Paper No. 38-3
Presentation Time: 8:00 AM-12:00 PM
METAMORPHIC CONTACT AUREOLES IN THE TRIASSIC HARTFORD BASIN: CARBON MOBILITY AND IMPLICATIONS FOR THE END-TRIASSIC MASS EXTINCTION
WALKER, Madison1, ALLMAN, Lindsi1 and STEWART, Emily2, (1)Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, (2)Department of Earth, Ocean, and Atmospheric Science, Florida State University, 1011 Academic Way, Tallahassee, FL 32304, Tallahassee, FL 32310
Large Igneous Province (LIP) emplacement causes dramatic changes to the Earth System due to the emission of greenhouse gasses, including carbon dioxide (CO2), to the Earth’s surface (Ernst et al., 2021). While many studies focus on volcanic degassing during LIP emplacement, decarbonation reactions also occur when sedimentary host rock is heated and metamorphosed by LIP intrusions. This process could release nearly 100% of sedimentary carbon, sufficient to drive a mass extinction level event (e.g., Heimdal et al., 2020, 2021). At a time when carbon emissions are at an all time high, understanding Earth’s geological history could be fundamental in anticipating the consequences of anthropogenic climate change. This project therefore focuses on metamorphic contact aureoles created during the emplacement of the Central Atlantic Magmatic Province (CAMP) which is related to the End-Triassic Mass Extinction.
While many projects have estimated metamorphic degassing during CAMP’s emplacement using thermodynamic models, we aim to produce observational data to track and quantify the release of methane and CO2 from sediment surrounding CAMP igneous bodies. Prior work has focused on sediments adjacent to sills and dikes, but basaltic lavas may also induce local contact metamorphism when erupted. We therefore report observations of samples collected beneath a CAMP lava flow in the Triassic Hartford Basin, Connecticut. Isotopic measurements of δ13C-Carb along with the percentage of calcite in these metasediments are used to track the movement of carbon during igneous emplacement and estimate the net carbon flux to the surface. Future work will include textural characterization and the use of multiple temperature proxies (e.g., vitrinite reflectance and/or graphite spectroscopy) to establish a T-t-CO2 history consider implications for the global carbon cycle.
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