DO CARBON ISOTOPIC VALUES VARY ALONG THE LATE PERMIAN DELAWARE BASIN SHORELINE?

In modern carbonate platforms like the Great Bahama Banks and Florida Bay, the carbon isotopic value of dissolved inorganic carbon (DIC) can vary by up to 2‰. This is due to a combination of factors like freshwater input, terrestrial organic carbon, and non-equilibrium conditions with the atmosphere. How these variations in the carbon isotopic value of DIC get recorded in the carbonates that form in these settings has important implications for our use of the record as a paleoclimatic and chemostratigraphic tool. In this study we explore how relative position along shoreline impacts the recorded carbon isotopic values in the Late Permian Delaware Basin. We targeted the Yates and Tansil Formation exposed in Walnut Canyon and the Permian Reef trail in Carlsbad National Park and Guadalupe Mountains National Park, respectively. These two sections represent roughly the same position relative to shore but were separated by ~40 km laterally. By examining the carbon isotopic records of these two sections we were able to demonstrate that there are not significant lateral variations in carbon isotopic values and trends.