Transcript Fossil Assemblage Characteristics

An Exercise at Recognizing Good vs. Poor Spatial and
Temporal Fidelity
Assemblage Types
Biocoenosis: All members of the
community are represented.
 Thanatocoenosis: All fossils present
were members of the community, but
some members are missing.
 Taphocoenosis: Some fossils present
were not members of the community –
time averaged (poor temporal fidelity) or
transported (poor spatial fidelity)
assemblage
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How Do You Distinguish Among
Assemblage Types?
Each should have some predictable set
of biostratinomic features.
 Each should have different bioclast
fabrics.
 Each should have different
sedimentologic characteristics.
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Problem: Case of Unusual
Preservation
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Find a strangely preserved fossil
assemblage in Hamilton Group rocks
(Middle Devonian, 350 Ma) from western
New York State.
Found in thin limestone beds.
A large interior seaway sat on the interior of
North America at this time.
Your task: Determine which type of
assemblage is represented.
The following slides and associated notes
will guide you through the problem.
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A
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A