2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 197-7
Presentation Time: 9:40 AM


WALLACE, Davin J.1, DONNELLY, Jeffrey P.2, WOODRUFF, Jonathan D.3, VAN HENGSTUM, Peter J.4, ROSENHEIM, Brad5 and HORGAN, Meghan C.4, (1)Department of Marine Science, University of Southern Mississippi, 1020 Balch Blvd, Stennis Space Center, MS 39529, (2)Geology & Geophysics Department, Woods Hole Oceanographic Institution, MS #22, 266 Woods Hole Rd, Woods Hole, MA 02543, (3)Department of Geosciences, University of Massachusetts Amherst, 611 North Pleasant St, 233 Morrill Science Center, Amherst, MA 01003, (4)Department of Marine Sciences, Texas A&M University at Galveston, 1001 Texas Clipper Road, Galveston, TX 77554, (5)College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701, davin.wallace@usm.edu

Due to relatively short instrumental observations, paleohurricane records can be useful for extending our knowledge of hurricane response to known variable climatic and oceanographic conditions in the past. By carefully selecting new sites from around the world, additional insights can be gained towards a more complete understanding of basin-wide hurricane trends. Here we highlight a paleotempestological study from Mangrove Lake (ML), Bermuda. Due to the unique offshore location of Bermuda in the western Atlantic, this site contains information about northeastwardly recurving Atlantic storms. ML currently has a flooding height threshold of 7 meters above sea-level, being separated from the ocean by stable Pleistocene-age eolianites. Therefore, it is likely that storms preserved in this setting represent large inundation events. Based on nearly 30 rapid turn-around gas ion source AMS radiocarbon dates, four conventional AMS ages, and short-lived isotopic accumulation rates, a Bayesian statistical age model is constructed. We will discuss the multiproxy paleotempestological approach consisting of X-radiographs, X-ray fluorescence, micropaleontology, and grain size measurements in the context of the ~2,000 year age model to estimate the frequency, intensity, and timing of storms. Preliminary data from the lake show numerous coarse-grained deposits containing the offshore forminifer Homotrema rubrum, interpreted as storm-induced transport. The timing of these deposits suggests elevated periods of hurricane activity occurred between ~500 and ~1,000 yr BP using the standard marine reservoir radiocarbon correction. ML could provide valuable insight concerning Atlantic hurricane variations due to changing North Atlantic Oscillation-like conditions and regional oceanographic changes. Furthermore, this site could shed light on regional storm trends through a comparison with established records.