Mesozoic Return of Brachiopods: Brachiopod-Dominated Shell Beds in the Middle Triassic
Sarah E. Greene, David J. Bottjer, and John-Paul Zonneveld
University of Southern California, Department of Earth Sciences
Los Angeles, CA, USA
[email protected]
The benthic marine diversity and paleocommunity structure of the Early Triassic indicates that deleterious environmental conditions associated with the end-Permian mass extinction persisted for ~5 million years. It is known that benthic marine faunal diversity increased in the Middle Triassic, but it has yet to be established how these communities reorganized once environmental stress abated.
To further understanding of Middle Triassic benthic marine paleoecology, shell beds from the Ladinian Liard Formation, exposed at Williston Lake, British Columbia (Canada), were examined. The Liard Formation, a mixed siliciclastic-bioclastic succession, represents a shallow shelf setting with a prograding, storm-dominated, barrier island shoreline. Shell beds, in addition to providing information about biological diversity, are important indicators of ecological structure, particularly dominance. 58 shell beds were surveyed to establish thicknesses and fossil constituents. 33 shell beds were dominated by terebratulid brachiopods, 23 were encrinites (composed primarily of crinoid material), and 2 were brachiopod-encrinite composites. Average![Previous Hit](/images/arrow_left.gif)
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AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid