Testing Magma Intrusions into Black Shale as a Trigger for the PETM Carbon Isotope Excursion



Fifty-six million years ago Earth experienced rapid global warming that was caused by the release of large amounts of carbon into the ocean-atmosphere system.  This Paleocene-Eocene Thermal Maximum (PETM) is often cited as an analogue of anthropogenic climate change.   Many trigger mechanisms for the carbon release at the PETM have been proposed.  Common to all scenarios is rapid release of isotopically light carbon from methane hydrates, cometary, terrestrial or marine organic matter, as indicated by a pronounced excursion to light carbon isotope values across the PETM.

Together with JP student Andrea Dubin, I propose to test the hypothesis that PETM warming and isotope excursion were caused by intrusion of magmatic sills into organic-rich sediments.   The intrusion of hot magma into sedimentary rocks caused metamorphic reactions in a thermal aureole around the intrusion.  If these sediments are rich in organic matter, large volumes of isotopically light carbon dioxide could be released quickly.  Here, we propose to scrutinize inorganic evidence of magma-sediment interaction in marine PETM sections.