Southeastern Section - 62nd Annual Meeting (20-21 March 2013)

Paper No. 2
Presentation Time: 8:00 AM-5:30 PM

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


MATSUNAGA, Aya1, ASHWORTH, Henry1, BROOKS, Gregg1, LARSON, Bekka1, SCHWING, Patrick2, CLARK, Nichole1 and HOLMES, Charles W.3, (1)Marine Science, Eckerd College, 4200 54th Avenue South, St. Petersburg, FL 33711, (2)Marine Science, University of South Florida, St. Petersburg, FL 33701, (3)Environchron, 9103 64th Ave East, Bradenton, FL 34202, amatsun@eckerd.edu

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.