Paleobiology and Taphonomy of Lower Cambrian Burgess Shale-Type Deposits of Nevada and Greenland

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ABSTRACTPALEOBIOLOGY AND TAPHONOMY OF LOWER CAMBRIAN BURGESS SHALE-TYPE DEPOSITS OF NEVADA AND GREENLANDLoren E. BabcockEAR-0106883This study involves the paleobiology and taphonomy (postmortem history) of two Early Cambrian Burgess Shale-type biotas from western Nevada and North Greenland. The biotas, both from the Laurentian (North America-Greenland) paleocontinent, represent two of the oldest known assemblages of exceptionally preserved animals in the world. These assemblages overlap in part the time of the Cambrian adaptive radiation of multicellular animals. They provide important "windows" into the evolutionary history of the Early Cambrian, and they should provide information about the conditions under which exceptional preservation occurred. The primary purposes of this work are: 1, to collect and document the biota of the new Nevada site and continue documentation of the biota of the Greenland site; 2, to document and interpret information about the taphonomy of the Nevada and Greenland sites; 3, to describe and interpret trace fossils associated with the body fossils; 4, to describe and interpret the stratigraphic and sedimentologic context of exceptional preservation in the Nevada and Greenland sites; and 5, to determine the biogeographic affinities of nonmineralized organisms present in the Early Cambrian biotas. Completion of this work will provide important information about biologic diversity on the North America-Greenland paleocontinent prior to the terminal Early Cambrian extinction. This, in turn, is expected to provide a strong basis for biogeographic comparison with Early Cambrian biotas of Gondwanan areas, and a basis for comparison with biotas from the Middle Cambrian of Laurentia.