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Petroleum geology of South Australia Vol 2 Eromanga Basin 1

CHAPTER 7 Sequence stratigraphy

TB Cotton MF Scardigno and PJ Boult

INTRODUCTION 2

KEY CONCEPTS2

Accommodation space and sediment supply 2

Sequences and systems tracts2

Lowstand systems tract 3

Transgressive systems tract3 Highstand systems tract 3

POOLOWANNA FORMATION4

Stratigraphic traps4

HUTTON SANDSTONE 5

BIRKHEAD FORMATION6

Stratigraphic traps7

ADORI SANDSTONEWESTBOURNE FORMATION 7

NAMUR SANDSTONE 8

MURTA FORMATION 8

CADNA-OWIE FORMATION8

Wyandra Sandstone Member9

UPPER MARINE SUCCESSION9

FIGURES10



Chapter 7 Sequence Stratigraphy


INTRODUCTION

Sequence stratigraphy provides a basis for the chronostratigraphic correlation of sediments and a valuable

exploration and reservoir development tool for the petroleum industry A sequence stratigraphic approach to

correlation on both a regional and field-scale coupled with an understanding of depositional environments and the

roles of accommodation space and sediment supply can aid in the reconstruction of palaeogeography and

prediction of temporal and spatial relationships between source reservoir and seal facies While the concepts of

sequence stratigraphy have been readily applied to passive margin and foreland basin settings there has been

significantly less focus on their application to intra-cratonic and fluvial-dominated basins (Posamentier and Allen

1999 Lang et al 2001)

In the Eromanga Basin sequence stratigraphy has been applied sporadically on a field and regional scale within a

lithostratigraphic framework to better understand the relationships between and distribution of key depositional

facies The relatively dense well coverage throughout the Cooper region of the Eromanga Basin in both South

Australia and Queensland forms the basis for the correlation of geophysical well logs and delineation of systems

tracts on a regional scale (eg Lanzilli 1999) The availability of high-resolution 3D seismic over producing

Eromanga Basin petroleum fields and the resultant ability to visualise facies elements through such techniques as

seismic amplitude mapping have enabled the application of sequence stratigraphic concepts on a field scale toenhance reservoir development and delineate potential stratigraphic traps (eg Nakanishi and Lang 2002)

While there has been widespread recognition of major sequence boundaries and flooding surfaces within various

studies a complete detailed sequence stratigraphic study of the entire Eromanga Basin sequences has yet to be

undertaken One of the principal reasons for the limited application of sequence stratigraphy is that exploration has

been relatively successful without the need for detailed studies of sediment distribution (Lanzilli 1999) A sequence

stratigraphic approach to the correlation of Eromanga Basin sediments together with the reconstruction and

understanding of palaeo-depositional environments has potential to provide new exploration and development

opportunities within the basin

KEY CONCEPTSThis chapter aims to review recent studies that have incorporated the use of sequence stratigraphy to better

understand and predict the spatial distribution of sedimentary facies within the Eromanga Basin sequence For a

comprehensive account of sequence stratigraphic concepts and their application to fluviolacustrine depositional

systems the reader is directed to these relevant publications Posamentier and Allen 1999 Lang et al 2001

Nakanishi and Lang 2002 There is however a need within this discussion to provide a brief review of some of the

basic concepts and ideas pertaining to the application of sequence stratigraphy within a dominantly fluviolacustrine

depositional environment

Accommodation space and sediment supply

To understand the distribution of sedimentary facies within any basin it is critical to understand the interaction

between accommodation space and sediment supply Accommodation space in fluviolacustrine settings is the

space between the ground surface (subaerial or subaqueous) and the fluvial equilibrium profile (base level) to

which sediments will potentially fill or be eroded in the case of negative accommodation (Fig 71 Posamentier and

Allen 1999) In the Eromanga Basin where marine influence and hence eustatic fluctuation was restricted to the

Early Cretaceous the dominant controls on accommodation space were largely provided by tectonically driven

periods of subsidence and uplift together A generally low accommodation space persisted in the Eromanga Basin

The rate type and amount of sediment entering the basin were influenced by a combination of factors including

provenance climate and topographic relief

Sequences and systems t racts A lsquotypicalrsquo fluviolacustrine sequence comprises a relatively conformable succession of genetically related strata

bounded by regionally significant unconformities (Posamentier and Allen 1999 Lang et al 2001) In this context





the entire Eromanga Basin can be considered as a single low-order JurassicndashCretaceous (JndashK) lsquosequencersquo with

relatively continuous deposition of sediments from the Early Jurassic Poolowanna Formation to the Late

Cretaceous Winton Formation and bounded by regional unconformities (Fig 72) In addition to the basin bounding

unconformities breaks in sedimentation occurred locally throughout most lithostratigraphic intervals in response to

a variety factors Thus a pragmatic approach should allow numerous higher order sequences such as K1 K2 and

K3 (Fig 72) to be defined within localised areas of the basin and in turn the identification and correlation of time

equivalent strata on a variety of scales

The concept of a systems tract allows for the division of a stratigraphic sequence in turn allowing for the prediction

of lithofacies occurrences within the basin

Lowstand systems tract

Within non-marine sequences the lowstand systems tract typically forms above a sequence boundary after a

period of negative accommodation and erosion (Fig 73) With a slow rise in fluvial accommodation incised fluvial

valleys will be filled or alternatively fluvial channels and floodplain deposits reworked into sheets of laterally

amalgamated sand (Fig 74) In the Eromanga Basin extensive sand-rich lowstand deposits within the

Algebuckina Hutton and Namur sandstones form significant reservoirs Above the basal Eromanga Basinunconformity the lower Poolowanna Formation is also in part characterised by areas of amalgamated channel

sands and isolated narrow extensions suggestive of infilled palaeovalleys (Basin Studies Subprogram 1989

Draper 2002) However the lowstand Poolowanna Formation does not contain the laterally extensive sand sheets

of the overlying formations and suggests a restriction to topographically low areas as a result of increased

sediment supply following the Late Triassic ndash Early Jurassic depositional hiatus (Fig 72)

Transgressive systems tract

The transgressive systems tract represents a period of increasing accommodation relative to sediment supply and

is separated from the lowstand systems tract by a transgressive surface (Fig 73) As relative base level begins to

rise either through an increase in the rate of accommodation creation or through a drop in sediment supply fluvialchannels will become increasingly isolated within aggrading muddy floodplain deposits (Fig 74) The obvious

implications for petroleum exploration and development are that within the transgressive systems tract reservoir

quality frequency and interconnectivity will become increasingly reduced However there will be an increase in the

deposition of finer grained facies (potential seals) together with increased potential for stratigraphic trap

development Further increases in fluvial accommodation may result in formation of extensive peat mires within

cool-temperate climates and ultimately development of floodplain lakes and swamps (Fig 74 Lang et al 2001)

At the height of fluvial accommodation extensive lake systems may develop as was the case during deposition of

the Birkhead and Murta formations when widespread lacustrine facies were deposited across the Eromanga Basin

The Eromanga sequence is characterised by several periods where major rises in relative base level led to

deposition of sediment within low-energy swamp lacustrine and shallow marine environments Deposition of theBirkhead Formation and Murta Formation culminated in the formation of extensive lake systems and regionally

identifiable flooding surfaces A further rise in base level occurred in the Early Cretaceous associated with a

significant increase in global sea level (Veevers 1984 Lang et al 2001) and led to a prolonged period of marine

conditions until the Late Cretaceous During these periods of transgression sedimentation was largely

characterised by deposition of fine-grained silts and muds in low-energy environments There was however

significant development of clean well-sorted sands in both lacustrine and marine high-energy shoreline

environments where wind and wave reworking of sediment was able to take place These shoreline sandstones

form significant productive reservoirs in many oil fields across the Eromanga Basin

Highstand systems tract

The highstand systems tract represents deposition in a period of decreasing accommodation space and is

separated from the transgressive systems tract by a maximum flooding surface (Fig 73) The maximum flooding





surface represents the transition from increasing to decreasing available accommodation space as the rate of

sediment supply exceeds its creation In practical terms the maximum flooding surface is defined from gamma ray

logs as a maximum peak at the transition from the generally fining upward profile of the transgressive systems tract

to a generally coarsening upward profile of the highstand systems tract As base level rise slows either through

decreased subsidence or increased sediment supply fluvial channel deposits above retreating swamp or lake

deposits become progressively more clustered with higher net sand to gross thickness ratios (Fig 74 Lang et al

2001)

POOLOWANNA FORMATION

At the onset of Poolowanna Formation deposition lowstand and early transgressive systems tract sediments were

deposited within the topographic lows above a sequence boundary that developed during the preceding period of

uplift and erosion These basal Poolowanna deposits are characterised by sheet sands with gradually more

isolated fluvial channels crevasse-splay and floodplain deposits up section The upper Poolowanna Formation

becomes even finer grained and is dominated by floodplainndashcrevasse-splay deposits and isolated thin beds of coal

Thick amalgamated lowstand channel sequences were primarily deposited west of the Birdsville Track Ridge and

in the Poolowanna Trough where the formation reaches its maximum thickness Moreover the formation thicknessis typically greater on the hanging wall of growth faults In the eastern part of the Eromanga Basin where it overlies

the Cooper Basin the Poolowanna Formation was not deposited on palaeo-geographical highs including the

Innamincka Dome and the Murteree Ridge (Alexander and Sansome 1996 Boult 1996) but where present is

dominated by generally fining upward sequences consistent with deposition during a period of transgression

Nakanishi and Lang (2002) provided a sequence stratigraphic interpretation of the Poolowanna Formation in the

Moorari and Pondrinie fields (Figs 75 76) in which they divided the Poolowanna Formation into a lower and upper

section of a transgressive systems tract based upon facies distribution and their relationship to the sequence

boundary In the Moorari Field two sections are characterised by fluvial channel facies that change laterally into

crevasse-splay and floodplain facies (Fig 75) The lower section fills the incised topographic relief before channel

abandonment and development of a laterally continuous shale-prone interval Nakanishi and Lang (2002) interpret

this interval as a transgressive systems tract brought about by elevated base level rise The upper section contains

a series of thin upward coarsening floodplain and floodplainndashcrevasse-splay complex facies with thin coals and

sands This has been interpreted as a progradational highstand systems tract succession of a crevasse-splay delta

system infilling a relatively shallow floodplain lake The sequence coarsens up before another laterally continuous

shale-prone interval which is interpreted as a second transgressive systems tract overlying a flooding surface

Correlation of wells across the Pondrinie Field (Fig 76) shows a similar distribution of sediment to that seen in the

Moorari Field Laterally discontinuous fluvial channel and crevasse-splay facies are interpreted as infilling incised

topographic relief before the development of laterally continuous shale-prone or coaly intervals in response to a

rapid base level rise or channel avulsion

Stratigraphic traps

Based on 3D seismic data visualisation techniques and gamma ray well log motifs (Figs 77 78) Nakanishi and

Lang (2002) were able to define the distribution of sedimentary facies between intra-Poolowanna Formation

seismic horizons over the Moorari and Pondrinie fields The interpreted seismic facies were then used to identify

potential stratigraphic traps and risks associated with each play





In the Moorari 3D survey area the mapped intra-Poolowanna horizon (Fig 79) shows

bull A meandering channel morphology in the SW which has been interpreted as part of a fluvial channel belt

bull A combined channel and sheet-like seismic facies extending from the channel belt towards the middle of the

survey area representing a crevasse-splay channel ndash delta complex

bull A sheet-like seismic facies in the NE that is also interpreted as a crevasse-splay delta incised by the base of

the overlying Hutton Sandstone

In the Pondrinie 3D survey area the mapped intra-Poolowanna horizon (Fig 78) shows a NEndashSW-elongated

amplitude pattern with wedge-shaped tributary patterns that narrow on both sides Well log motifs and high-

amplitude distribution show that the thickest Poolowanna intervals coincide with areas of high amplitude and

suggest a main incised valley through the Pondrinie area with tributaries that enter along the sides

The lateral variation of reservoir and seal properties where channel belt facies thin and pinch out within floodplain

facies is one of the key potential stratigraphic trap opportunities within the Poolowanna Formation highlighted by

Nakanishi and Lang (2002) In both Moorari and Pondrinie areas fluvial sandstones have been concentrated and

preserved within the centres of incised valleys such that there is both a potential lateral seal provided by the

pinching out of the channel belt and a potential top seal provided by the laterally continuous shale-prone or coalyintervals related to flooding surfaces (Fig 710) Crevasse-splay delta complexes sealed by floodplain deposits

also provide potential stratigraphic traps within the Poolowanna Formation however the crevasse-splay delta

sandstones tend to be thin and Nakanishi and Lang (2002) suggest that interconnected crevasse channels could

provide higher permeability conduits to gather hydrocarbons from the crevasse-splay complex

One of the principal risks to the formation of both stratigraphic and structural traps within the Poolowanna

Formation is widespread incision by the overlying Hutton Sandstone (Lanzilli 1999 Nakanishi and Lang 2001a b

Nakanishi and Lang 2002) Visualisation of the Poolowanna Formation within the Moorari Field by Nakanishi and

Lang (2002 Fig 79) has highlighted the potential for poor lateral and top seal as a result of incision by Hutton

Sandstone channels (Fig 710) and is a possible reason for limited discoveries of commercial Poolowanna

Formation reservoirs across the Eromanga Basin

HUTTON SANDSTONE

Over much of the Eromanga Basin a drop in relative base level resulted in erosion incision into the Poolowanna

Formation and creation of a widespread sequence boundary With the onset of Hutton Sandstone deposition above

this boundary equilibrium was maintained between an increased rate of sedimentation as a result of tectonic uplift

in the southwestern source area (Boult 1996) and the rate of accommodation creation This established conditions

suitable for deposition of the thick laterally extensive amalgamated lowstand systems tract sandstones that form

the principal productive reservoirs throughout the Eromanga Basin

Initial interpretations of the Hutton Sandstone were that its upper boundary is gradational or intertongues with the

transgressive systems tract deposits of the Birkhead Formation (ie Solomon and Ormsby 1984 Yew and Mills

1989 Alexander and Sansome 1996) A regional sequence stratigraphic study of the Birkhead Formation by

Lanzilli (1999) concluded that a regional sequence boundary exists near the top of the Hutton Sandstone (as

defined by lithology Fig 711) formed in response to regional tilting and uplift associated with subduction at the

eastern margin of the Australian Plate Interpretation of 2D seismic lines in the Tindilpie area and 3D seismic at

Gidgealpa reveals a palaeo-landscape of flat-topped ridges up to 97 m high between the incised river valleys that

constitute the sequence boundary (Boult et al 1998)

The lithological pick of the top of the Hutton Sandstone often varies from the sequence boundary between the

Hutton and the Birkhead It is commonly picked in wells at the first encounter of significant sand beneath the finer

grained Birkhead facies which in many cases is actually top of the basal Birkhead lowstand systems tract The real





sequence boundary is often cryptic with sand-on-sand contact between the two formations typical in lowstand

braided successions (Miall and Arush 2001)

BIRKHEAD FORMATION

At the onset of Birkhead Formation deposition the provenance of Eromanga Basin sediments progressively shifted

from a Gawler Craton source in the SW to a volcanic-arc source on the east Australian continental margin (Fig

712 Boult 1996 Boult et al 1998 Lanzilli 1999) The Middle Jurassic Birkhead Formation comprises lowstand

transgressive and highstand systems tract facies (Fig 711) This is in contrast to the work of Nakanishi et al

(2003) who designated the entire Birkhead Formation sequence over the Merrimelia Meranji and Pelican fields

(Fig 13) as a transgressive systems tract due to the absence of laterally continuous stacked fluvial channels within

the valley fill (Fig 713) Where the lowstand systems tract is very sandy the lithological marker for the top Hutton

Sandstone is often interpreted at the transgressive surface But if the highstand systems tract is muddy then the

sequence boundary is used for the top Hutton Sandstone In the southwestern (South Australian) region of the

Eromanga Basin a lowstand systems tract is well developed at the base of the Birkhead Formation overlying the

basal Birkhead unconformity (Boult et al 1998) Meandering fluvial channels were deposited during a period of

increased sediment supply and filled the incised topographic relief above the regional sequence boundary (Lanzilli

1999 Fig 714)

In the southwestern (South Australian) region the early Birkhead Formation sediments were initially sourced from

the southwestern cratonic areas (Fig 712) In the eastern (Queensland) region the lowstand systems tract

consists of eroded and reworked Hutton Sandstone together with labile-rich volcanic arc derived (VAD) sediments

(Fig 712) These are locally missing over palaeohighs in more proximal areas due to continued uplift and erosion

but increasingly thicken towards the basin depocentre in the northeast (Boult et al 1998 Lanzilli 1999 Fig 711)

With continued erosion and influx of volcanic-arc-derived sediments from the east the main basin drainage outlet

to the north along the Euroka Arch (Fig 11) became ever more restricted (Lanzilli 1999 Fig 715) This in turn led

to a rise in base level and deposition of fine-grained and organic-rich sediments within a low-energy meandering

fluvial swampy deltaic to lacustrine environment (Fig 716) This rise in base level marks the transgressive surface

and onset of the transgressive systems tract The transgressive surface separates the transgressive systems tract

from the lowstand systems tracts where present and is coincident with the sequence boundary where early

Birkhead deposition did not occur (Lanzilli 1999 Fig 711)

The transgressive systems tract saw an influx of lithic-rich volcanic-arc-derived sediment from the east which

initially intertongued with the waning supply of southerly sourced cratonic sediments before extending over the SW

of the basin (Lanzilli 1999) A continued rise in base level resulting from decreasing sediment supply or increased

subsidence led to flooding and widespread deposition of deltaic and lacustrine facies of lsquoLake Birkheadrsquo When the

rate of base level rise reached its peak a maximum flooding surface developed This surface marks the limit of

transgression and the maximum landward extent of lacustrine conditions within the Eromanga Basin during

Birkhead time The maximum flooding surface is identifiable regionally across the basin as a high gamma ray

spike or alternatively a sonic spike indicating the presence of an organic-rich low-density condensed section

caused by sediment starvation in the basin depocentre (Lanzilli 1999)

In the later stages of the transgressive systems tract and into the early highstand systems tract uplift of the

cratonic area to the south and SW resulted in increased supply of cratonic-derived sediments towards the basin

depocentre Tectonism and subsequent tilting during mid Birkhead Formation time might have allowed Lake

Birkhead to once again drain out through the Euroka Arch (Lanzilli 1999) The increase in sediment supply and

decrease in lake level resulted in progradation of sandier deposits towards the basin centre with a resultant

coarsening up of the sedimentary profile (Fig 716) Lanzilli (1999) interpreted a sequence boundary at the top of

the Birkhead Formation on the basis of gamma ray and sonic curves that represent a sharp change to cleancemented braided fluvial sandstones and an absence of coals In the Merrimelia and Meranji fieldsrsquo area (Fig 13)





Nakanishi et al (2003) determined from seismic analysis that the top of the Birkhead Formation does not show

significant undulation and cannot be considered a significant erosional surface and sequence boundary

Stratigraphic traps

Nakanishi and Lang (2002) highlighted the potential for the formation of stratigraphic traps within the Birkhead

Formation through the identification of sedimentary facies and their distribution in the Merrimelia Meranji and

Pelican fields (Fig 13) Well logs combined with 3D seismic amplitude visualisation over the middle to upper part

of the formation indicate a well developed meandering fluvial channel system including point bars and abandoned

channels (Fig 717) Correlation of wells through the area show fluvial channels that pass laterally into crevasse-

splay and floodplain facies with laterally continuous shale-prone intervals identified as flooding surfaces (Nakanishi

et al 2003 Fig 713) Point bar sandstones within the channel belt were identified as potential stratigraphic

reservoirs where they are juxtaposed against fine-grained abandoned channel facies to provide a lateral seal

Intervals that are interpreted as shale from gamma ray logs may actually turn out to be high gamma siltstones or

sandstones upon core inspection rather than being potentially extensive top and bottom seals to reservoir facies

While point bar sandstones so far drilled within the Merrimelia Meranji and Pelican fields are known to be water

wet most reservoirs in the area are lt5 m thick and consist of crevasse-splay channel and crevasse-splay delta

facies The lateral thinning of sandstones into adjacent floodplain deposits combined with the probabledevelopment of widespread shaly intervals highlights the potential for the development of Birkhead Formation

stratigraphic traps elsewhere in the basin

In the Merrimelia Field oil accumulations exist in two discrete intervals a Hutton ndash basal Birkhead reservoir and a

middle Birkhead Formation reservoir Although the basal Birkhead reservoir is scattered a common oilndashwater

contact suggests that it acts within the HuttonndashBirkhead transition as a single reservoir The middle Birkhead

reservoir shows significant lateral facies change from sandstone to shale with thin coal beds Water-bearing

sandstones occur both above and below the reservoir interval and sands at the same depth level do not always

contain oil accumulations Consequently the oil pool in the mid Birkhead Formation can be considered as a

stratigraphic trap (Nakanishi and Lang 2002 Nakanishi et al 2003)

In the Dirkala and Dirkala South fields (Fig 13) Birkhead Formation reservoirs are restricted to fluvial channel

facies A lateral change from the channel fill facies to floodplain mudstone occurs up dip within structural closure

and causes a pinch-out stratigraphic trap and thus the reservoir has both a structural and stratigraphic component

(Mackie and Gumley 1995)

ADORI SANDSTONEWESTBOURNE FORMATION

The Adori Sandstone and Westbourne Formation represent a similar couplet to that of the Hutton Sandstone and

Birkhead Formation (Wiltshire 1989 Boult 1996) However both the Adori Sandstone and Westbourne Formation

are not as extensive and are restricted to the northern part of the Cooper region and eastern most Pedirka region in

South Australia (Alexander and Sansome 1996) Where the Westbourne Formation does not exist then the Adoriand Namur sandstones are amalgamated and the entire sequence is called the Namur Sandstone

The lower part of Adori Sandstone was deposited above a sequence boundary at the top of the Birkhead Formation

and predominantly consists of amalgamated braided fluvial sandstones that represent a lowstand systems tract

The sandstones higher in the formation become fine grained with a greater prevalence of siltstone and

carbonaceous material before a conformable transition into dark grey shale siltstone and minor sandstone

interbeds of the Westbourne Formation The AdorindashWestbourne lithostratigraphic boundary is defined from an

increase in gamma ray decrease in resistivity and slower sonic log values (Grey et al 2002) However from a

sequence stratigraphic perspective a transgressive systems tract can be defined from the onset of finer grained

facies in the Adori Sandstone to a maximum flooding surface within the lacustrine deposits of the upper

Westbourne Formation Depending on the location within the basin the maximum flooding surface may not be

preserved due to erosion and development of a widespread sequence boundary at the base of the overlying Namur

Sandstone (Gorter 1994) In areas where significant uplift occurred at the time of sequence boundary





development ie the Nebine Ridge that separates the Eromanga from Surat Basin (Fig 11) the Adori Sandstone

Westbourne Formation and upper Birkhead Formation may have all been eroded (Boult 1996)

NAMUR SANDSTONE

The Namur Sandstone consists of lowstand braided fluvial sandstones conformable on the Birkhead Formation

across most of the basin in South Australia and intertongues with the Westbourne Formation Gorter (1994) and

Theologou (1995) both interpreted a mid Namur Sandstone sequence boundary that represents incision into the

underlying mid Namur shale (Fig 718) However the development of a lsquomid Namur shalersquo related to a base level

rise as suggested by Theologou (1995) is uncertain due to only minor amounts of fine-grained sediment being

present in many wells across the basin Whether there is in fact a significant regional sequence boundary at the

mid Namur level is also unclear since it may instead be associated with the Westbourne Formation and since the

studies by both Gorter (1994) and Theologou (1995) were limited in their areal extent Also one of the key

arguments of Gorter for a sequence boundary was correlation with the 1285 Ma global sea level fall and any

marine influence within the intracratonic Eromanga Basin at that time has not been established Despite these

uncertainties what has been classified litho-stratigraphically as the Namur Sandstone can be considered as a

lowstand systems tract with transition to the meandering fluvial and lacustrine conditions of the McKinlay Member

and Murta Formation representing a rise in base level and onset of transgressive systems tract deposition

MURTA FORMATION

The Murta Formation was deposited in meandering fluvial floodplain and lacustrine environments and represents

an increase in fluvial accommodation and reduction in depositional energy from the lowstand braided fluvial

deposits of the underlying Namur Sandstone Theologou (1995) interpreted the transitional fine sandstone and

carbonaceous siltstone of the McKinlay Member which directly overlies the Namur Sandstone to be the onset of

the transgressive systems tract It was proposed by Theologou (1995) that the thickness trends of the McKinlay

Member represent the distribution of active Namur channels just prior to onset of transgression

Lang et al (2001) interpreted the Murta Formation at Maxwell in Queensland as consisting of two transgressivendash regressive cycles separated by a wave-ravinement surface (see Posamentier and Allen 1999 Lang et al 2001)

The wave-ravinement surface occurs within lacustrine shoreface sandstones and represents the change from

decreasing to increasing accommodation This can be seen on gamma ray logs as the onset of a retrogradational

stacking pattern (Fig 719) The two maximum flooding surfaces identified by Lang et al (2001) mark the boundary

between the transgressive and highstand systems tracts and can be seen on logs and in core as condensed

sections or hard grounds These markers can be recognised regionally in the Murta Formation across the

Eromanga Basin (Fig 718)

Zoellner (1988) and Gorter (1994) also interpreted the Murta Formation in South West Queensland as containing

two major transgressivendashregressive cycles however both authors suggested the presence of a sequence boundary

separating the two Gorter (1994) argued for the presence of a sequence boundary on the basis that sandstoneswithin the upper Murta Formation were in fact incised valley fill and constituted a lowstand systems tract (Fig 720)

CADNA-OWIE FORMATION

The lower part of the Cadna-owie Formation is conformable on the Murta Formation and marks the transition from

terrestrial to marine depositional environments with inundation occurring during the Early Cretaceous global sea

level rise The most significant marine influence is evident in sediments of the lower Cadna-owie Formation and a

peak in gamma ray log values across the basin shows a maximum flooding surface at the base of the succession

(Grey et al 2002) The maximum flooding surface marks the onset of the highstand systems tract and a period of

reduced accommodation that sees a steady decrease in gamma ray log values in wells across the basin In more

distal marine environments this decrease corresponds to the gradual change from mudstone and siltstonedeposition to siltstones and labile-rich sandstones deposited at the shoreface and on the coastal plain





Wyandra Sandstone Member

The upper part of the Cadna-owie Formation has been termed the Wyandra Sandstone Member with its base

defined by a regional sequence boundary overlain by amalgamated fluvial distributary channel fill (Fig 721 Lang

et al 2001) The sequence stratigraphy of the Wyandra Sandstone Member in Queensland was described by Lang

et al (2001) to comprise a lowstand systems tract that in-filled fluvial channels above the sequence boundary and

a transgressive systems tract marked by the deposition of tidally influenced sediments at the onset of a further

period of marine inundation (Fig 721) In the upper section of the Wyandra Sandstone Member two higher order

flooding sequences (Fig 721) are interpreted to represent sudden palaeo-bathymetric increases and are marked

by deposition of heterolithic marine strata in the increasingly distal depositional system (Lang et al 2001)

UPPER MARINE SUCCESSION

Following deposition of the Wyandra Sandstone Member continued subsidence created further marine

transgression and sufficient accommodation space for rapid accumulation of the thick fossiliferous mudstones and

siltstones of the Bulldog Shale and Wallumbilla Formation A maximum marine transgression was reached during

deposition of the mid to upper Bulldog Shale and equivalents and corresponds to global sea level maxima for that

time (Moussavi-Harami 1996) This maximum marine flooding surface can easily be recognised in wells across the

basin as the transition from increasing to decreasing gamma ray log values

Continued regression during deposition of the upper Bulldog Shale culminated in deposition of the Coorikiana

Sandstone in a shoreline environment Worldwide sea level again rose rapidly in the late Albian with deposition of

the main marine shales and mudstones of the upper Marree Subgroup (Moussavi-Harami 1996) While smaller

order cycles of transgression and regression can be identified within the upper Cretaceous sequence

sedimentation continued predominantly within marine and marginal marine environments until in the Late

Cretaceous when the region returned to terrestrial sedimentation and deposition of the fluviolacustrine Winton

Formation of the upper Marree Subgroup The Eromanga Basin fill culminates with the Winton Formation which is

unconformably overlain by Tertiary sediments of the Lake Eyre Basin





FIGURES

71 Schematic representation of positive and negative fluvial accommodation (a b) Illustrate an equilibrium

profile that corresponds to base level with no net erosion or deposition of sediment (c) A fall in equilibrium

profile resulting in erosion of sediment (d) A rise in the equilibrium profile resulting in aggradation of

sediment (After Posamentier and Allen 1999)

72 Generalised stratigraphic column and sequences of the Cooper Eromanga and Lake Eyre basins (afterMoussavi-Harami 1996)

73 Alluvial sequence stratigraphic model illustrating alluvial lowstand (LST) transgressive (TST) and

highstand (HST) systems tracts Key surfaces shown which separate systems tracts are sequence

boundaries (SB) transgressive surfaces (TS) and maximum flooding surfaces (MFS) (After Lang et al

2001)

74 Fluvial channel stacking patterns in relation to the amount and rate of available accommodation (after Lang

et al 2001 Allen et al 1996)

75 Sequence stratigraphic correlation of the Poolowanna Formation within the Moorari 3D seismic survey area

(after Nakanishi and Lang 2001a Nakanishi and Lang 2002)

76 Sequence stratigraphic correlation of the Poolowanna Formation within the Pondrinie 3D seismic surveyarea (after Nakanishi and Lang 2001b Nakanishi and Lang 2002)

77 Two-way time structure map of an intra-Poolowanna seismic horizon Moorari Field showing interpreted

sedimentary facies and gamma ray well log motifs (after Nakanishi and Lang 2001a Nakanishi and Lang

2002)

78 Two-way time structure map of an intra-Poolowanna seismic horizon Pondrinie Field showing interpreted

sedimentary facies and gamma ray well log motifs (after Nakanishi and Lang 2001b Nakanishi and Lang

2002)

79 Interpretation of sedimentary environments within of the upper Poolowanna Formation Moorari Field (after

Nakanishi and Lang 2001a Nakanishi and Lang 2002)

710 Schematic section showing potential Poolowanna Formation stratigraphic plays (a) Moorari Field (b)Pondrinie Field (After Nakanishi and Lang 2001a b Nakanishi and Lang 2002)

711 Sequence stratigraphic and chronostratigraphic summary of the Birkhead Formation (after Boult et al

1998 Lanzilli 1999)

712 Schematic 3D palaeogeography during the early phase of Birkhead deposition showing the influx of

cratonic-derived sediment from the south and volcanic-arc-derived sediment from the east (after Boult et

al 1998)

713 Sedimentary facies distribution and sequence stratigraphic correlation of the Birkhead Formation in the

Merrimelia and Meranji fieldsrsquo area (after Nakanishi et al 2003)

714 Schematic 3D palaeogeography during the deposition of the lowstand systems tract of the Birkhead

Formation in the GidgealpandashTindilpie area (after Boult et al 1998 Lanzilli 1999)

715 Palaeogeographic maps (a) Indicates palaeodrainage direction and source area below the sequence

boundary during Hutton time (b) With tilting of the Eromanga Basin and uplift of the volcanic arc

sediments of the lower Birkhead Formation were increasingly derived from the east with cessation of

supply from the southwestern cratonic source (After Boult et al 1997)

716 Generalised sequence through the Birkhead Formation and top Hutton Sandstone (after Lanzilli 1999)

717 Sedimentary facies interpretation of the middle-upper Birkhead Formation based on 3D seismic amplitude

variation and well logs within the Merrimelia Meranji and Pelican fieldsrsquo area (after Nakanishi et al 2003)

718 Regional WndashE cross-section from Gidgealpa 19 in South Australia to Maxwell 1 in Queensland showing

the relationship between the braided fluvial deposits of the Namur Sandstone and meandering fluvial-

lacustrine deposits of the Murta Formation (after Theologou 1995)





719 A typical well log of the Murta Formation from the Maxwell Field showing two major transgressivendash

regressive cycles (after Lang et al 2001)

720 NndashS cross-section Maxwell 1 to Mungoora 1 in Southwest Queensland showing an interpreted Murta

Formation sequence boundary and incised valley fill that represents the lowstand systems tract (after

Gorter 1994)

721 Generalised stratigraphic log of the Wyandra Sandstone Member Cadna-owie Formation showing key

surfaces and systems tracts The sequence boundary (SB) occurs at the base of the fluvial sandstones the

transgressive surface (TS) is marked by the onset of tidal structures and the two flooding surfaces (FS)

correlate to heterolithic bioturbated marine strata (After Lang et al 2001 Root 2001)



202770_108

(a)

(b)

(c)

(d)

Figure 71 Schematic representation of positive and negative fluvial accommodation (a b) Illustrate an

equilibrium profile that corresponds to base level with no net erosion or deposition of sediment

(c) A fall in equilibrium profile resulting in erosion of sediment (d) A rise in the equilibrium profile

resulting in aggradation of sediment (After Posamentier and Allen 1999)



Figure 72 Generalised stratigraphic column and sequences of the Cooper Eromanga and Lake Eyre basins(after Moussavi-Harami 1996)



Figure 73 Alluvial sequence stratigraphic model illustrating alluvial losystems tracts are sequence boundaries (SB) transgressive surface



202770_111

(a)

(c)

(e)

(b)

(d)

Figure 74 Fluvial channel stacking patterns in relation to the amount and rate of available accommodation

(after Lang et al 2001 Allen et al 1996)



-50 m

50 m

0 m

Figure 75 Sequence stratigraphic correlation of the Poolowanna Formation Moorari 3D seismi



-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N

Figure 76 Sequence stratigraphic correlation of the Poolowanna Formation Pon



202770_114

Figure 77 Two-way time structure map of an intra-Poolowanna seismic horizon Moorari Field showing interpreted sedimentary facies and gamma ray well log motifs (afterNakanishi and Lang 2001a Nakanishi and Lang 2002)



Figure 78 Two-way time structure map of an intra-Poolowanna seismic horizon Pondrinie Field showing interpreted sedimenta(after Nakanishi and Lang 2001b Nakanishiand Lang 2002)



202770_116

Figure 79 Interpretation of sedimentary environments within the upper Poolowanna Formation Moorari Field (after Nakanishi and Lang 2001a Nakanishi 2002)



Figure 710 Schematic section showing potential Poolowanna Formation stratigraphic plays (a) Moorari Field (b) Pondrinie Field (After Nakanishi and Lang 2001ab Nakanishi and Lang 2002)



Chronostratigraphic Section

Figure 711 Sequence stratigraphic and chronostratigraphic summary of the Birkhead Formation



Birkhead FormationUnit II (reworked Hutton)

Pre-Jurassic

Craton-derivedquartz arenites

Low energymeanderingfluvial to deltafill facies

R i f t i n g o f An t a r c t i c a

High energyaeolian braidedfluvial facies

Base BirkheaFormation Qu

N e e

b i n e

R i d g e

P T

N

T

Openlacustrinefacies

G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an

Figure 712 Schematic 3D palaeogeography during the early phase of Birkhead deposition showing

derived sediment from the east (after Boult et al 1998)



-50 m

50 m

0 m

100 m

MERANJI-7 PELICAN-1MERANJI-4 PELICAN

Figure 713 Sedimentary facies distribution and sequence stratigraphic correlation of



202770_119

Figure 714 Schematic 3D palaeogeography during the deposition of the lowstand systems tract of the Birkhea(after Boult et al 1998 Lanzilli 1999)



140deg

Early Birkheadtime

BraidedHutton

Low energyand reworked

BirkheadHutton

Labile sandstonewedge (mostlylow energy inEromanga Basin)

J

20deg

30deg

M

B

Restricted outletto lsquoLake Birkheadrsquo

B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150

= maximum influenceof labile sediment

Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM

= Bodalla South= Gidgealpa= Jackson= Moorari



202770_121

Figure 716 Generalised sequence through the Birkhead Formation and top Hutton Sandstone

(after Lanzilli 1999)



202770_122

Figure 717 Sedimentary facies interpretation of the middlendashupper Birkhead Formation based on 3D seismic amplitude variation and well logs Merrimelia Meranji and Pelican fields area

(after Nakanishi et al 2003)



Wantanna 1

Gidgealpa 19 Challum

Arrabury 1

Pondrinnie 1Bookaburdle 10

Tirrawarra 10Fly Lake 4

Marine

Distal LacustrineProximal Lacustrine

Lacustrinefluvialtransition

Braided fluvial

Fluvial incision

Flooding surfaceMaximum Flooding surface

Formation boundary

Figure 718 Regional WndashE cross-section from Gidgealpa 19 (South Australia) to Maxwell 1 (QueensSandstone and meandering fluvialndashlacustrine deposits of the Murta Formation (after Theologou 19



202770_124

Figure 719 Typical well log of the Murta Formation from the Maxwell Field

showing two major transgressivendashregressive cycles (after Lang et al 2001)



Figure 720 NndashS cross-section from Maxwell 1 to Mungoora 1 (South West Queensland) showing an interpreted Murta Formaboundary and incised valley fill that represents the lowstand systems tract (after Gorter 1994)



202770_126





INTRODUCTION

Sequence stratigraphy provides a basis for the chronostratigraphic correlation of sediments and a valuable

exploration and reservoir development tool for the petroleum industry A sequence stratigraphic approach to

correlation on both a regional and field-scale coupled with an understanding of depositional environments and the

roles of accommodation space and sediment supply can aid in the reconstruction of palaeogeography and

prediction of temporal and spatial relationships between source reservoir and seal facies While the concepts of

sequence stratigraphy have been readily applied to passive margin and foreland basin settings there has been

significantly less focus on their application to intra-cratonic and fluvial-dominated basins (Posamentier and Allen

1999 Lang et al 2001)

In the Eromanga Basin sequence stratigraphy has been applied sporadically on a field and regional scale within a

lithostratigraphic framework to better understand the relationships between and distribution of key depositional

facies The relatively dense well coverage throughout the Cooper region of the Eromanga Basin in both South

Australia and Queensland forms the basis for the correlation of geophysical well logs and delineation of systems

tracts on a regional scale (eg Lanzilli 1999) The availability of high-resolution 3D seismic over producing

Eromanga Basin petroleum fields and the resultant ability to visualise facies elements through such techniques as

seismic amplitude mapping have enabled the application of sequence stratigraphic concepts on a field scale toenhance reservoir development and delineate potential stratigraphic traps (eg Nakanishi and Lang 2002)

While there has been widespread recognition of major sequence boundaries and flooding surfaces within various

studies a complete detailed sequence stratigraphic study of the entire Eromanga Basin sequences has yet to be

undertaken One of the principal reasons for the limited application of sequence stratigraphy is that exploration has

been relatively successful without the need for detailed studies of sediment distribution (Lanzilli 1999) A sequence

stratigraphic approach to the correlation of Eromanga Basin sediments together with the reconstruction and

understanding of palaeo-depositional environments has potential to provide new exploration and development

opportunities within the basin

KEY CONCEPTSThis chapter aims to review recent studies that have incorporated the use of sequence stratigraphy to better

understand and predict the spatial distribution of sedimentary facies within the Eromanga Basin sequence For a

comprehensive account of sequence stratigraphic concepts and their application to fluviolacustrine depositional

systems the reader is directed to these relevant publications Posamentier and Allen 1999 Lang et al 2001

Nakanishi and Lang 2002 There is however a need within this discussion to provide a brief review of some of the

basic concepts and ideas pertaining to the application of sequence stratigraphy within a dominantly fluviolacustrine

depositional environment

Accommodation space and sediment supply

To understand the distribution of sedimentary facies within any basin it is critical to understand the interaction

between accommodation space and sediment supply Accommodation space in fluviolacustrine settings is the

space between the ground surface (subaerial or subaqueous) and the fluvial equilibrium profile (base level) to

which sediments will potentially fill or be eroded in the case of negative accommodation (Fig 71 Posamentier and

Allen 1999) In the Eromanga Basin where marine influence and hence eustatic fluctuation was restricted to the

Early Cretaceous the dominant controls on accommodation space were largely provided by tectonically driven

periods of subsidence and uplift together A generally low accommodation space persisted in the Eromanga Basin

The rate type and amount of sediment entering the basin were influenced by a combination of factors including

provenance climate and topographic relief

Sequences and systems t racts A lsquotypicalrsquo fluviolacustrine sequence comprises a relatively conformable succession of genetically related strata

bounded by regionally significant unconformities (Posamentier and Allen 1999 Lang et al 2001) In this context

























































2001)



























Stratigraphic traps

































HUTTON SANDSTONE
























BIRKHEAD FORMATION













1999 Fig 714)



































Stratigraphic traps
















































NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126

























































2001)



























Stratigraphic traps

































HUTTON SANDSTONE
























BIRKHEAD FORMATION













1999 Fig 714)



































Stratigraphic traps
















































NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126





























HUTTON SANDSTONE
























BIRKHEAD FORMATION













1999 Fig 714)



































Stratigraphic traps
















































NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126







BIRKHEAD FORMATION













1999 Fig 714)



































Stratigraphic traps
















































NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126







Stratigraphic traps
















































NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126







NAMUR SANDSTONE














MURTA FORMATION

























































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126

































FIGURES









2001)








2002)



2002)





1998 Lanzilli 1999)



al 1998)























Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126









Gorter 1994)







202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_108

(a)

(b)

(c)

(d)













202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126









202770_111

(a)

(c)

(e)

(b)

(d)





-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



-50 m

50 m

0 m




-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



-50 m

50 m

0 m

100 m

NAP-1 NAP-2 YAL-1 N




202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_114







202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126






202770_116












Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126











Pre-Jurassic






N e e

b i n e

R i d g e

P T

N

T


G M I R

i d g e

M

J

J

B

Q

L D

S A

Er om

anga

Basin

South

Austr

alian

High

lands

Hutt o

n S an





-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



-50 m

50 m

0 m

100 m





202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_119




140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



140deg

Early Birkheadtime

BraidedHutton


BirkheadHutton


J

20deg

30deg

M

B


B i r d s

v i l l e T

R

Craton-derived

sediments

Volcanic-arc-

derived Sediments

G

lake

Sydney

Braided Hutton

Cratonic sourcearea

V o l c a n

i c A r c

140deg 150deg

20deg

30deg

40deg

500 km

Presentshoreline

Mesozoicbasin

202770 082

(a)

(b) 150


Cratonic source

area

l a t e

H

t t u

o n

e x i t

ear ly Hu t t o n

e x i t

Hutton time

BGJM




202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_121





202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_122





Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



Wantanna 1


Arrabury 1



Marine



Braided fluvial

Fluvial incision


Formation boundary




202770_124








202770_126



202770_124








202770_126






202770_126

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