Paper No. 256-3
Presentation Time: 9:00 AM-6:30 PM
INVESTIGATING A UNIQUE OPEN OCEAN GEOCHEMICAL RECORD OF THE END TRIASSIC MASS EXTINCTION FROM PANTHALASSA
MARROQUÍN, Selva M., Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall, Blacksburg, VA 24060, GILL, Benjamin C., Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall, Blacksburg, VA 24061, THEM, Theodore R., Department of Earth, Ocean and Atmospheric Science, Florida State University, National High Magnetic Field Laboratory, Tallahassee, FL 32306, TRABUCHO-ALEXANDRE, João P., Institute of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands, ABERHAN, Martin, Museum für Naturkunde, Invalidenstr. 43, Berlin, 10115, Germany, OWENS, Jeremy D., Department of Earth, Ocean, and Atmospheric Sciences, Florida State University, National High Magnetic Field Laboratory, Tallahassee, FL 32306, GRÖCKE, Darren R., Department of Earth Sciences, University of Durham, Science Labs, Durham, DH1 3LE, United Kingdom and CARUTHERS, Andrew, Michigan Geological Survey, Western Michigan University, 1903 W. Michigan Ave, Kalamazoo, MI 49008-5241, selva@vt.edu
The end-Triassic mass extinction (~201 Ma) was a time of intense disturbance for marine communities. This event is estimated to have produced as much as a loss of ~80%
of known marine species. The protracted interval of elevated extinction rates is also characterized by a major carbon cycle perturbation and potentially widespread oxygen deficiency within the oceans. While the causes of extinction and environmental feedbacks are still debated it is hypothesized to have been triggered by massive volcanism associated with the Central Atlantic Magmatic Province flood basalts. However, our understanding of the Latest Triassic-Earliest Jurassic interval is limited due to the lack of well-preserved stratigraphic successions outside of the Tethys Ocean (present day Europe), with most of the records from epicontinental and marginal marine settings. To expand our understanding of this critical interval, our study seeks to document biological and environmental changes elsewhere. Specifically, we document and reconstruct these changes in the equatorial Panthalassan Ocean.
We will present new data from a sedimentary succession preserved in the Wrangell Mountains of Alaska that spans the Late Triassic through Early Jurassic. The sedimentary succession represents a mixed carbonate-siliciclastic ramp that was deposited at tropical latitudes, adjacent to an island arc in the open Panthalassan Ocean. This succession affords a unique view of open marine conditions, and also holds the potential for excellent temporal control as it contains abundant ash layers throughout, as well as, key ammonite and bivalve fossil occurrences that provide biostratigraphic control. We will present a δ13Ccarb record from this site along with ammonite and bivalve occurrence data to reconstruct the record of environmental and biological change within the open Panthalassan Ocean, and relate these data to existing marine records of the end-Triassic extinction.
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