GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 184-12
Presentation Time: 11:00 AM


MUSCENTE, A. Drew1, LAFLAMME, Marc2, SCHIFFBAUER, James D.3, BROCE, Jesse S.4, O'DONNELL, Kenneth H.5, BOAG, Thomas H.6, MEYER, Michael7, HAWKINS, Andrew D.8, HUNTLEY, John Warren3 and XIAO, Shuhai8, (1)Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, (2)Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada, (3)Geological Sciences, University of Missouri, 101 Geological Sciences Building, Columbia, MO 65211, (4)Geological Sciences, University of Missouri, 101 Geology Building, Columbia, MO 65211, (5)Germantown, MD 20876, (6)Department of Geological Sciences, Stanford University, 450 Serra Mall Bldg. 320, Stanford, CA 94305, (7)Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC, DC 20015, (8)Department of Geosciences, Virginia Tech, Blacksburg, VA 24061,

Exceptionally preserved fossils of non-biomineralized tissues provide key insights into anatomies and communities of ancient organisms. Assemblages of such fossils are not evenly distributed through geologic time or space, suggesting exceptional fossil preservation is controlled by factors operating on global scales. Establishing the influence of global factors, however, requires documentation of temporal and spatial trends in the occurrences of such assemblages through the geologic history of complex life. To this end, we compiled and analyzed a dataset of 694 globally distributed fossil assemblages from ~610 to 3 Ma (Mega anna). Our analyses show that clusters of exceptional fossil assemblages decline in number and shift from open marine to restricted (transitional and non-marine) depositional settings through the Ediacaran-Silurian (635–420 Ma) interval in concert with increasing oxygenation of the ocean-atmosphere system and development of bioturbation. Thereafter, clusters of exceptional fossil assemblages generally rise in number through the Devonian-Neogene (420–3 Ma) interval with increasing non-marine sedimentary rock quantity and improving geologic sampling. Secular environmental transitions and rock record biases, thus, overprint the distribution of exceptionally preserved fossil assemblages in geologic time and space. Overall, our study affirms the importance of low oxygen and bioturbation levels in the conservation of non-biomineralized tissues, demonstrates the role of rock record bias in the exceptional fossil record, and provides fundamental bases for understanding occurrences of exceptionally preserved fossils through time and space.