GSA Connects 2021 in Portland, Oregon

Paper No. 10-10
Presentation Time: 10:35 AM


STOLFUS, Brittany, University of IowaDepartment of Earth and Environmental, 115 Trowbridge Hall, Iowa City, IA 52242-1319, ALLMAN, Lindsi, 3533 Cypress Hawk Ln, Tallahassee, FL 32310-6356, CRAMER, Bradley, Department of Earth and Environmental Sciences, University of Iowa, 115 Trowbridge Hall, Iowa City, IA 52242, YOUNG, Seth, Earth Ocean and Atmospheric Science, Florida State University, 3533 Cypress Hawk Lane, Tallahassee, FL 32310, CALNER, Mikael, Department of Geology, Lund University, Sölvegatan 12, Lund, SE-223 62, Sweden, HARTKE, Emma, Department of Geosciences, Penn State University, University Park, PA 16802, OBORNY, Stephan, University of KansasKansas Geological Survey, 1930 Constant Ave, Lawrence, KS 66047-3726 and BANCROFT, Alyssa M., Iowa Geological Survey, University of Iowa, 340 Trowbridge Hall, Iowa City, IA 52242

New sulfur isotope data, including δ34Spy (pyrite) and δ34SCAS (carbonate-associated sulfate), provide additional evidence for the expansion of reducing oceanic conditions during the early Silurian Ireviken Biogeochemical Event (IBE). This event consists of major perturbations to biogeochemical cycles including major positive carbon and sulfur isotope excursions and increased biotic turnover/extinction. In addition, recent studies have hypothesized that this event coincides with an expansion of reducing marine conditions which allowed for organic carbon burial rates to increase globally leading to the Ireviken positive Carbon Isotope Excursion (ICIE).

Recent work in the Altajme core from Gotland, Sweden provides the highest resolution carbon isotopic record of the ICIE in a stratigraphic section and provides an expanded stratigraphic section ideal for studying biogeochemical events. Within the Altajme core, the δ34Spy values and pyrite concentrations increase at the onset of the ICIE indicating an increase in pyrite burial rates in the marine sediments locally. This dataset along with other previously published δ34SCAS datasets from the Baltic and distant basins suggests an expansion of reducing conditions led to an increase in organic carbon burial and the ICIE.