelijk onderscheid te kunnen maken in terrestrische signaturen.
69
10. APPENDIX
TABLE OF CONTENTS
1. Results LOI measurements…………………………………………………………………………………………………70
2. Results bulk organic geochemical analysis……………………………………………………………………………79
3. Results grain size analysis…………………………………………………………………………………………………….83
70
1. RESULTS LOI MEASUREMENTS
Sample label
Crucible Freeze dried sample weight (g) Dry (105ºC) sample weight (g) OM content
Notes Nr
Weight (g)
Crucible + sample (g) Sample
(g) Crucible + sample (g)
Sample (g)
Crucible + sample (g) Sample (g) Δ LOI550 (%)
RUP04 6.3-7.3 34 21.1804 22.1860 1.0056 22.1496 0.9692 21.9888 0.8084 0.1608 16.59
RUP04 7.3-8.3 28 20.4614 21.4611 0.9997 21.4398 0.9784 21.2737 0.8123 0.1661 16.98
RUP04 8.3-9.3 45 17.8142 18.8122 0.9980 18.7872 0.9730 18.6229 0.8087 0.1643 16.89
RUP04 9.3-10.3 6 18.2212 19.2186 0.9974 19.1967 0.9755 19.0268 0.8056 0.1699 17.42
RUP04 10.3-11.3 13 17.1097 18.1115 1.0018 18.0915 0.9818 17.9127 0.8030 0.1788 18.21 Leaf fragments throughout
RUP04 11.3-12.3 16 20.3335 21.3330 0.9995 21.3091 0.9756 21.1459 0.8124 0.1632 16.73
RUP04 12.3-13.3 2 17.7386 18.7334 0.9948 18.7095 0.9709 18.5449 0.8063 0.1646 16.95
RUP04 13.3-14.3 40 17.4614 18.4634 1.0020 18.4472 0.9858 18.2929 0.8315 0.1543 15.65
RUP04 14.3-15.3 46 18.6412 19.6417 1.0005 19.6234 0.9822 19.4725 0.8313 0.1509 15.36
RUP04 15.3-16.3 37 20.6015 21.6034 1.0019 21.5839 0.9824 21.4191 0.8176 0.1648 16.78
RUP04 16.3-17.3 15 21.1906 22.2003 1.0097 22.1710 0.9804 22.0140 0.8234 0.1570 16.01
RUP04 17.3-18.3 21 21.0365 22.0337 0.9972 22.0084 0.9719 21.8673 0.8308 0.1411 14.52
RUP04 18.3-19.3 36 17.8247 18.8267 1.0020 18.8009 0.9762 18.7134 0.8887 0.0875 8.96
RUP04 21.0-22.0 BS 17 18.4189 19.4134 0.9945 19.3743 0.9554 19.2435 0.8246 0.1308 13.69
RUP04 22.0-23.0 BS 7 17.8807 18.8845 1.0038 18.8551 0.9744 18.7366 0.8559 0.1185 12.16
CGC1 21.1-21.6 19 20.1579 21.1528 0.9949 21.1481 0.9902 21.1313 0.9734 0.0168 1.70
CGC1 21.6-22.1 11 19.7439 20.7472 1.0033 20.7439 1.0000 20.7315 0.9876 0.0124 1.24
CGC1 22.1-22.6 4 20.6923 21.6947 1.0024 21.6905 0.9982 21.6765 0.9842 0.0140 1.40
CGC1 22.6-23.1 10 17.0979 18.0932 0.9953 18.0919 0.9940 18.0748 0.9769 0.0171 1.72
CGC1 23.1-23.6 30 17.5169 18.5158 0.9989 18.5145 0.9976 18.4997 0.9828 0.0148 1.48
CGC1 23.6-24.1 22 20.7104 21.7116 1.0012 21.7088 0.9984 21.6918 0.9814 0.0170 1.70
CGC1 24.1-24.6 23 19.1810 20.1884 1.0074 20.1846 1.0036 20.1674 0.9864 0.0172 1.71
71
CGC1 24.6-25.0 3 17.7999 18.7939 0.9940 18.7922 0.9923 18.7680 0.9681 0.0242 2.44
CGC1 2.0-3.0 BS 31 21.3405 22.3484 1.0079 22.3394 0.9989 22.2624 0.9219 0.0770 7.71
CGC1 3.0-4.0 BS 14 20.1813 21.1823 1.0010 21.1672 0.9859 21.0761 0.8948 0.0911 9.24
CALA08 0.5-1.5 20 21.3192 22.3161 0.9969 22.2928 0.9736 22.2313 0.9121 0.0615 6.32
CALA08 1.5-2.5 24 21.4584 22.4561 0.9977 22.4392 0.9808 22.3743 0.9159 0.0649 6.62
CALA08 2.5-3.5 25 19.3763 20.3746 0.9983 20.3594 0.9831 20.2925 0.9162 0.0669 6.81
CALA08 3.5-4.5 39 20.1059 21.1074 1.0015 21.0957 0.9898 21.0293 0.9234 0.0664 6.71
CALA08 4.5-5.5 8 16.6930 17.6950 1.0020 17.6833 0.9903 17.6099 0.9169 0.0734 7.41
CALA08 5.5-6.5 1 17.9033 18.9038 1.0005 18.8895 0.9862 18.8186 0.9153 0.0709 7.19
CALA08 6.5-7.5 32 21.6009 22.6048 1.0039 22.5872 0.9863 22.5167 0.9158 0.0705 7.15
CALA08 7.5-8.5 43 18.4379 19.4350 0.9971 19.4235 0.9856 19.3500 0.9121 0.0735 7.46
CALA08 8.5-9.5 12 18.6029 19.6054 1.0025 19.5928 0.9899 19.5307 0.9278 0.0621 6.27
CALA08 9.5-10.5 44 16.9825 17.9893 1.0068 17.9801 0.9976 17.9210 0.9385 0.0591 5.92
CALA08 10.5-11.5 49 20.4072 21.4042 0.9970 21.3891 0.9819 21.3231 0.9159 0.0660 6.72
CALA08 11.5-12.0 26 19.6366 20.6365 0.9999 20.6240 0.9874 20.5684 0.9318 0.0556 5.63
CALA08 14.0-15.0 BS 72 21.0050 22.0033 0.9983 21.9749 0.9699 21.8799 0.8749 0.0950 9.79
CALA08 15.0-16.0 BS 27 20.4962 21.4965 1.0003 21.4751 0.9789 21.3742 0.8780 0.1009 10.31
RI8 8.7-9.2 5 20.4290 21.4271 0.9981 21.3909 0.9619 21.3026 0.8736 0.0883 9.18
RI8 9.2-9.7 18 18.2662 19.2645 0.9983 19.2283 0.9621 19.1369 0.8707 0.0914 9.50
RI8 9.7-10.2 41 21.1077 22.1080 1.0003 22.0654 0.9577 21.9764 0.8687 0.0890 9.29
RI8 10.2-10.7 60 17.5537 18.5575 1.0038 18.5205 0.9668 18.4279 0.8742 0.0926 9.58
RI8 10.7-11.2 9 20.8092 21.8082 0.9990 21.7689 0.9597 21.6795 0.8703 0.0894 9.32
RI8 11.2-11.7 38 18.6961 19.6570 0.9609 19.6220 0.9259 19.5325 0.8364 0.0895 9.67
RI8 11.7-12.2 35 19.8735 20.8714 0.9979 20.8353 0.9618 20.7513 0.8778 0.0840 8.73
RI8 12.2-12.7 29 21.6756 22.6745 0.9989 22.6332 0.9576 22.5462 0.8706 0.0870 9.09
RI8 12.7-13.2 33 21.0936 22.0929 0.9993 22.0564 0.9628 21.9667 0.8731 0.0897 9.32
RI8 13.2-13.7 57 18.0432 19.0451 1.0019 19.0183 0.9751 18.9250 0.8818 0.0933 9.57
72
RI8 13.7-14.2 68 20.8523 21.8556 1.0033 21.8189 0.9666 21.7027 0.8504 0.1162 12.02 Wood fragments
RI8 14.2-14.7 52 18.2702 19.2774 1.0072 19.2602 0.9900 19.1446 0.8744 0.1156 11.68 Wood fragments
RI8 14.7-14.9 61 20.9544 21.9539 0.9995 21.9417 0.9873 21.8521 0.8977 0.0896 9.08 Wood + leaf fragments
RI8 16.0-17.0 BS 56 20.6406 21.6455 1.0049 21.6268 0.9862 21.5257 0.8851 0.1011 10.25
RI8 22.0-23.0 BS 66 20.8435 21.8429 0.9994 21.8230 0.9795 21.7638 0.9203 0.0592 6.04
CALA05 0.0-0.5 71 17.9710 18.9716 1.0006 18.9374 0.9664 18.8313 0.8603 0.1061 10.98
CALA05 0.5-1.0 59 17.2001 18.1212 0.9211 18.0888 0.8887 17.9935 0.7934 0.0953 10.72
CALA05 1.0-1.5 47 17.7777 18.7720 0.9943 18.7346 0.9569 18.6232 0.8455 0.1114 11.64
CALA05 3.0-4.0 BS 70 21.5773 22.5799 1.0026 22.5450 0.9677 22.4447 0.8674 0.1003 10.36
CALA05 4.0-5.0 BS 48 16.7090 17.7012 0.9922 17.6541 0.9451 17.5528 0.8438 0.1013 10.72
CALA05 6.5-7.0 67 17.7582 18.7533 0.9951 18.7301 0.9719 18.6393 0.8811 0.0908 9.34
CALA05 7.0-7.5 62 20.7076 21.7068 0.9992 21.6755 0.9679 21.5961 0.8885 0.0794 8.20
CALA05 7.5-8.0 76 21.8173 22.8114 0.9941 22.7772 0.9599 22.6985 0.8812 0.0787 8.20
CALA05 8.0-8.5 58 17.6246 18.6216 0.9970 18.5892 0.9646 18.5070 0.8824 0.0822 8.52
CALA05 8.5-9.0 51 20.6903 21.6975 1.0072 21.6695 0.9792 21.5771 0.8868 0.0924 9.44
CALA05 9.0-9.5 54 18.5409 19.5466 1.0057 19.5176 0.9767 19.4345 0.8936 0.0831 8.51
CALA05 9.5-10.0 3 17.7994 18.7947 0.9953 18.7693 0.9699 18.6844 0.8850 0.0849 8.75
CALA05 10.0-10.5 75 21.1023 22.1014 0.9991 22.0683 0.9660 21.9846 0.8823 0.0837 8.66
CALA05 10.5-11.0 36 17.8245 18.8219 0.9974 18.8052 0.9807 18.7421 0.9176 0.0631 6.43
CALA05 13.0-14.0 BS 31 21.3399 22.3359 0.9960 22.2844 0.9445 22.2042 0.8643 0.0802 8.49
CALA05 14.0-15.0 BS 10 17.0977 18.0915 0.9938 18.0528 0.9551 17.9622 0.8645 0.0906 9.49
CB4 1.2-2.2 BS 30 17.5162 18.5153 0.9991 18.4831 0.9669 18.3871 0.8709 0.0960 9.93
CB4 2.2-3.2 BS 11 19.7435 20.7455 1.0020 20.7162 0.9727 20.6264 0.8829 0.0898 9.23
CB4 14.8-15.3 46 18.6410 19.6429 1.0019 19.6185 0.9775 19.5719 0.9309 0.0466 4.77
CB4 15.3-15.8 79 20.6985 21.6919 0.9934 21.6700 0.9715 21.6161 0.9176 0.0539 5.55
CB4 15.8-16.3 50 21.0735 22.0750 1.0015 22.0578 0.9843 21.9993 0.9258 0.0585 5.94
CB4 16.3-16.8 73 21.2599 22.2545 0.9946 22.2308 0.9709 22.1754 0.9155 0.0554 5.71
73
CB4 16.8-17.3 53 18.7942 19.7938 0.9996 19.7673 0.9731 19.7143 0.9201 0.0530 5.45
CB4 17.3-17.8 77 21.4111 22.4188 1.0077 22.3956 0.9845 22.3376 0.9265 0.0580 5.89
CB4 17.8-18.3 69 20.4485 21.4485 1.0000 21.4256 0.9771 21.3705 0.9220 0.0551 5.64
CB4 18.3-18.8 64 19.8095 20.8080 0.9985 20.7808 0.9713 20.7254 0.9159 0.0554 5.70
CB4 18.8-19.3 65 19.5925 20.5928 1.0003 20.5698 0.9773 20.5081 0.9156 0.0617 6.31 Wood chips
CB4 19.3-19.8 55 17.5662 18.5647 0.9985 18.5373 0.9711 18.4590 0.8928 0.0783 8.06 Leaf + wood fragments
CB4 19.8-20.3 78 18.0544 19.0503 0.9959 19.0280 0.9736 18.9331 0.8787 0.0949 9.75 Leaf + wood fragments
CB4 20.3-20.8 22 20.7102 21.7133 1.0031 21.6916 0.9814 21.6344 0.9242 0.0572 5.83 Wood chips
CB4 20.8-21.3 74 20.7689 21.7663 0.9974 21.7461 0.9772 21.6932 0.9243 0.0529 5.41 Wood chips
VI18 0.0-0.5 63 21.0376 22.0358 0.9982 21.9968 0.9592 21.9212 0.8836 0.0756 7.88
VI18 0.5-1.0 7 17.8810 18.8821 1.0011 18.8540 0.9730 18.7940 0.9130 0.0600 6.17
VI18 1.0-1.5 2 17.7390 18.7395 1.0005 18.7134 0.9744 18.6512 0.9122 0.0622 6.38
VI18 1.5-2.0 15 21.1912 22.1940 1.0028 22.1738 0.9826 22.1112 0.9200 0.0626 6.37
VI18 2.0-2.5 37 20.6017 21.6014 0.9997 21.5800 0.9783 21.5142 0.9125 0.0658 6.73
VI18 2.5-3.0 16 20.3333 21.3380 1.0047 21.3059 0.9726 21.2359 0.9026 0.0700 7.20
VI18 3.0-3.5 34 21.1801 22.1829 1.0028 22.1481 0.9680 22.0692 0.8891 0.0789 8.15
VI18 3.5-4.0 21 21.0367 22.0336 0.9969 21.9943 0.9576 21.9182 0.8815 0.0761 7.95
VI18 4.0-4.5 14 20.1812 21.1859 1.0047 21.1479 0.9667 21.0745 0.8933 0.0734 7.59
VI18 4.5-5.0 17 18.4190 19.4141 0.9951 19.3899 0.9709 19.3133 0.8943 0.0766 7.89
VI18 5.0-5.5 40 17.4613 18.4641 1.0028 18.4561 0.9948 18.4214 0.9601 0.0347 3.49
VI18 7.0-8.0 BS 28 20.4615 21.4690 1.0075 21.4306 0.9691 21.3314 0.8699 0.0992 10.24
VI18 8.0-9.0 BS 19 20.1577 21.1551 0.9974 21.1192 0.9615 21.0303 0.8726 0.0889 9.25
RUP03TRIS 5.5-6.0 55 17.5665 18.5644 0.9979 18.5195 0.9530 18.4426 0.8761 0.0769 8.07
RUP03TRIS 6.0-6.5 67 17.7577 18.7513 0.9936 18.7105 0.9528 18.6257 0.8680 0.0848 8.90
RUP03TRIS 6.5-7.0 17 18.4205 19.4296 1.0091 19.3875 0.9670 19.3053 0.8848 0.0822 8.50
RUP03TRIS 7.0-7.5 36 17.8248 18.8247 0.9999 18.7760 0.9512 18.7022 0.8774 0.0738 7.76
RUP03TRIS 7.5-8.0 37 20.6021 21.6101 1.0080 21.5641 0.9620 21.4824 0.8803 0.0817 8.49
74
RUP03TRIS 8.0-8.5 59 17.2007 18.2084 1.0077 18.1650 0.9643 18.0745 0.8738 0.0905 9.39
RUP03TRIS 8.5-9.0 31 21.3409 22.3497 1.0088 22.2956 0.9547 22.2217 0.8808 0.0739 7.74
RUP03TRIS 9.0-9.5 62 20.7083 21.7025 0.9942 21.6491 0.9408 21.5705 0.8622 0.0786 8.35
RUP03TRIS 9.5-10.0 Not enough sample material
RUP03TRIS 10.0-10.5 28 20.4611 21.4674 1.0063 21.4127 0.9516 21.3347 0.8736 0.0780 8.20
RUP03TRIS 10.5-11.0 10 17.0973 18.0956 0.9983 18.0418 0.9445 17.9655 0.8682 0.0763 8.08
RUP03TRIS 11.0-11.5 11 19.7442 20.7434 0.9992 20.6907 0.9465 20.6103 0.8661 0.0804 8.49
RUP03TRIS 11.5-12.0 46 18.6421 19.6034 0.9613 19.5540 0.9119 19.4767 0.8346 0.0773 8.48
RUP03TRIS 12.0-12.5 58 17.6251 18.6292 1.0041 18.5802 0.9551 18.5023 0.8772 0.0779 8.16
RUP03TRIS 12.5-13.0 21 21.0361 22.0357 0.9996 21.9857 0.9496 21.9111 0.8750 0.0746 7.86
RUP03TRIS 13.0-13.5 47 17.7779 18.7725 0.9946 18.7257 0.9478 18.6494 0.8715 0.0763 8.05
RUP03TRIS 13.5-14.0 78 18.0544 19.0562 1.0018 19.0125 0.9581 18.9349 0.8805 0.0776 8.10
RUP03TRIS 14.0-14.5 2 17.7388 18.7331 0.9943 18.6896 0.9508 18.6139 0.8751 0.0757 7.96
RUP03TRIS 14.5-15.0 34 21.1802 22.1829 1.0027 22.1269 0.9467 22.0468 0.8666 0.0801 8.46
RUP03TRIS 15.0-15.5 14 20.1814 21.1844 1.0030 21.1168 0.9354 21.0349 0.8535 0.0819 8.76
RUP03TRIS 17.0-18.0 BS 56 20.6397 21.6331 0.9934 21.5822 0.9425 21.5053 0.8656 0.0769 8.16
RUP03TRIS 18.0-19.0 BS 3 17.7997 18.7914 0.9917 18.7646 0.9649 18.7176 0.9179 0.0470 4.87
VI8 0.0-0.5 Not enough sample material
VI8 0.5-1.0 Not enough sample material
VI8 1.0-1.5 Not enough sample material
VI8 3.0-4.0 BS 44 16.9822 17.9867 1.0045 17.9337 0.9515 17.8597 0.8775 0.0740 7.78
VI8 4.0-5.0 BS 61 20.9539 21.9539 1.0000 21.8935 0.9396 21.8119 0.8580 0.0816 8.68
VI8 11.5-12.0 18 (a) 18.2669 19.2676 1.0007 19.2275 0.9606 19.1456 0.8787 0.0819 8.53
VI8 12.0-12.5 39 20.1064 21.1094 1.0030 21.0659 0.9595 20.9677 0.8613 0.0982 10.23
VI8 12.5-13.0 6 18.2218 19.2222 1.0004 19.1793 0.9575 19.0797 0.8579 0.0996 10.40
VI8 13.0-13.5 68 20.8528 21.8586 1.0058 21.8128 0.9600 21.7131 0.8603 0.0997 10.39
75
VI8 13.5-14.0 9 20.8090 21.8064 0.9974 21.7613 0.9523 21.6582 0.8492 0.1031 10.83
VI8 14.0-14.5 43 18.4380 19.4377 0.9997 19.3971 0.9591 19.2997 0.8617 0.0974 10.16
VI8 14.5-15.0 49 20.4075 21.4020 0.9945 21.3566 0.9491 21.2560 0.8485 0.1006 10.60
VI8 15.0-15.5 1 17.9031 18.9061 1.0030 18.8881 0.9850 18.8221 0.9190 0.0660 6.70
VI8 15.5-16.0 45 17.8147 18.8173 1.0026 18.7809 0.9662 18.6948 0.8801 0.0861 8.91
VI8 19.0-20.0 BS 33 21.0927 22.0972 1.0045 22.0550 0.9623 21.9665 0.8738 0.0885 9.20
VI8 20.0-21.0 BS 72 21.0053 22.0035 0.9982 21.9594 0.9541 21.8706 0.8653 0.0888 9.31
CB9 1.1-2.1 BS 35 19.8732 20.8778 1.0046 20.8534 0.9802 20.7938 0.9206 0.0596 6.08
CB9 2.1-3.1 BS 29 21.6753 22.6766 1.0013 22.6458 0.9705 22.5665 0.8912 0.0793 8.17
CB9 18.9-19.9 41 21.1071 22.1026 0.9955 22.0895 0.9824 22.0517 0.9446 0.0378 3.85
CB9 19.9-20.9 18 (b) 20.1275 21.1248 0.9973 21.1068 0.9793 21.0571 0.9296 0.0497 5.08
CB9 20.9-21.9 52 18.2706 19.2767 1.0061 19.2613 0.9907 19.2095 0.9389 0.0518 5.23
CB9 21.9-22.9 12 18.6025 19.6066 1.0041 19.5933 0.9908 19.5422 0.9397 0.0511 5.16
CB9 22.9-23.9 32 21.6010 22.6036 1.0026 22.5893 0.9883 22.5383 0.9373 0.0510 5.16
CB9 23.9-24.9 8 16.6928 17.6953 1.0025 17.6845 0.9917 17.6345 0.9417 0.0500 5.04
CB9 24.9-25.9 20 21.3197 22.3200 1.0003 22.3040 0.9843 22.2545 0.9348 0.0495 5.03
CB9 25.9-26.9 4 20.6923 21.6931 1.0008 21.6798 0.9875 21.6314 0.9391 0.0484 4.90
CB9 26.9-27.9 23 19.1817 20.1812 0.9995 20.1557 0.9740 20.0990 0.9173 0.0567 5.82
CB9 27.9-28.9 26 19.6371 20.6398 1.0027 20.6159 0.9788 20.5501 0.9130 0.0658 6.72
CB9 28.9-29.9 24 21.4584 22.4527 0.9943 22.4257 0.9673 22.3614 0.9030 0.0643 6.65
CB9 29.9-30.9 60 17.5537 18.5529 0.9992 18.5326 0.9789 18.4698 0.9161 0.0628 6.42
CB9 30.9-31.9 38 18.6963 19.6954 0.9991 19.6725 0.9762 19.6096 0.9133 0.0629 6.44 Leaf fragments
CB9 31.9-32.9 57 18.0440 19.0419 0.9979 19.0302 0.9862 18.9831 0.9391 0.0471 4.78
CB9 32.9-33.9 25 19.3763 20.3795 1.0032 20.3674 0.9911 20.3257 0.9494 0.0417 4.21
CB9 33.9-34.9 13 17.1102 18.1153 1.0051 18.1067 0.9965 18.0685 0.9583 0.0382 3.83 Coarse wood + leaf material
CB9 34.9-35.9 64 19.8098 20.8036 0.9938 20.7908 0.9810 20.7595 0.9497 0.0313 3.19 Coarse wood + leaf material
76
RUP02BIS 5.0-6.0 BS 16 20.3331 21.3377 1.0046 21.2881 0.9550 21.2057 0.8726 0.0824 8.63
RUP02BIS 12.0-13.0 BS 54 18.5414 19.5433 1.0019 19.5003 0.9589 19.4167 0.8753 0.0836 8.72
RUP02BIS 14.5-15.5 50 21.0732 22.0745 1.0013 22.0253 0.9521 21.9253 0.8521 0.1000 10.50
RUP02BIS 19.5-20.5 5 20.4288 21.4265 0.9977 21.3872 0.9584 21.2825 0.8537 0.1047 10.92
RUP02BIS 24.5-25.5 66 20.8440 21.8426 0.9986 21.7844 0.9404 21.6422 0.7982 0.1422 15.12
RUP02BIS 29.5-30.5 22 20.7103 21.7197 1.0094 21.6664 0.9561 21.5228 0.8125 0.1436 15.02
RUP02BIS 34.5-35.5 40 17.4615 18.4607 0.9992 18.4070 0.9455 18.2802 0.8187 0.1268 13.41
RUP02BIS 39.5-40.5 65 19.5920 20.5949 1.0029 20.5447 0.9527 20.4146 0.8226 0.1301 13.66
RUP02BIS 44.5-45.5 70 21.5770 22.5739 0.9969 22.5423 0.9653 22.3883 0.8113 0.1540 15.95
RUP02BIS 49.5-50.5 51 20.6904 21.6966 1.0062 21.6569 0.9665 21.4907 0.8003 0.1662 17.20
RUP02BIS 54.5-55.5 75 21.1027 22.1066 1.0039 22.0574 0.9547 21.8977 0.7950 0.1597 16.73
RUP02BIS 59.5-60.5 79 20.6995 21.6985 0.9990 21.6553 0.9558 21.4983 0.7988 0.1570 16.43
RUP02BIS 64.5-65.5 48 16.7092 17.7052 0.9960 17.6658 0.9566 17.5071 0.7979 0.1587 16.59
RUP02BIS 69.5-70.5 73 21.2595 22.2541 0.9946 22.2153 0.9558 22.0557 0.7962 0.1596 16.70
RUP02BIS 74.5-75.5 74 20.7692 21.7618 0.9926 21.7205 0.9513 21.5671 0.7979 0.1534 16.13
RUP02BIS 79.5-80.5 69 20.4485 21.4492 1.0007 21.4121 0.9636 21.2551 0.8066 0.1570 16.29
VI4 0.0-0.5 Not enough sample material
VI4 0.5-1.0 Not enough sample material
VI4 1.0-1.5 Not enough sample material
VI4 3.0-4.0 BS 53 18.7953 19.7922 0.9969 19.7903 0.9950 19.7039 0.9086 0.0864 8.68
VI4 4.0-5.0 BS 44 16.9828 17.9904 1.0076 17.9889 1.0061 17.8911 0.9083 0.0978 9.72
VI4 9.0-9.5 70 21.5769 22.5804 1.0035 22.5773 1.0004 22.4916 0.9147 0.0857 8.57
VI4 9.5-10.0 6 18.2224 19.2263 1.0039 19.2249 1.0025 19.1256 0.9032 0.0993 9.91
VI4 10.0-10.5 30 17.5177 18.5124 0.9947 18.5110 0.9933 18.4095 0.8918 0.1015 10.22
VI4 10.5-11.0 57 18.0446 19.0441 0.9995 19.0395 0.9949 18.9386 0.8940 0.1009 10.14
VI4 19.0-20.0 BS 64 19.8093 20.8059 0.9966 20.8041 0.9948 20.7327 0.9234 0.0714 7.18
VI4 20.0-21.0 BS 74 20.7685 21.7648 0.9963 21.7656 0.9971 21.6843 0.9158 0.0813 8.15
77
RI5 7.5-8.0 49 20.4068 21.4007 0.9939 21.4003 0.9935 21.3057 0.8989 0.0946 9.52
RI5 8.0-8.5 27 20.4964 21.4994 1.0030 21.4956 0.9992 21.4049 0.9085 0.0907 9.08
RI5 8.5-9.0 3 17.8014 18.8047 1.0033 18.8009 0.9995 18.7118 0.9104 0.0891 8.91
RI5 9.0-9.5 21 21.0378 22.0333 0.9955 22.0259 0.9881 21.9343 0.8965 0.0916 9.27
RI5 9.5-10.0 68 20.8530 21.8532 1.0002 21.8414 0.9884 21.7513 0.8983 0.0901 9.12
RI5 10.0-10.5 56 20.6398 21.6382 0.9984 21.6343 0.9945 21.5448 0.9050 0.0895 9.00
RI5 10.5-11.0 36 17.8253 18.8257 1.0004 18.8175 0.9922 18.7204 0.8951 0.0971 9.79
RI5 11.0-11.5 78 18.0552 19.0543 0.9991 19.0464 0.9912 18.9437 0.8885 0.1027 10.36 Wood + leaf fragments
RI5 11.5-12.0 45 17.8161 18.8151 0.9990 18.8126 0.9965 18.7065 0.8904 0.1061 10.65 Wood + leaf fragments
RI5 12.0-12.5 79 20.6997 21.6957 0.9960 21.6873 0.9876 21.5826 0.8829 0.1047 10.60
RI5 12.5-13.0 48 16.7105 17.7202 1.0097 17.7148 1.0043 17.6016 0.8911 0.1132 11.27
RI5 13.0-13.5 14 20.1821 21.1878 1.0057 21.1776 0.9955 21.0578 0.8757 0.1198 12.03
RI5 13.5-14.0 73 21.2598 22.2588 0.9990 22.2511 0.9913 22.1324 0.8726 0.1187 11.97
RI5 14.0-14.5 67 17.7584 18.7520 0.9936 18.7451 0.9867 18.6226 0.8642 0.1225 12.42
RI5 14.5-15.0 5 20.4300 21.4355 1.0055 21.4211 0.9911 21.3058 0.8758 0.1153 11.63
RI5 15.0-15.5 19 20.1591 21.1547 0.9956 21.1444 0.9853 21.0412 0.8821 0.1032 10.47
RI5 17.0-18.0 BS 63 21.0377 22.0385 1.0008 22.0329 0.9952 21.9423 0.9046 0.0906 9.10
RI5 18.0-19.0 BS 37 20.6018 21.6087 1.0069 21.5895 0.9877 21.4987 0.8969 0.0908 9.19
RI7 0.0-0.5 15 21.1919 22.1977 1.0058 22.1783 0.9864 22.0376 0.8457 0.1407 14.26
RI7 0.5-1.0 20 21.3199 22.3120 0.9921 22.2985 0.9786 22.1485 0.8286 0.1500 15.33
RI7 1.0-1.5 76 21.8171 22.8217 1.0046 22.8086 0.9915 22.6415 0.8244 0.1671 16.85
RI7 1.5-2.0 25 19.3765 20.3757 0.9992 20.3668 0.9903 20.1985 0.8220 0.1683 16.99
RI7 2.0-2.5 71 17.9715 18.9721 1.0006 18.9622 0.9907 18.8369 0.8654 0.1253 12.65
RI7 2.5-3.0 33 21.0929 22.0986 1.0057 22.0834 0.9905 22.0057 0.9128 0.0777 7.84
RI7 5.0-6.0 BS 55 17.5675 18.5623 0.9948 18.5498 0.9823 18.4481 0.8806 0.1017 10.35
RI7 6.0-7.0 BS 11 19.7443 20.7422 0.9979 20.7225 0.9782 20.6379 0.8936 0.0846 8.65
RI7 10.5-11.0 77 21.4111 22.4138 1.0027 22.4029 0.9918 22.2756 0.8645 0.1273 12.84
78
RI7 11.0-11.5 47 17.7786 18.7756 0.9970 18.7629 0.9843 18.6407 0.8621 0.1222 12.41
RI7 11.5-12.0 51 20.6900 21.6908 1.0008 21.6739 0.9839 21.5562 0.8662 0.1177 11.96
RI712.0-12.5 52 18.2712 19.2746 1.0034 19.2629 0.9917 19.1358 0.8646 0.1271 12.82
RI7 12.5-13.0 39 20.1059 21.1060 1.0001 21.0875 0.9816 20.9596 0.8537 0.1279 13.03
RI7 13.0-13.5 8 16.6941 17.6991 1.0050 17.6921 0.9980 17.5559 0.8618 0.1362 13.65 Coarse wood + leaf material
RI7 13.5-14.0 9 20.8096 21.8060 0.9964 21.7968 0.9872 21.7238 0.9142 0.0730 7.39 Coarse wood + leaf material
RI7 14.0-14.5 69 20.4483 21.4472 0.9989 21.4387 0.9904 21.3582 0.9099 0.0805 8.13
RI7 15.5-16.5 BS 41 21.1076 22.1024 0.9948 22.0869 0.9793 21.9781 0.8705 0.1088 11.11
RI7 16.5-17.5 BS 34 21.1808 22.1826 1.0018 22.1697 0.9889 22.0665 0.8857 0.1032 10.44
79
2. RESULTS BULK GEOCHEMICAL ANALYSIS
Sample ID δ13C (‰) C Amount (µg)
δ15N (‰) N Amount (µg)
Measured weights (mg)
TOC (%) TN (%) C/N
RUP02BIS 5.0-6.0 BS -31.31 1258.95 -0.09 106.51 35.284 3.568 0.302 11.820
RUP02BIS 12.0-13.0 BS -29.65 1149.86 -0.07 90.83 35.401 3.248 0.257 12.659
RUP02BIS 14.5-15.5 -27.05 1135.17 0.89 78.02 30.777 3.688 0.254 14.549
RUP02BIS 19.5-20.5 -26.90 1022.24 0.39 64.27 27.104 3.772 0.237 15.906
RUP02BIS 24.5-25.5 -27.19 1066.73 0.34 68.80 18.200 5.861 0.378 15.504
RUP02BIS 29.5-30.5 -27.02 1076.08 0.30 67.08 18.398 5.849 0.365 16.041
RUP02BIS 34.5-35.5 -27.17 1292.78 0.21 82.34 23.146 5.585 0.356 15.700
RUP02BIS 39.5-40.5 -27.12 1210.34 0.20 76.88 22.530 5.372 0.341 15.743
RUP02BIS 44.5-45.5 -27.23 1026.69 0.15 65.83 18.221 5.635 0.361 15.597
RUP02BIS 49.5-50.5 -27.30 947.33 0.13 62.20 15.197 6.234 0.409 15.230
RUP02BIS 54.5-55.5 -27.25 1044.41 0.18 68.80 16.989 6.148 0.405 15.180
RUP02BIS 59.5-60.5 -27.30 1146.30 0.02 74.08 18.406 6.228 0.402 15.474
RUP02BIS 64.5-65.5 -27.21 999.90 0.09 64.76 16.832 5.940 0.385 15.439
RUP02BIS 69.5-70.5 -27.26 1036.64 0.18 66.95 17.494 5.926 0.383 15.483
RUP02BIS 74.5-75.5 -27.15 974.54 0.09 62.42 16.750 5.818 0.373 15.613
RUP02BIS 79.5-80.5 -27.18 1072.55 0.18 71.26 18.427 5.821 0.387 15.051
RUP04 6.3-7.3 -28.02 1468.79 -1.92 88.14 17.840 8.233 0.494 16.663
RUP04 7.3-8.3 -28.11 1135.31 -1.66 69.16 16.082 7.060 0.430 16.415
RUP04 8.3-9.3 -27.94 1172.44 -1.61 69.96 16.584 7.070 0.422 16.758
RUP04 9.3-10.3 -28.30 1291.32 -1.44 78.33 15.596 8.280 0.502 16.487
RUP04 10.3-11.3 -28.13 1341.84 -1.33 83.33 16.751 8.011 0.497 16.103
RUP04 11.3-12.3 -28.11 1179.46 -1.61 71.99 16.562 7.122 0.435 16.385
RUP04 12.3-13.3 -28.17 1256.86 -1.52 74.64 17.394 7.226 0.429 16.839
RUP04 13.3-14.3 -28.06 1227.91 -1.71 71.71 17.478 7.025 0.410 17.123
RUP04 14.3-15.3 -28.27 1101.62 -1.40 69.18 19.266 5.718 0.359 15.923
RUP04 15.3-16.3 -28.29 1109.30 -1.60 68.91 16.530 6.711 0.417 16.098
RUP04 16.3-17.3 -28.23 1385.58 -1.66 82.02 18.592 7.453 0.441 16.894
RUP04 17.3-18.3 -28.26 1354.65 -1.59 85.45 20.931 6.472 0.408 15.853
RUP04 18.3-19.3 -28.21 1206.71 -0.86 85.31 35.959 3.356 0.237 14.146
RUP04 21.0-22.0 BS -28.86 1196.52 -0.19 99.19 20.886 5.729 0.475 12.063
RUP04 22.0-23.0 BS -28.98 1188.61 -0.34 99.19 23.428 5.073 0.423 11.983
CALA05 0.0-0.5 -29.21 863.63 2.19 109.33 25.913 3.333 0.422 7.899
CALA05 1.0-1.5 -29.98 817.31 2.15 108.11 23.658 3.455 0.457 7.560
CALA05 3.0-4.0 BS -29.77 676.82 2.07 90.51 27.786 2.436 0.326 7.478
CALA05 4.0-5.0 BS -30.12 640.48 2.23 84.66 22.862 2.802 0.370 7.565
CALA05 6.5-7.0 -29.40 794.53 2.15 92.56 19.846 4.003 0.466 8.584
CALA05 7.0-7.5 -29.13 1006.33 1.55 116.44 37.173 2.707 0.313 8.643
CALA05 7.5-8.0 -28.85 1041.68 1.45 128.41 39.081 2.665 0.329 8.112
CALA05 8.0-8.5 -29.01 771.17 1.33 93.99 28.332 2.722 0.332 8.204
CALA05 8.5-9.0 -29.01 825.05 1.46 102.65 30.721 2.686 0.334 8.038
CALA05 9.0-9.5 -29.10 889.65 1.21 100.49 30.729 2.895 0.327 8.853
CALA05 9.5-10.0 -29.16 1000.15 0.64 124.51 34.129 2.930 0.365 8.032
CALA05 10.0-10.5 -29.05 1040.94 1.15 113.21 34.715 2.999 0.326 9.195
CALA05 10.5-11.0 -29.33 821.99 1.74 95.51 42.545 1.932 0.224 8.606
CALA05 13.0-14.0 BS -29.93 723.70 1.61 89.36 21.937 3.299 0.407 8.099
CALA05 14.0-15.0 BS -30.42 758.28 1.10 94.68 24.680 3.072 0.384 8.009
CB9 1.1-2.1 BS -31.07 678.34 1.80 74.53 23.135 2.932 0.322 9.101
CB9 2.1-3.1 BS -29.12 967.29 1.84 100.41 41.424 2.335 0.242 9.634
CB9 18.9-19.9 -29.41 364.75 1.77 44.61 39.421 0.925 0.113 8.177
CB9 19.9-20.9 -28.79 415.39 1.08 41.30 29.437 1.411 0.140 10.057
80
CB9 20.9-21.9 -28.74 514.04 1.48 52.70 35.019 1.468 0.150 9.754
CB9 21.9-22.9 -28.60 579.29 1.20 53.05 35.635 1.626 0.149 10.919
CB9 22.9-23.9 -28.66 659.76 1.51 64.92 41.354 1.595 0.157 10.163
CB9 23.9-24.9 -28.65 677.34 1.43 63.84 42.541 1.592 0.150 10.610
CB9 24.9-25.9 -28.74 689.05 1.37 63.17 41.659 1.654 0.152 10.908
CB9 25.9-26.9 -28.85 717.50 1.40 73.49 50.997 1.407 0.144 9.763
CB9 26.9-27.9 -29.08 621.78 1.40 69.54 32.230 1.929 0.216 8.941
CB9 27.9-28.9 -29.07 683.19 1.50 76.20 33.449 2.042 0.228 8.966
CB9 28.9-29.9 -28.94 691.11 1.53 73.37 30.236 2.286 0.243 9.420
CB9 29.9-30.9 -29.12 717.45 1.72 79.96 34.413 2.085 0.232 8.972
CB9 30.9-31.9 -28.93 1025.78 1.22 110.15 53.938 1.902 0.204 9.312
CB9 31.9-32.9 -28.90 820.16 1.38 82.35 62.556 1.311 0.132 9.959
CB9 32.9-33.9 -28.73 1090.26 1.08 98.52 62.951 1.732 0.157 11.066
CB9 33.9-34.9 -28.70 446.18 3.22 45.73 61.903 0.721 0.074 9.757
CB9 34.9-35.9 -28.80 499.83 1.31 49.69 60.505 0.826 0.082 10.059
CGC1 21.1-21.6 -27.98 240.91 1.48 20.70 59.430 0.405 0.035 11.640
CGC1 21.6-22.1 -28.06 176.52 2.60 13.91 61.739 0.286 0.023 12.693
CGC1 22.1-22.6 -27.93 188.85 2.45 22.53 59.915 0.315 0.038 8.383
CGC1 22.6-23.1 -28.02 257.79 2.30 19.56 61.346 0.420 0.032 13.177
CGC1 23.1-23.6 -28.38 348.08 1.11 25.29 59.332 0.587 0.043 13.766
CGC1 23.6-24.1 -28.13 246.35 2.15 18.62 64.843 0.380 0.029 13.230
CGC1 24.1-24.6 -28.11 270.95 1.55 24.64 63.595 0.426 0.039 10.996
CGC1 24.6-25.0 -28.14 279.57 2.20 19.92 61.530 0.454 0.032 14.037
CGC1 2.0-3.0 BS -29.20 1069.01 1.20 97.43 43.109 2.480 0.226 10.973
CGC1 3.0-4.0 BS -29.21 1126.68 1.50 104.29 36.767 3.064 0.284 10.803
RI8 8.7-9.2 -28.54 1016.39 1.77 99.16 32.261 3.151 0.307 10.250
RI8 9.2-9.7 -28.62 1121.80 1.79 105.83 32.540 3.447 0.325 10.601
RI8 9.7-10.2 -28.63 1085.71 1.86 102.61 31.521 3.444 0.326 10.581
RI8 10.2-10.7 -28.60 1024.64 1.76 100.09 30.441 3.366 0.329 10.237
RI8 10.7-11.2 -28.64 1075.82 1.70 103.81 32.138 3.348 0.323 10.364
RI8 11.7-12.2 -28.68 1172.14 1.65 112.02 35.306 3.320 0.317 10.464
RI8 12.2-12.7 -28.65 1210.88 1.88 114.08 36.019 3.362 0.317 10.614
RI8 12.7-13.2 -28.57 1112.93 1.87 101.80 31.803 3.499 0.320 10.932
RI8 13.2-13.7 -28.39 1307.61 1.38 106.25 32.962 3.967 0.322 12.307
RI8 13.7-14.2 -28.50 1042.51 1.26 78.43 24.675 4.225 0.318 13.292
RI8 14.2-14.7 -28.24 1406.02 0.05 94.79 26.391 5.328 0.359 14.832
RI8 14.7-14.9 -27.90 985.91 1.25 57.77 36.908 2.671 0.157 17.067
RI8 16.0-17.0 BS -29.12 1049.11 1.60 100.33 31.112 3.372 0.322 10.456
RI8 22.0-23.0 BS -30.01 872.43 0.60 86.96 38.655 2.257 0.225 10.033
CALA08 0.5-1.5 -28.37 1128.22 1.36 97.93 54.664 2.064 0.179 11.521
CALA08 1.5-2.5 -28.18 1232.72 1.37 99.99 54.695 2.254 0.183 12.329
CALA08 2.5-3.5 -28.16 1147.97 1.33 90.78 50.423 2.277 0.180 12.646
CALA08 3.5-4.5 -28.34 1257.45 1.42 100.46 53.542 2.349 0.188 12.516
CALA08 4.5-5.5 -28.22 1064.18 1.76 86.50 45.925 2.317 0.188 12.302
CALA08 5.5-6.5 -28.32 1197.30 1.21 96.22 47.165 2.539 0.204 12.444
CALA08 6.5-7.5 -28.32 1189.06 1.63 94.34 46.088 2.580 0.205 12.604
CALA08 7.5-8.5 -28.58 1097.71 1.44 90.96 44.636 2.459 0.204 12.068
CALA08 8.5-9.5 -28.57 1306.17 1.29 107.94 59.555 2.193 0.181 12.101
CALA08 9.5-10.5 -28.55 1206.41 1.49 99.72 57.892 2.084 0.172 12.098
CALA08 10.5-11.5 -28.71 1231.56 1.67 101.90 52.517 2.345 0.194 12.086
CALA08 11.5-12.0 -28.96 1041.05 1.74 91.15 60.775 1.713 0.150 11.422
CALA08 14.0-15.0 BS -29.80 709.78 1.15 79.70 24.557 2.890 0.325 8.905
CALA08 15.0-16.0 BS -30.15 917.18 1.61 105.74 29.430 3.116 0.359 8.674
CB4 1.2-2.2 BS -29.57 919.88 1.72 92.42 29.947 3.072 0.309 9.954
81
CB4 2.2-3.2 BS -28.70 1077.87 1.75 102.98 34.918 3.087 0.295 10.467
CB4 14.8-15.3 -28.61 876.30 1.30 81.00 60.308 1.453 0.134 10.818
CB4 15.8-16.3 -28.33 1096.61 0.97 88.00 59.736 1.836 0.147 12.461
CB4 16.3-16.8 -28.51 1040.42 0.84 83.21 51.568 2.018 0.161 12.504
CB4 16.8-17.3 -28.59 1320.55 0.90 109.75 62.113 2.126 0.177 12.032
CB4 17.3-17.8 -28.57 1226.02 0.83 101.87 59.082 2.075 0.172 12.035
CB4 17.8-18.3 -28.55 1024.94 1.16 83.44 46.946 2.183 0.178 12.283
CB4 18.3-18.8 -28.53 1058.04 0.98 89.70 49.819 2.124 0.180 11.795
CB4 18.8-19.3 -28.30 1220.18 0.84 96.18 47.030 2.594 0.204 12.687
CB4 19.3-19.8 -28.95 1739.75 0.15 102.16 42.663 4.078 0.239 17.029
CB4 19.8-20.3 -28.44 1209.12 0.03 82.11 33.684 3.590 0.244 14.725
CB4 20.3-20.8 -28.10 1167.84 0.34 92.30 61.707 1.893 0.150 12.653
CB4 20.8-21.3 -28.79 1042.08 0.95 84.74 55.231 1.887 0.153 12.297
VI18 0.0-0.5 -29.94 1181.66 1.09 126.85 39.238 3.012 0.323 9.315
VI18 0.5-1.0 -28.40 661.01 0.76 57.99 27.240 2.427 0.213 11.400
VI18 1.0-1.5 -28.01 904.42 0.77 67.89 34.154 2.648 0.199 13.321
VI18 1.5-2.0 -27.91 1486.10 0.74 107.00 57.059 2.604 0.188 13.889
VI18 2.0-2.5 -27.93 1407.53 0.89 104.38 54.266 2.594 0.192 13.484
VI18 2.5-3.0 -27.95 1386.95 1.58 131.12 51.054 2.717 0.257 10.578
VI18 3.0-3.5 -27.99 1264.62 1.72 110.48 39.925 3.167 0.277 11.446
VI18 3.5-4.0 -27.96 1031.91 1.95 91.62 31.783 3.247 0.288 11.262
VI18 4.0-4.5 -28.05 1370.11 2.08 120.51 42.151 3.250 0.286 11.369
VI18 4.5-5.0 -27.94 1018.75 1.80 87.13 34.659 2.939 0.251 11.692
VI18 5.0-5.5 -28.25 816.42 1.96 74.71 63.502 1.286 0.118 10.928
VI18 7.0-8.0 BS -28.07 1052.97 1.56 109.91 31.747 3.317 0.346 9.580
VI18 8.0-9.0 BS -28.25 849.94 1.32 83.41 24.288 3.499 0.343 10.190
RUP03TRIS 5.5-6.0 -28.85 633.39 0.77 66.48 23.554 2.689 0.282 9.528
RUP03TRIS 6.0-6.5 -28.63 571.44 0.56 61.24 22.459 2.544 0.273 9.331
RUP03TRIS 6.5-7.0 -28.68 557.96 0.76 58.88 21.406 2.607 0.275 9.476
RUP03TRIS 7.0-7.5 -28.81 598.25 0.34 62.53 21.950 2.726 0.285 9.567
RUP03TRIS 7.5-8.0 -28.75 705.77 0.25 73.84 24.935 2.830 0.296 9.558
RUP03TRIS 8.0-8.5 -28.90 811.55 0.28 77.73 25.357 3.201 0.307 10.441
RUP03TRIS 8.5-9.0 -28.86 805.88 0.22 78.64 26.508 3.040 0.297 10.247
RUP03TRIS 9.0-9.5 -28.67 738.18 0.46 75.02 25.254 2.923 0.297 9.840
RUP03TRIS 10.0-10.5 -28.79 979.16 0.36 87.25 29.064 3.369 0.300 11.222
RUP03TRIS 10.5-11.0 -28.85 788.42 0.35 77.51 24.571 3.209 0.315 10.172
RUP03TRIS 11.0-11.5 -28.73 727.65 0.27 75.50 24.507 2.969 0.308 9.637
RUP03TRIS 12.0-12.5 -28.79 791.69 0.31 79.55 26.215 3.020 0.303 9.953
RUP03TRIS 12.5-13.0 -28.85 798.29 0.29 85.11 27.133 2.942 0.314 9.380
RUP03TRIS 13.0-13.5 -28.90 899.52 0.17 89.80 30.986 2.903 0.290 10.017
RUP03TRIS 13.5-14.0 -28.67 833.16 0.13 83.20 27.699 3.008 0.300 10.014
RUP03TRIS 14.0-14.5 -28.85 767.02 0.27 78.21 26.946 2.847 0.290 9.808
RUP03TRIS 15.0-15.5 -28.93 770.02 0.79 75.09 23.359 3.296 0.321 10.254
RUP03TRIS 17.0-18.0 BS -29.40 712.13 0.28 77.85 24.851 2.866 0.313 9.148
RUP03TRIS 18.0-19.0 BS -29.43 691.20 -0.37 75.91 41.447 1.668 0.183 9.105
VI8 0.0-0.5 -29.72 675.70 2.69 82.31 17.695 3.819 0.465 8.209
VI8 0.5-1.0 -28.98 634.47 2.51 75.17 16.505 3.844 0.455 8.440
VI8 1.0-1.5 -29.12 729.92 2.69 85.39 17.311 4.217 0.493 8.548
VI8 3.0-4.0 BS -28.12 717.79 2.10 86.29 23.358 3.073 0.369 8.318
VI8 4.0-5.0 BS -28.25 992.22 2.34 111.65 29.638 3.348 0.377 8.887
VI8 11.5-12.0 -27.54 1316.05 1.75 108.31 32.574 4.040 0.333 12.150
VI8 12.0-12.5 -27.41 1460.49 1.64 112.94 31.496 4.637 0.359 12.931
VI8 12.5-13.0 -27.33 1487.62 1.77 116.81 30.590 4.863 0.382 12.735
VI8 13.0-13.5 -27.43 1377.74 1.58 112.00 29.914 4.606 0.374 12.301
82
VI8 13.5-14.0 -27.69 1470.33 1.65 117.79 30.541 4.814 0.386 12.482
VI8 14.0-14.5 -27.49 1778.83 1.43 119.14 29.676 5.994 0.401 14.930
VI8 14.5-15.0 -27.38 1488.41 1.64 103.39 28.253 5.268 0.366 14.396
VI8 15.0-15.5 -27.53 1105.53 2.30 103.55 55.702 1.985 0.186 10.676
VI8 15.5-16.0 -27.68 1059.30 2.65 107.66 33.176 3.193 0.325 9.840
VI8 19.0-20.0 BS -28.10 1003.45 2.38 105.04 32.155 3.121 0.327 9.553
VI8 20.0-21.0 BS -28.29 696.46 2.05 72.83 21.374 3.258 0.341 9.562
VI4 0.0-0.5 -29.02 746.88 2.73 80.11 16.466 4.536 0.486 9.324
VI4 0.5-1.0 -28.42 646.06 2.51 73.43 15.858 4.074 0.463 8.799
VI4 1.0-1.5 -28.52 886.55 2.84 91.39 20.349 4.357 0.449 9.701
VI4 3.0-4.0 BS -27.76 915.31 2.49 99.09 26.534 3.450 0.373 9.237
VI4 4.0-5.0 BS -28.25 1184.27 2.33 121.10 30.599 3.870 0.396 9.779
VI4 9.0-9.5 -27.38 1016.21 2.67 101.25 31.177 3.259 0.325 10.037
VI4 9.5-10.0 -27.26 1178.35 2.60 106.41 31.571 3.732 0.337 11.074
VI4 10.0-10.5 -27.15 1316.53 2.40 111.36 32.067 4.106 0.347 11.822
VI4 10.5-11.0 -27.21 1165.17 2.35 104.35 29.592 3.937 0.353 11.166
VI4 19.0-20.0 BS -27.79 1078.53 2.08 115.59 38.735 2.784 0.298 9.330
VI4 20.0-21.0 BS -27.77 897.38 1.98 98.31 30.617 2.931 0.321 9.128
RI5 7.5-8.0 -28.38 1154.49 1.20 97.03 30.613 3.771 0.317 11.898
RI5 8.0-8.5 -28.54 1195.53 1.26 112.03 35.026 3.413 0.320 10.671
RI5 8.5-9.0 -28.52 1174.52 1.23 110.09 34.136 3.441 0.323 10.669
RI5 9.0-9.5 -28.57 1087.90 1.20 102.70 32.401 3.358 0.317 10.593
RI5 9.5-10.0 -28.62 1117.99 1.26 104.37 32.336 3.457 0.323 10.712
RI5 10.0-10.5 -28.59 1169.27 1.28 109.33 32.561 3.591 0.336 10.695
RI5 10.5-11.0 -28.67 1133.13 1.38 103.22 31.103 3.643 0.332 10.977
RI5 11.0-11.5 -28.57 1103.92 1.23 97.85 29.064 3.798 0.337 11.282
RI5 11.5-12.0 -28.42 1103.57 1.12 93.85 27.503 4.013 0.341 11.759
RI5 12.0-12.5 -28.53 1181.25 1.11 101.83 30.304 3.898 0.336 11.600
RI5 12.5-13.0 -28.20 1468.29 0.91 103.16 28.773 5.103 0.359 14.233
RI5 13.0-13.5 -28.24 1361.25 0.75 93.25 26.550 5.127 0.351 14.597
RI5 13.5-14.0 -28.17 1276.58 0.65 90.83 23.993 5.321 0.379 14.054
RI5 14.0-14.5 -28.31 1122.78 1.03 82.91 22.828 4.918 0.363 13.543
RI5 14.5-15.0 -28.30 1271.63 1.08 98.57 27.622 4.604 0.357 12.901
RI5 15.0-15.5 -28.48 1238.19 1.31 103.03 29.110 4.253 0.354 12.018
RI5 17.0-18.0 BS -28.92 1225.17 1.38 118.48 33.133 3.698 0.358 10.341
RI5 18.0-19.0 BS -29.04 1349.42 0.92 120.40 32.690 4.128 0.368 11.207
RI7 0.0-0.5 -28.77 1250.96 1.63 90.37 20.069 6.233 0.450 13.843
RI7 0.5-1.0 -28.75 1488.06 1.22 98.07 18.029 8.254 0.544 15.174
RI7 1.0-1.5 -28.57 1084.70 1.12 73.23 15.612 6.948 0.469 14.811
RI7 1.5-2.0 -28.60 1174.58 1.00 74.42 16.168 7.265 0.460 15.783
RI7 2.0-2.5 -28.50 1711.24 0.49 103.44 24.072 7.109 0.430 16.544
RI7 2.5-3.0 -29.15 1066.92 2.21 94.23 29.314 3.640 0.321 11.323
RI7 5.0-6.0 BS -29.45 1126.77 1.83 118.16 28.148 4.003 0.420 9.536
RI7 6.0-7.0 BS -29.78 789.07 1.60 81.25 22.268 3.544 0.365 9.712
RI7 10.5-11.0 -28.13 1113.50 1.01 70.88 21.203 5.252 0.334 15.710
RI7 11.0-11.5 -28.12 1259.69 0.97 84.18 25.297 4.980 0.333 14.964
RI7 11.5-12.0 -28.20 1209.11 1.11 79.75 27.163 4.451 0.294 15.160
RI7 12.0-12.5 -28.25 1210.10 0.78 80.26 22.556 5.365 0.356 15.077
RI7 12.5-13.0 -28.09 937.12 0.97 57.61 21.736 4.311 0.265 16.268
RI7 13.0-13.5 -28.10 1184.17 0.48 65.60 21.151 5.599 0.310 18.051
RI7 13.5-14.0 -27.69 2277.95 0.35 87.18 43.150 5.279 0.202 26.130
RI7 14.0-14.5 -27.76 1955.47 0.57 96.58 41.342 4.730 0.234 20.246
RI7 15.5-16.5 BS -28.69 1124.71 1.80 97.02 25.167 4.469 0.386 11.593
83
3. RESULTS GRAIN SIZE ANALYSIS
Sample name Sample type Textural group Sediment name Mean (µm) Sorting Skewness Kurtosis
CALA05 0.0-0.5 Polymodal, Very Poorly Sorted Mud Fine Silt 7.066 4.054 0.111 0.892
CALA05 1.0-1.5 Trimodal, Very Poorly Sorted Mud Very Fine Silt 6.113 4.088 0.189 1.059
CALA05 3.0-4.0 BS Unimodal, Poorly Sorted Mud Very Fine Silt 5.198 3.191 0.140 1.026
CALA05 4.0-5.0 BS Unimodal, Poorly Sorted Mud Fine Silt 5.304 3.210 0.101 1.013
CALA05 6.5-7.0 Trimodal, Very Poorly Sorted Mud Very Fine Silt 4.075 4.388 0.088 1.008
CALA05 7.0-7.5 Polymodal, Very Poorly Sorted Mud Very Fine Silt 7.207 4.421 0.072 0.861
CALA05 7.5-8.0 Polymodal, Very Poorly Sorted Mud Fine Silt 9.210 4.295 0.004 0.789
CALA05 8.0-8.5 Polymodal, Very Poorly Sorted Mud Very Fine Silt 8.149 4.250 0.059 0.810
CALA05 8.5-9.0 Trimodal, Poorly Sorted Mud Fine Silt 10.11 3.927 0.041 0.757
CALA05 9.0-9.5 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Fine Silt 9.250 4.747 0.048 0.764
CALA05 9.5-10.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Fine Silt 10.16 5.180 0.034 0.772
CALA05 10.0-10.5 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Fine Silt 10.86 5.103 0.015 0.779
CALA05 10.5-11.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 31.81 5.725 -0.447 0.746
CALA05 13.0-14.0 BS Trimodal, Poorly Sorted Mud Very Fine Silt 5.682 3.694 0.153 1.010
CALA05 14.0-15.0 BS Trimodal, Poorly Sorted Mud Very Fine Silt 4.258 3.644 0.125 1.091
CALA08 0.5-1.5 Trimodal, Poorly Sorted Mud Medium Silt 8.833 2.923 -0.061 0.902
CALA08 1.5-2.5 Trimodal, Poorly Sorted Mud Coarse Silt 10.81 2.836 -0.143 0.944
CALA08 2.5-3.5 Trimodal, Poorly Sorted Mud Coarse Silt 11.87 2.829 -0.155 0.979
CALA08 3.5-4.5 Trimodal, Poorly Sorted Mud Coarse Silt 11.98 2.781 -0.166 0.995
CALA08 4.5-5.5 Trimodal, Poorly Sorted Mud Coarse Silt 12.11 2.741 -0.178 0.999
CALA08 5.5-6.5 Trimodal, Poorly Sorted Mud Coarse Silt 11.36 2.748 -0.181 0.995
CALA08 6.5-7.5 Trimodal, Poorly Sorted Mud Coarse Silt 11.24 2.738 -0.184 0.995
CALA08 7.5-8.5 Bimodal, Poorly Sorted Mud Coarse Silt 13.24 2.870 -0.180 1.032
CALA08 8.5-9.5 Bimodal, Poorly Sorted Mud Coarse Silt 16.71 2.946 -0.228 1.011
CALA08 9.5-10.5 Bimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 18.94 3.050 -0.216 1.000
CALA08 10.5-11.5 Trimodal, Poorly Sorted Mud Coarse Silt 16.93 3.044 -0.191 0.997
84
CALA08 11.5-12.0 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 24.17 2.769 -0.284 1.069
CALA08 14.0-15.0 BS Bimodal, Poorly Sorted Mud Fine Silt 6.325 3.122 0.008 0.956
CALA08 15.0-16.0 BS Unimodal, Poorly Sorted Mud Fine Silt 5.443 3.083 0.033 1.012
CB4 1.2-2.2 BS Bimodal, Poorly Sorted Mud Medium Silt 7.895 2.913 -0.091 0.961
CB4 2.2-3.2 BS Bimodal, Poorly Sorted Mud Medium Silt 7.430 3.075 -0.079 0.997
CB4 14.8-15.3 Unimodal, Poorly Sorted Mud Fine Silt 4.708 3.024 0.057 1.067
CB4 15.3-15.8 Trimodal, Poorly Sorted Mud Medium Silt 11.29 2.949 -0.119 0.976
CB4 15.8-16.3 Trimodal, Poorly Sorted Mud Medium Silt 11.85 3.024 -0.130 0.972
CB4 16.3-16.8 Trimodal, Poorly Sorted Mud Medium Silt 12.58 3.377 -0.046 0.991
CB4 16.8-17.3 Bimodal, Poorly Sorted Mud Medium Silt 10.88 3.173 -0.038 1.000
CB4 17.3-17.8 Bimodal, Poorly Sorted Mud Medium Silt 10.72 3.240 -0.024 1.011
CB4 17.8-18.3 Trimodal, Poorly Sorted Sandy Mud Very Fine Sandy Medium Silt 12.67 3.838 0.059 1.075
CB4 18.3-18.8 Bimodal, Poorly Sorted Mud Medium Silt 10.84 3.187 -0.019 1.033
CB4 18.8-19.3 Bimodal, Poorly Sorted Mud Medium Silt 11.53 3.491 0.007 1.058
CB4 19.3-19.8 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Medium Silt 15.73 4.406 0.098 0.985
CB4 19.8-20.3 Bimodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Medium Silt 15.39 4.067 0.043 0.925
CB4 20.3-20.8 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 33.63 5.419 -0.137 0.847
CB4 20.8-21.3 Polymodal, Very Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 49.62 5.857 -0.209 0.854
CB9 1.1-2.1 BS Trimodal, Poorly Sorted Mud Fine Silt 6.973 3.059 -0.022 0.903
CB9 2.1-3.1 BS Polymodal, Very Poorly Sorted Sandy Mud Fine Sandy Medium Silt 10.18 4.198 0.111 1.073
CB9 18.9-19.9 Bimodal, Poorly Sorted Mud Very Fine Silt 6.143 3.700 0.267 1.057
CB9 19.9-20.9 Bimodal, Poorly Sorted Mud Fine Silt 8.845 2.987 0.028 0.919
CB9 20.9-21.9 Polymodal, Poorly Sorted Mud Medium Silt 9.945 3.066 -0.028 0.918
CB9 21.9-22.9 Trimodal, Poorly Sorted Mud Medium Silt 10.29 3.003 -0.069 0.928
CB9 22.9-23.9 Trimodal, Poorly Sorted Mud Medium Silt 10.67 3.013 -0.105 0.949
CB9 23.9-24.9 Trimodal, Poorly Sorted Mud Coarse Silt 11.61 2.953 -0.161 0.941
CB9 24.9-25.9 Trimodal, Poorly Sorted Mud Coarse Silt 11.33 3.027 -0.153 0.950
CB9 25.9-26.9 Bimodal, Poorly Sorted Mud Coarse Silt 13.80 3.166 -0.236 0.925
CB9 26.9-27.9 Polymodal, Very Poorly Sorted Sandy Mud Fine Sandy Coarse Silt 18.32 5.029 -0.021 0.860
CB9 27.9-28.9 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 12.63 4.856 0.055 0.909
85
CB9 28.9-29.9 Polymodal, Poorly Sorted Mud Fine Silt 8.467 3.750 0.013 0.880
CB9 29.9-30.9 Polymodal, Poorly Sorted Mud Fine Silt 10.15 3.983 -0.002 0.837
CB9 30.9-31.9 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 13.34 4.452 -0.100 0.775
CB9 31.9-32.9 Polymodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 32.23 3.977 -0.462 1.091
CB9 32.9-33.9 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 37.37 4.094 -0.484 1.123
CB9 33.9-34.9 Bimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 51.44 3.420 -0.436 1.437
CB9 34.9-35.9 Trimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 55.40 3.659 -0.413 1.352
CGC1 2.0-3.0 BS Bimodal, Poorly Sorted Mud Medium Silt 8.557 2.968 -0.033 0.974
CGC1 3.0-4.0 BS Trimodal, Poorly Sorted Mud Medium Silt 10.68 3.577 0.039 1.139
CGC1 21.1-21.6 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 39.36 2.264 -0.214 1.147
CGC1 21.6-22.1 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 44.13 2.208 -0.228 1.149
CGC1 22.6-23.1 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 48.84 2.220 -0.262 1.207
CGC1 23.1-23.6 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 52.84 2.166 -0.257 1.243
CGC1 23.6-24.1 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 47.84 2.214 -0.286 1.285
CGC1 24.1-24.6 Unimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 57.65 2.299 -0.335 1.392
CGC1 24.6-25.0 Unimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 64.57 2.372 -0.318 1.388
RI5 7.5-8.0 Polymodal, Very Poorly Sorted Mud Very Fine Silt 8.369 4.109 0.079 0.796
RI5 8.0-8.5 Trimodal, Poorly Sorted Mud Very Fine Silt 7.451 3.712 0.150 0.830
RI5 8.5-9.0 Polymodal, Poorly Sorted Mud Very Fine Silt 6.584 3.795 0.128 0.855
RI5 9.0-9.5 Polymodal, Poorly Sorted Mud Very Fine Silt 7.060 3.978 0.113 0.841
RI5 9.5-10.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Fine Silt 11.43 5.185 0.129 0.826
RI5 10.0-10.5 Polymodal, Poorly Sorted Mud Fine Silt 8.098 3.897 0.117 0.844
RI5 10.5-11.0 Polymodal, Very Poorly Sorted Mud Fine Silt 8.517 4.107 0.073 0.819
RI5 11.0-11.5 Polymodal, Very Poorly Sorted Mud Fine Silt 9.367 4.252 0.059 0.800
RI5 11.5-12.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 9.403 4.273 0.056 0.803
RI5 12.0-12.5 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 10.26 4.104 0.016 0.781
RI5 12.5-13.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 15.81 4.443 -0.196 0.783
RI5 13.0-13.5 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 23.75 3.729 -0.355 0.960
RI5 13.5-14.0 Bimodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 22.67 4.169 -0.302 0.898
RI5 14.0-14.5 Trimodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 18.79 4.162 -0.282 0.834
86
RI5 14.5-15.0 Bimodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 23.41 4.003 -0.305 0.892
RI5 15.0-15.5 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 15.21 4.611 -0.154 0.766
RI5 17.0-18.0 BS Bimodal, Poorly Sorted Mud Fine Silt 6.535 3.359 0.105 0.924
RI5 18.0-19.0 BS Trimodal, Poorly Sorted Mud Fine Silt 6.876 3.618 0.098 0.899
RI7 0.0-0.5 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 25.26 3.981 -0.337 0.932
RI7 0.5-1.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 19.76 4.320 -0.261 0.834
RI7 1.0-1.5 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 21.09 4.571 -0.291 0.824
RI7 1.5-2.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 25.93 4.523 -0.321 0.866
RI7 2.0-2.5 Bimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 50.35 3.741 -0.382 1.114
RI7 2.5-3.0 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 31.80 4.979 -0.432 0.836
RI7 5.0-6.0 BS Bimodal, Poorly Sorted Mud Fine Silt 6.698 3.598 0.188 0.951
RI7 6.0-7.0 BS Polymodal, Poorly Sorted Mud Fine Silt 5.680 3.331 0.091 0.943
RI7 10.5-11.0 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 27.67 3.490 -0.311 1.026
RI7 11.0-11.5 Trimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 23.36 3.958 -0.320 0.946
RI7 11.5-12.0 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 26.87 3.698 -0.299 1.075
RI7 12.0-12.5 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 27.65 3.758 -0.307 1.022
RI7 12.5-13.0 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 27.65 3.889 -0.303 1.016
RI7 13.0-13.5 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 45.33 3.476 -0.248 1.143
RI7 13.5-14.0 Unimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 64.40 2.956 -0.199 1.183
RI7 14.0-14.5 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 50.42 3.439 -0.279 1.128
RI7 15.5-16.5 BS Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 10.62 4.126 0.064 0.829
RI7 16.5-17.5 BS Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 13.93 4.062 -0.167 0.780
RI8 8.7-9.2 Trimodal, Poorly Sorted Mud Very Fine Silt 6.700 3.511 0.108 0.845
RI8 9.2-9.7 Polymodal, Poorly Sorted Mud Very Fine Silt 6.421 3.756 0.114 0.872
RI8 9.7-10.2 Polymodal, Poorly Sorted Mud Very Fine Silt 6.670 3.684 0.087 0.883
RI8 10.2-10.7 Trimodal, Poorly Sorted Mud Fine Silt 6.891 3.631 0.097 0.879
RI8 10.7-11.2 Polymodal, Poorly Sorted Mud Very Fine Silt 6.731 3.738 0.086 0.886
RI8 11.7-12.2 Polymodal, Very Poorly Sorted Mud Very Fine Silt 7.002 4.079 0.123 0.901
RI8 12.2-12.7 Polymodal, Very Poorly Sorted Mud Very Fine Silt 8.087 4.224 0.106 0.861
RI8 12.7-13.2 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 10.52 4.385 0.061 0.788
87
RI8 13.2-13.7 Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 12.43 4.721 -0.037 0.735
RI8 14.2-14.7 Bimodal, Very Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 44.69 4.029 -0.406 1.179
RI8 14.7-14.9 Trimodal, Poorly Sorted Muddy Sand Very Coarse Silty Very Fine Sand 73.46 3.208 -0.385 1.315
RI8 16.0-17.0 BS Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 8.051 4.347 0.193 0.981
RI8 22.0-23.0 BS Trimodal, Poorly Sorted Mud Very Fine Silt 3.894 3.241 0.120 1.275
RUP02BIS 5.0-6.0 BS Bimodal, Poorly Sorted Mud Medium Silt 9.921 3.044 -0.093 0.971
RUP02BIS 12.0-13.0 BS Bimodal, Poorly Sorted Mud Medium Silt 9.854 3.001 -0.041 0.983
RUP02BIS 14.5-15.5 Trimodal, Poorly Sorted Mud Fine Silt 6.862 3.055 -0.019 0.948
RUP02BIS 19.5-20.5 Trimodal, Poorly Sorted Mud Medium Silt 12.19 3.190 -0.080 0.960
RUP02BIS 24.5-25.5 Bimodal, Poorly Sorted Mud Medium Silt 8.079 2.755 -0.100 0.977
RUP02BIS 29.5-30.5 Bimodal, Poorly Sorted Mud Medium Silt 8.390 2.689 -0.125 0.980
RUP02BIS 34.5-35.5 Bimodal, Poorly Sorted Mud Medium Silt 9.322 2.880 -0.101 1.008
RUP02BIS 39.5-40.5 Bimodal, Poorly Sorted Mud Medium Silt 9.958 2.984 -0.095 0.994
RUP02BIS 44.5-45.5 Bimodal, Poorly Sorted Mud Medium Silt 9.016 2.859 -0.113 0.994
RUP02BIS 49.5-50.5 Bimodal, Poorly Sorted Mud Medium Silt 8.016 2.749 -0.128 0.983
RUP02BIS 54.5-55.5 Bimodal, Poorly Sorted Mud Medium Silt 8.193 2.796 -0.117 0.998
RUP02BIS 59.5-60.5 Bimodal, Poorly Sorted Mud Medium Silt 8.346 2.833 -0.103 1.020
RUP02BIS 64.5-65.5 Bimodal, Poorly Sorted Mud Medium Silt 7.885 2.693 -0.155 0.965
RUP02BIS 69.5-70.5 Bimodal, Poorly Sorted Mud Medium Silt 8.412 2.771 -0.125 0.990
RUP02BIS 74.5-75.5 Bimodal, Poorly Sorted Mud Medium Silt 8.859 2.807 -0.129 0.986
RUP02BIS 79.5-80.5 Bimodal, Poorly Sorted Mud Medium Silt 8.784 2.811 -0.128 0.997
RUP03TRIS 10.5-11.0 Bimodal, Poorly Sorted Mud Medium Silt 10.19 3.532 0.036 0.937
RUP03TRIS 11.0-11.5 Trimodal, Poorly Sorted Mud Fine Silt 8.149 3.373 0.036 0.968
RUP03TRIS 12.0-12.5 Trimodal, Poorly Sorted Mud Fine Silt 8.456 3.651 0.024 0.967
RUP03TRIS 12.5-13.0 Trimodal, Poorly Sorted Mud Fine Silt 8.719 3.693 0.038 0.969
RUP03TRIS 13.0-13.5 Trimodal, Poorly Sorted Mud Medium Silt 9.457 3.888 0.039 0.940
RUP03TRIS 13.5-14.0 Polymodal, Poorly Sorted Mud Fine Silt 8.658 3.915 0.022 0.953
RUP03TRIS 14.0-14.5 Bimodal, Poorly Sorted Mud Medium Silt 9.770 3.954 0.039 0.928
RUP03TRIS 15.0-15.5 Trimodal, Poorly Sorted Mud Medium Silt 10.67 3.397 -0.020 0.949
RUP03TRIS 5.5-6.0 Bimodal, Poorly Sorted Mud Fine Silt 7.814 3.243 0.042 0.929
88
RUP03TRIS 6.0-6.5 Trimodal, Poorly Sorted Mud Fine Silt 7.926 3.247 0.006 0.970
RUP03TRIS 6.5-7.0 Bimodal, Poorly Sorted Mud Fine Silt 7.580 3.078 0.007 0.979
RUP03TRIS 7.0-7.5 Trimodal, Poorly Sorted Mud Fine Silt 7.603 3.336 0.004 0.979
RUP03TRIS 7.5-8.0 Bimodal, Poorly Sorted Mud Fine Silt 7.039 3.320 -0.009 0.972
RUP03TRIS 8.0-8.5 Bimodal, Poorly Sorted Mud Fine Silt 7.471 3.434 0.011 0.956
RUP03TRIS 8.5-9.0 Bimodal, Poorly Sorted Mud Medium Silt 7.978 3.439 -0.002 0.969
RUP03TRIS 9.0-9.5 Trimodal, Poorly Sorted Mud Fine Silt 7.100 3.478 0.017 0.974
RUP03TRIS 9.5-10.0 Bimodal, Poorly Sorted Mud Fine Silt 7.326 3.480 0.021 0.969
RUP03TRIS 17.0-18.0 BS Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Fine Silt 11.45 4.366 0.126 0.950
RUP03TRIS 18.0-19.0 BS Polymodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 27.64 5.286 -0.222 0.819
RUP04 6.3-7.3 Bimodal, Poorly Sorted Mud Coarse Silt 15.59 3.026 -0.216 0.977
RUP04 7.3-8.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 19.36 2.985 -0.211 1.074
RUP04 8.3-9.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 19.55 2.966 -0.260 1.019
RUP04 9.3-10.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 18.56 3.012 -0.227 1.001
RUP04 10.3-11.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 18.84 3.072 -0.235 1.004
RUP04 11.3-12.3 Bimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 17.81 3.071 -0.211 1.006
RUP04 12.3-13.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 20.93 3.009 -0.242 1.015
RUP04 13.3-14.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 24.41 3.028 -0.278 1.023
RUP04 14.3-15.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 25.32 3.042 -0.230 1.036
RUP04 15.3-16.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 25.65 3.405 -0.151 1.020
RUP04 16.3-17.3 Bimodal, Poorly Sorted Sandy Mud Very Fine Sandy Coarse Silt 21.07 3.079 -0.190 1.022
RUP04 17.3-18.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 22.69 3.155 -0.188 1.015
RUP04 18.3-19.3 Unimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 30.41 3.129 -0.279 1.004
RUP04 21.0-22.0 BS Trimodal, Poorly Sorted Mud Medium Silt 10.39 3.174 -0.135 0.954
RUP04 22.0-23.0 BS Trimodal, Poorly Sorted Mud Coarse Silt 11.33 3.293 -0.125 0.942
VI18 0.0-0.5 Polymodal, Very Poorly Sorted Sandy Mud Fine Sandy Very Fine Silt 7.196 4.792 0.255 1.069
VI18 0.5-1.0 Trimodal, Poorly Sorted Mud Medium Silt 11.03 3.157 -0.070 0.903
VI18 1.0-1.5 Polymodal, Poorly Sorted Mud Coarse Silt 14.48 2.985 -0.167 0.951
VI18 1.5-2.0 Trimodal, Poorly Sorted Mud Coarse Silt 15.92 2.956 -0.183 0.987
VI18 2.0-2.5 Trimodal, Poorly Sorted Mud Coarse Silt 15.23 2.982 -0.167 0.973
89
VI18 2.5-3.0 Trimodal, Poorly Sorted Mud Medium Silt 11.68 3.343 -0.070 0.927
VI18 3.0-3.5 Trimodal, Poorly Sorted Mud Medium Silt 9.392 3.288 -0.032 0.941
VI18 3.5-4.0 Bimodal, Poorly Sorted Mud Medium Silt 9.441 3.249 -0.035 0.957
VI18 4.0-4.5 Trimodal, Poorly Sorted Mud Medium Silt 9.893 3.464 -0.028 0.929
VI18 4.5-5.0 Polymodal, Poorly Sorted Mud Medium Silt 12.28 3.583 -0.068 0.889
VI18 5.0-5.5 Bimodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 33.02 3.120 -0.403 1.117
VI18 7.0-8.0 BS Trimodal, Poorly Sorted Mud Fine Silt 8.196 3.992 0.137 1.124
VI18 8.0-9.0 BS Bimodal, Poorly Sorted Mud Fine Silt 6.437 3.100 0.023 0.966
VI4 0.0-0.5 Polymodal, Very Poorly Sorted Mud Very Fine Silt 6.585 4.388 0.152 1.016
VI4 0.5-1.0 Trimodal, Poorly Sorted Mud Very Fine Silt 5.026 3.415 0.080 0.987
VI4 1.0-1.5 Polymodal, Poorly Sorted Mud Very Fine Silt 5.583 3.796 0.070 0.947
VI4 3.0-4.0 BS Trimodal, Poorly Sorted Mud Very Fine Silt 5.511 3.614 0.088 0.995
VI4 4.0-5.0 BS Trimodal, Poorly Sorted Mud Very Fine Silt 5.315 3.609 0.094 1.015
VI4 9.0-9.5 Polymodal, Poorly Sorted Mud Very Fine Silt 6.223 3.734 0.049 0.880
VI4 9.5-10.0 Polymodal, Poorly Sorted Mud Medium Silt 7.588 3.740 -0.072 0.885
VI4 10.0-10.5 Polymodal, Very Poorly Sorted Mud Coarse Silt 10.01 4.004 -0.152 0.842
VI4 10.5-11.0 Trimodal, Very Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 13.65 4.069 -0.238 0.826
VI4 20.0-21.0 BS Polymodal, Poorly Sorted Mud Very Fine Silt 5.382 3.885 0.117 1.021
VI8 0.0-0.5 Bimodal, Poorly Sorted Mud Very Fine Silt 4.279 3.245 0.131 1.138
VI8 0.5-1.0 Bimodal, Poorly Sorted Mud Fine Silt 5.187 3.389 0.091 1.039
VI8 1.0-1.5 Trimodal, Poorly Sorted Mud Very Fine Silt 4.347 3.296 0.066 1.054
VI8 3.0-4.0 BS Bimodal, Poorly Sorted Mud Fine Silt 4.610 3.188 0.066 1.105
VI8 4.0-5.0 BS Polymodal, Very Poorly Sorted Mud Fine Silt 5.851 4.363 0.212 1.301
VI8 11.5-12.0 Polymodal, Poorly Sorted Mud Fine Silt 5.501 3.299 -0.031 0.993
VI8 12.0-12.5 Polymodal, Very Poorly Sorted Sandy Mud Fine Sandy Fine Silt 7.065 4.652 0.166 1.183
VI8 12.5-13.0 Trimodal, Poorly Sorted Mud Fine Silt 5.645 3.409 -0.012 1.001
VI8 13.0-13.5 Trimodal, Poorly Sorted Mud Fine Silt 5.822 3.541 0.012 1.012
VI8 13.5-14.0 Polymodal, Poorly Sorted Mud Fine Silt 5.697 3.415 0.002 0.991
VI8 14.0-14.5 Polymodal, Poorly Sorted Mud Fine Silt 5.856 3.635 0.024 1.007
VI8 14.5-15.0 Trimodal, Very Poorly Sorted Mud Fine Silt 7.656 4.152 0.074 0.970
90
VI8 15.0-15.5 Polymodal, Poorly Sorted Sandy Mud Very Fine Sandy Very Coarse Silt 23.03 3.997 -0.408 0.834
VI8 15.5-16.0 Polymodal, Very Poorly Sorted Sandy Mud Fine Sandy Fine Silt 11.45 5.637 0.225 0.924
VI8 19.0-20.0 BS Bimodal, Poorly Sorted Mud Fine Silt 5.056 3.229 0.038 1.042
VI8 20.0-21.0 BS Bimodal, Poorly Sorted Mud Fine Silt 5.004 3.115 0.057 1.030