HIGH-RESOLUTION SEDIMENTARY MERCURY RECORDS FROM THE ATLANTIC COASTAL PLAIN DURING THE PALEOCENE-EOCENE THERMAL MAXIMUM

The Paleocene-Eocene Thermal Maximum (PETM, ~56 million years ago) was an interval of rapid global warming that led to other global-scale biogeochemical feedbacks including but not limited to changes in evaporation-precipitation patterns, enhanced weathering, and increased wildfires, all of which had a significant impact on the flora and fauna of Earth. The PETM has been linked to increased carbon emissions from the emplacement of the North Atlantic Igneous Province (NAIP) through the application of the sedimentary mercury (Hg) proxy. Elevated sedimentary Hg enrichments have been interpreted to reflect the direct outgassing of volcanogenic Hg released during NAIP emplacement. Therefore, sedimentary Hg enrichments should be preserved on a global scale, unless there are other mechanisms controlling the Hg cycle during the PETM. To test the hypothesis that NAIP emplacement was the cause of the PETM through sedimentary Hg geochemistry, we have targeted several drill cores that preserve the PETM interval from the eastern North American paleo-shelf.

Several drill cores from the Atlantic Coastal Plain have been sampled for this study. Mercury concentration data were analyzed from Ancora, Clayton, and Wilson Lake B cores in New Jersey, and South Dover Bridge, Cambrian-Dorcester, and Howards Tract cores in Maryland. The Howards Tract cores contain the highest-resolution record of the PETM from this region of North America. In all locations, the PETM is represented by the Marlboro Clay, a silty-clayey unit that differs greatly from the underlying Aquia Formation (glauconite-rich sands) and overlying Nanjemoy Formation (clayey sands). The combined datasets will yield important insight into the PETM Hg cycle and the relationship between NAIP emplacement and sedimentary Hg enrichments.