graphic correlation: overview -...
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Stratigraphy
The part of geology that deals with the formation, composition, sequence, and correlation of rocks, especially stratified rocks
Limestone
Sandstone
Shale
Limestone
Sandstone
Shale
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Stratigraphy
The part of geology that deals with the formation, composition, sequence, and correlation of rocks, especially stratified rocks
Limestone
Sandstone
Shale
• underpins all of geology
Limestone
Sandstone
Shale
1
Stratigraphy
The part of geology that deals with the formation, composition, sequence, and correlation of rocks, especially stratified rocks
Limestone
Sandstone
Shale
• underpins all of geology• deals especially with time element
Limestone
Sandstone
Shale
1
Stratigraphy
The part of geology that deals with the formation, composition, sequence, and correlation of rocks, especially stratified rocks
Limestone
Sandstone
Shale
• underpins all of geology• deals especially with time element
• supplies ‘4th dimension’ for localizing geological material
Limestone
Sandstone
Shale
1
Stratigraphy
The part of geology that deals with the formation, composition, sequence, and correlation of rocks, especially stratified rocks
Limestone
Sandstone
Shale
• underpins all of geology• deals especially with time element
• supplies ‘4th dimension’ for localizing geological material
• essential for studies on evolution and environmental change through time
Limestone
Sandstone
Shale
1
• Lithostratigraphy: establishing the geometrical shape and spatial relationship of rock bodies
• Establishing a formal (relative) time framework - chronostratigraphy
• Determining numerical ages for units, i.e. geochronology
Main activities
• Correlating successions with one another and with the chronostatigraphical standard: often by using biostratigraphy
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LithostratigraphyThe part of stratigraphy dealing with the lithology of strata and with their organization into units based on lithological character.
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LithostratigraphyThe part of stratigraphy dealing with the lithology of strata and with their organization into units based on lithological character.
BiostratigraphyThe part of stratigraphy dealing with the fossil content of strata and with their organization into units based on the distribution of fossils.
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ChronostratigraphyThe part of stratigraphy dealing with the recognition of named units corresponding to intervals of geological time to serve as a reference system for recording events in geological history.
LithostratigraphyThe part of stratigraphy dealing with the lithology of strata and with their organization into units based on lithological character.
BiostratigraphyThe part of stratigraphy dealing with the fossil content of strata and with their organization into units based on the distribution of fossils.
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Salvador (1994)
Formation- Member-Beds: lithostratigraphic units
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Salvador (1994)
Different biostratigraphicalunits: biozones
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Salvador (1994)
Geophysical units
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Salvador (1994)
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Lithostratigraphy
The part of stratigraphy dealing with the organization of rocks into units based on their lithological character.
Formation C
Formation B
Formation A
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Strata are continuous and of the same thickness over long distances
A
B
C
D
E
F
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Diachrony - age of lithological units varies laterally
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2
3
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Biostratigraphy
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Biostratigraphy
• The part of stratigraphy dealing with the distribution of fossils in the stratigraphical record and the organization of strata into units based on the basis of their contained fossils
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Biostratigraphy
• The part of stratigraphy dealing with the distribution of fossils in the stratigraphical record and the organization of strata into units based on the basis of their contained fossils
• Biostratigraphical units are termed biozones, e.g. Globigerina brevis Biozone (note capital ‘B’ in Biozone)
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Biostratigraphy
• The part of stratigraphy dealing with the distribution of fossils in the stratigraphical record and the organization of strata into units based on the basis of their contained fossils
• Biostratigraphical units are termed biozones, e.g. Globigerina brevis Biozone (note capital ‘B’ in Biozone)
• Hierarchy of Superbiozones (Superzones), Biozones (Zones), Subbiozones (Subzones)
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species biozone
Correlation of strata by their contained fossils independent of lithology: Biostratigraphy
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species biozone
Correlation of strata by their contained fossils independent of lithology: Biostratigraphy
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SBZ 3
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SBZ 3
P4a, b
P4c
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Biozones may be diachronous
Envelope of species distribution
A B C D E
Space
Tim
e
later first appearance
later disappearance
Geographic range
time
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Index fossils
• Widely distributed
• Abundant in the fossil record
• Facies independent
• Evolve rapidly so that biozones are of short duration
• Easily identifiable
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Index fossils
• Widely distributed
• Abundant in the fossil record
• Facies independent
• Evolve rapidly so that biozones are of short duration
• Easily identifiable
Deep vs shallow marine
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Chronostratigraphy
The part of stratigraphy dealing with the relative time relationships and ages of rocks.
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Chronostratigraphy
The part of stratigraphy dealing with the relative time relationships and ages of rocks.
Chronostratigraphical units are bodies of rock that were formed during a specified interval of geological time.
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Chronostratigraphy
The part of stratigraphy dealing with the relative time relationships and ages of rocks.
Chronostratigraphical units are bodies of rock that were formed during a specified interval of geological time.
The intervals of time during which chronostratigraphical units were formed are called geochronological units.
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(Salvador 1994, pp. 10-11)
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sand = chronostratigraphical unit
(Salvador 1994, pp. 10-11)
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sand = chronostratigraphical unit
time taken for sand to pass through hourglass = geochronological unit
(Salvador 1994, pp. 10-11)
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Chronostratigraphyand Geochronology
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Chronostratigraphyand Geochronology
Stage (and Age)
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Chronostratigraphyand Geochronology
Stage (and Age)
• basic working unit of chronostratigraphy
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Chronostratigraphyand Geochronology
Stage (and Age)
• basic working unit of chronostratigraphy• normally the lowest ranking unit that can be recognized on a global scale
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Chronostratigraphyand Geochronology
Stage (and Age)
• basic working unit of chronostratigraphy• normally the lowest ranking unit that can be recognized on a global scale• variable in time span, but most stages are 2-10 million years long
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Chronostratigraphyand Geochronology
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Chronostratigraphyand Geochronology
Chronozones
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Chronostratigraphyand Geochronology
Chronozones
• chronostratigraphical units
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Chronostratigraphyand Geochronology
Chronozones
• chronostratigraphical units
• corresponding geochronological unit is the chron
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Chronostratigraphyand Geochronology
Chronozones
• chronostratigraphical units
• corresponding geochronological unit is the chron
• comprise the body of rocks formed anywhere during the time span of some designated stratigraphical unit (e.g. a biozone) or geological feature (e.g. Deccan Traps volcanism)
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Chronostratigraphyand Geochronology
Chronozones
• chronostratigraphical units
• corresponding geochronological unit is the chron
• comprise the body of rocks formed anywhere during the time span of some designated stratigraphical unit (e.g. a biozone) or geological feature (e.g. Deccan Traps volcanism)
• named according to the stratigraphical unit on which it is based, e.g. Exus albus Chronozone is based on Exus albus Range Zone
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What is relevant to our work?
1) A fossil out of context is very difficult to place in a stratigraphical framework
2) Southeast Asia is tectonically highly active, often resulting in restricted lateralextension of facies
3) Current climate is favours rainforest development
4) Combined this makes lithostraitgraphical correlation difficult, and we need to get as much as possible out of those outcrops we have available
5) Most stratigraphical units that we are using are defined outside our regionof interest.
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Ta
Tb
Tc
Td
Te 1-4
Tf1-2
Paleocene- Middle Eocene
Late Eocene
Early Oligocene
Late Oligocene
Aquitanian
Burdigalian- Serravallian
Te5
Tf3
1) Improve correlation with less local stratigraphic schemes
2) In some way formalize this biostratigraphical zonation so that
a. regional differences can be discussedb. Our findings can be placed in a global
context
Southeast Asian Letter classification
BiozoneEpoch/Stage
Originally formulateed as chronostratigraphical units, but later often interpreted as Larger Benthic Foraminifera Biozones
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• Stratigraphic schemes can not be horizontally relocated to other regions
Regional stratigraphic schemes
• Stratigraphic ranges of species differ
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Stratigraphy
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