RUI -- COLLABORATIVE RESEARCH: Integrated Stratigraphic Study of Cambrian-Ordovician Inner Shelf Facies of the Western United States

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9972936MyrowPeriodic extinctions of Laurentian platform invertebrates in the Late Cambrian have been attributed to changes in sea level and other paleoceanographic events. Such hypotheses are testable but require a more precise and complete biostratigraphic, sedimentologic, andchemostratigraphic data set than is currently available. A thorough sequence-stratigraphic analysis of Upper Cambrian and Lower Ordovician inner shelf successions in the western United States will provide such a data set. Sub-meter scale sampling for trilobites, conodonts, and Carbon isotopes will provide a highly-refined chronostratigraphic framework in which to test the posited coincidence of faunal change with times of sea level rise or fall and/or oceanic overturn. Additionally, comparison of relative sea level curves constructed for the western (Wyoming and Montana) and eastern (southwestern US) paleoshelves will test the validity of numerous eustatic events that have been proposed for the Late Cambrian and earliest Ordovician.