REFINING ANNUAL-SCALE 228TH AND 234TH GEOCHRONOLOGICAL TOOLS: APPLICATION ON THE 2010 BP BLOWOUT EVENT

The 2010 Deepwater Horizon blowout event released ~5 million barrels of crude oil into the northeastern Gulf of Mexico. The fate of discharged oil, especially subsurface oil, still remains in question, but short-lived radioisotope geochronology utilizing ²¹⁰Pb (half-life ~22.3 years) and ²³⁴Th (half-life ~24days) showed that surficial sediment accumulation rates increased in excess of one order-of-magnitude over rates of underlying “natural” sediments. Since over two years have passed since the event, ²³⁴Th can no longer be used to track the original event. This study investigates the use of ²²⁸Th (half-life ~1.91 years) as a geochronological tool to continue studying DWH sediment impacts. Initial work focused on refining techniques to determine background and improving the accuracy of not only ²²⁸Th, but also ²³⁴Th. While work is still in progress, ²²⁸Th appears to be a promising an annual-scale geochronometer to investigate sedimentary processes over a range of time scales, and especially potential impacts of the 2010 BP blowout event.