SEDIMENTARY%20ARCHIVES

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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Carbonates
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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Carbonates Origin of carbonate sediments Much
lime mud forms from the disintegration of
calcareous algae (such as Halimeda and
Penicillus). When the calcareous algae die,
their skeletons break down and disintegrate
producing aragonite needle muds. These lime muds
lithify to form fine-grained limestone.
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SEDIMENTARY ARCHIVES
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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Carbonates Fossiliferous limestone Biomicrite B
iosparite
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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Carbonates Oolitic limestone Oomicrite Oosparit
e
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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Carbonates Dolostone Composed of dolomite
(CaMg(CO3)2) The Dolomite Problem Dolomite
is believed to form when magnesium that has been
concentrated in sea water replaces calcium
carbonate in a previously deposited limestone.
Today, dolomite only forms in a few areas of
the world where intense evaporation of
seawater concentrates the magnesium. Extensive
areas of carbonate rocks of Precambrian,
Paleozoic, and Mesozoic age have been altered
to dolomite. Dolomitization may be related to
times of high sea level worldwide, under
favorable climatic conditions.
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SEDIMENTARY ARCHIVES
Classification of Sedimentary Rocks
Clays, Mudrocks and Shales Mudrocks are a very
fine-grained Composed of clay and silt-sized
particles If the mudrock is fissile it is a
-shale Typically form in low energy environments
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SEDIMENTARY ARCHIVES
Sea Level Changes
Eustatic Sea Level Change Global change in sea
level position Caused by Glacial advance and
retreat Change in spreading rates Effect
lowland areas
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SEDIMENTARY ARCHIVES
Sea Level Changes
Sequence Stratigraphy Epeiric seas Seas covered
continents Produced packages called
sequences Led to sequence stratigraphy
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SEDIMENTARY ARCHIVES
Sea Level Changes Sequence Stratigraphy
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SEDIMENTARY ARCHIVES
Sea Level Changes
Sequence Stratigraphy A group of relatively
conformable strata that represents a cycle of
deposition and is bounded by unconformities or
correlative conformities. Sequences are the
fundamental unit of interpretation in sequence
stratigraphy. Sequences comprise systems tracts.
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SEDIMENTARY ARCHIVES
Sea Level Changes
Vail Curve
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SEDIMENTARY ARCHIVES
Sequence Stratigraphy
Sea Level Changes
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SEDIMENTARY ARCHIVES
Sea Level Changes
Sequence Stratigraphy
http//strata.geol.sc.edu/clastic-movie.html
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THE FOSSIL RECORD
Paleontology
Attempts to understand all aspects of the
succession of plants and animals over
time. Based on study of fossils
Archaeopteryx
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THE FOSSIL RECORD
Paleontology
Fossil Preservation Cover this aspect in
laboratory Fossilization fortuitous Chances
enhanced by Hard parts Rapid
burial Environments Oceans, lakes and streams
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THE FOSSIL RECORD
Taphonomy What happens to an organism from time
of death to preservation as a fossil Soft parts
usually lost