Paper Number: 1678
The Last of the Ediacara Biota: The Precambrian-Cambrian Boundary at Mt. Dunfee, Nevada, USA
Smith, E.F.1, Nelson, L.L.2, Strange, M.A. 3, Eyster, A.E.2, Rowland, S.M. 3, Schrag, D.P. 2, and Macdonald, F.A.2
1Department of Paleobiology, Smithsonian Institution, PO Box 37012, MRC 121, SmithEF@si.edu
2Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138
3Department of Geoscience, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4010
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Here we report new stratigraphic, paleontological, and geochemical data from exposures at Mt. Dunfee, Nevada, USA, which preserve the last appearance datum (LAD) of Ediacaran biota, the LAD of Cloudina, the first appearance datum (FAD) of vertical burrows preserved as the trace fossil Treptichnus pedum, and a large negative δ13C excursion in carbonate strata. The Ediacaran body fossil assemblages from the Deep Spring Formation include exceptionally preserved specimens of Conotubus, Gaojiashania, other vermiform body fossils, and possible Wutubus annularis. This is the first definitive report of Conotubus and Gaojiashania outside of South China, extending the known stratigraphic and biographic ranges of these taxa to a global scale. The younger of the two fossil assemblages occurs within the basal Cambrian negative δ13C excursion, establishing it as the youngest Ediacaran fossil assemblage discovered to date. We further discuss how these sections correlate with better-known successions exposed in Death Valley and globally. The integrated dataset from Mt. Dunfee demonstrate that a large perturbation to the carbon cycle coincided with major biological turnover and the radiation of bilaterian metazoan ecosystems across the Ediacaran-Cambrian transition.