Cambrian Ichnostratigraphy of the Eastern Basin and Range and Western Rocky Mountains

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The proposed research focuses on the utility of ichnofossils (biogenic sedimentary structures) for biostratigraphy and paleoenvironmental studies in the eastern Great Basin and western Rocky Mountains. Four aspects of Lower Cambrian trace fossils will be studied: ichnotaxonomy (systematic classification); mode of production (tunnels, open furrow, etc.); ichnostratigraphy; paleoecologic and paleogeographic implications. Preliminary work has revealed a great diversity and abundance of ichnofossils in this area. In addition, diverse fossil assemblages of potential trace-makers also are present. A revision of the taxonomic classification of arthropod trace fossils will be undertaken, and a set of taxonomic criteria that can be applied consistently across the group will be formulated. Consideration will include patterns of morphology, mechanics of construction, the type of structure (endogenic or epigenic), and inferred trace-makers. The stratigraphic distribution of trace fossils within the Lower Cambrian of Utah and adjoining areas will be documented, and the global significance of Cambro-Ordovician stratigraphic models using ichnospecies of Cruziana and Rusophycus will be assessed. The mode of production of Cruziana and Rusophycus will be investigated by the examination of samples and the reproduction of traces in sediment flume and aquarium experiments, using modern trace-makers (e.g., insects and crustaceans). Characterization of relationships between ichnofacies and lithofacies (or lithotopes) will be made to document benthic community relationships in the early Paleozoic. Trace fossils also can furnish detailed information about important environmental factors, such as substrate consistency, salinity, and sediment anoxia. Patterns in the distribution of these factors allow local paleogeography to be inferred, which will allow existing regional paleogeographic models to be defined more clearly than they are at present.//