DOES SEA LEVEL CHANGE INFLUENCE CARBON ISOTOPIC TRENDS IN THE LATE PERMIAN DELAWARE BASIN?

Previous studies from modern and ancient carbonate settings have argued that stable carbon isotopic trends can be influenced by changes in relative sea level. Explanations for this relationship focus on sea level’s control on processes like organic carbon burial, basin restriction, carbonate deposition/weathering/mixing, and freshwater input. As sea level rises, the basin becomes well mixed, organic carbon burial increases, aragonite deposition increases, and the influence of freshwater is diminished. This results in increasing carbon isotopic values in the carbonate rocks that form at the time. In contrast, when sea level falls, these processes work in reverse and carbon isotopic values progressively decrease. While previous studies have argued for such a systematic relationship between sea level and carbon isotopes, those interpretations have not been tested quantitatively. For this project we aimed to propose a statistical test for correlation between sea level and carbon isotopes in the Late Permian Delaware Basin. We focused our efforts on the Tansill and Yates Formations exposed in Guadalupe Mountains National Park and Carlsbad Caverns National Park. By pairing high resolution carbon isotopic records with the established sequence stratigraphic framework for these study locations, we performed a series of regression analyses to test for correlation between sea level change and carbon isotopic trends. Our results provide a new method for determining if sea level is influencing carbon isotopes.