METAL LOADING ON NW PANGEA DURING THE LATEST PERMIAN EXTINCTION –TOXIC CLOUDS FROM THE SIBERIAN TRAPS?

Volcanic eruptions are associated with significant release of trace metals to the atmosphere (e.g. Cu, Zn, Ni, Pb, Cd, Hg, As). While this has been suggested for the Siberian Trap eruptions, as a contributing cause for the Latest Permian Extinction, shifts to anoxic conditions at this time could also have led to localised metal enrichments through enhanced draw down. This creates difficulty in elucidating potential enhanced metal deposition related to increased volcanic loading rates. However, the well exposed latest Permian strata at Festningen, Spitzbergen, provides new insight for impacts of the Siberian Trap eruptions on NW Pangea.

The extinction boundary at Festningen, marked by loss of siliceous sponges, coincides with significant spikes in trace metals above average shale values, including Cu, Pb, As, Co, Ni, Hg. These spikes occur prior to a shift to more anoxic conditions, showing they are timed with the extinction event but immediately precede the shift to marine anoxia. These results are consistent with other locations in NW Pangea (Sverdrup Basin) that show high metal loading rates at the extinction boundary, which we argue are related to enhanced volcanic emissions. Actual rates depend on estimates on eruption history, but even at conservative levels would represent significant and potential toxic loading of metals into marine environments at that time.