DYNAMIC PALEO-REDOX SIGNAL PRESERVED IN THE KELLWASSER INTERVAL IN NEW YORK STATE

The Late Devonian Kellwasser Event is a globally recognized extinction event that is widely thought to be associated with marine anoxia, in part due to the pervasiveness of black shale preservation. The Kellwasser equivalent has been recognized in Frasnian aged strata that are easily accessed in upstate New York and provide an opportunity to test the extent and persistence of anoxia and/or euxinia through this interval. At six localities in western New York nearly 100 samples were collected from intervals through the Kellwasser event (Frasnian-Famennian boundary). Relative oxygen levels are recognized in these samples using ichnological methods, specifically burrow size and relative amount of bioturbation, trace metal concentrations and pyrite framboid data. Within these units, rapid variations in ichnofabric index values, as a proxy for bottom water oxygen levels, and fluctuating but moderately enriched values of redox sensitive trace metals such as Mo, U, and V, support a complex oxygen history. The pyrite framboid data are consistent with the other proxies. More specifically the combined approach used in this study argue against persistent anoxia or euxinia in these intervals. The dynamic paleo-redox conditions interpreted through the Kellwasser event help to clarify our view of extinction mechanisms through the end Devonian mass extinction event.