Controls on Calcium Isotopes in a Cold Seep Barite Sample from the Northern Gulf of Mexico Continental Slope.

Barite (BaSO4) - a common precipitate at cold seeps in the Gulf of Mexico continental slope - serves as an archive of calcium (Ca) isotopes. Calcium isotopes have proven to be a robust tool for studying biological and geological processes. However, there is limited information about the Ca sources and controls on its isotopic composition in barite which precipitates near the seafloor at cold seeps. This study will provide better understanding of the dominate factor(s) influencing the Ca isotopic signature of cold seep barites by (1) determining the likely Ca source and (2) identifying the main Ca isotopic controls in cold seep barites through the measurement of δ44/40Ca, 87Sr/86Sr, δ34S, and δ18O. Furthermore, results from this study could be used to better understand environments in early Earth, and potentially other planetary systems where barite is found.