Paper No. 10-13
Presentation Time: 11:20 AM
MULTI-PROXY ANALYSIS OF THE LOWER KELLWASSER EVENT IN THE APPALACHIAN BASIN
Mass extinctions are often associated with extreme changes in environmental conditions, which vary widely among these events. Studies of the Late Devonian (Frasnian-Famennian) extinction event have implicated numerous potential kill mechanisms including widespread oceanic anoxia and climate change. The Frasnian-Famennian extinction intervals (Lower and Upper Kellwasser events; LKW and UKW) are often associated with deposition of organic-rich sediments, evidence of anoxia or dysoxia, and nitrogen cycle perturbations; specifically shifting δ15Norg values antithetic to δ13Corg excursions. In the deeper end of the Appalachian Basin, the Kellwasser-equivalent beds were deposited under alternating dysoxic/anoxic conditions. However, preliminary δ15Norg data from the shallower portions of the basin were consistent with intermittent periods of anoxia, while major and trace element concentrations indicate consistent oxygenation of the water column through the Kellwassers. Here, we present new data detailing δ15Norg, δ13Corg, trace elements, and sedimentology from sections throughout the shallow portions of the Appalachian Basin in New York and Pennsylvania. Analysis of these data seem to indicate that, rather than being linked to a universal drop in oxygen levels, δ15Norg values in the shallow portions of the Appalachian Basin are potentially reflective of the sources and proximity of terrestrial input into the basin.