Paper No. 68-4
Presentation Time: 2:25 PM
THREE EXTINCTION EVENTS (CAPITANIAN CRISIS, LATEST PERMIAN EXTINCTION, AND THE SMITHIAN/SPATHIAN EXTINCTION) MARKED BY MERCURY ANOMALIES IN NW PANGEA
Three major extinction events (Capitanian Crisis, Latest Permian Extinction, and the Smithian/Spathian Extinction) are recorded in Permian through Early Triassic strata in the Festningen section of Spitsbergen. We examined the Hg record through these extinction events, representing an ~ 12 Ma period. Results show relatively constant background values of 0.005 to 0.010 mg/g Hg in the sediments. However, there are notable spikes in Hg concentration that are over an order of magnitude above background associated with the three extinction events. We also examined the Hg/TOC ratio to determine if these represent simple changes in organic burial and associated drawdown of Hg, or true increase in Hg loading to the environment. Hg/TOC data shows similar large spikes at the three extinction events, suggesting that the extinction events have associated increase in Hg deposition. We argue that these Hg loading events are associated with enhanced Hg emissions from large igneous province (LIP) events that are synchronous with the extinctions. Volcanoes are the largest natural source of Hg to the environment, and as such enhanced activity during LIP events should have associated increase in Hg loading to the environment. The Hg anomalies are consistent across the NW margin of Pangea, indicating widespread mercury loading occurred. While our results show that Hg records provide utility as a chemostratigraphic marker of LIP events, the Hg spikes may also indicate loading of toxic metals to the environment that would be a contributing cause to the mass extinction events.