GSA Connects 2021 in Portland, Oregon

Paper No. 75-5
Presentation Time: 9:15 AM


KIMMIG, Julien, Pennsylvania State University, University Park, PA 16803, WHITAKER, Anna F., Department of Geological Sciences, University of Missouri, 2428 Pimlico Ct, Columbia, MO 65201-7385, EGENHOFF, Sven, Department of Geosciences, Colorado State University, 322 Natural Resources Building, Fort Collins, CO 80523-1482, SCHIFFBAUER, James D., Geological Sciences, University of Missouri, 101 Geological Sciences Bldg, Columbia, MO 65211, LAVINE, Rhiannon, Biodiversity Institute, University of Kansas, 1345 Jayhawk Blvd, Lawrence, KS 66045-7593, KRUMENACKER, L.J., Department of Geological Sciences and IMNH, Idaho State University, Pocatello, ID 83209 and KIMMIG, Sara R., Laboratory for Isotopes and Metals in the Environment (LIME), Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802

The middle Cambrian (Miaolingian Series, Wuliuan Stage) Spence Shale Member of the Langston Formation in northeastern Utah and southeastern Idaho is a relatively well-known Burgess Shale-type deposit. In addition to its abundant biomineralized fauna, the soft-bodied biota preserved in the Spence is diverse, including various arthropods, priapulids, deuterostomes, and lobopodians. While the Spence Shale is often regarded as a single deposit in the literature, it is imperative to recognize that there are notable differences between the separate outcrops. Not only are there variations in sedimentology, modes of preservation of the soft-bodied fossils, and fossil diversity at the outcrop scale, but these elements can also vary within a few meters of the same exposure. Part of this variation is attributed to changing depositional environments along the continental shelf, but modern weathering and historical collections bias may also play significant roles. However, understanding the correlative nature of these proxies is in its infancy. Here we present new data from sedimentological, petrographic, paleontological, geochemical, and SEM-EDS analyses which showcase the importance of a multiproxy approach to the understanding of this convoluted deposit. Our aim is to provide improved clarity onto the paleoecological and taphonomic questions that have plagued the Spence Shale for decades.