Paper No. 9
Presentation Time: 11:00 AM

COMPARISON OF DISSOLUTION LAKES ON TWO BAHAMIAN ISLANDS: DUCK POND BLUE HOLE, ELEUTHERA AND BLUE HOLE FIVE, SAN SALVADOR AND THEIR IMPLICATIONS FOR CLIMATE RECONSTRUCTION AND LUCAYAN OCCUPATION


ROY, Zohra, Environmental Health Science and Policy, George Washington University, 2121 Eye Street, NW, Washington, DC, DC 20052, BENDER, Sarah, Department of Geology, The College of Wooster, Scovel Hall, Wooster, OH 44691, BERNARD, Miranda, Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, PARK BOUSH, Lisa, Geology and Environmental Science, University of Akron, Akron, OH 44325, MYRBO, Amy, LacCore/CSDCO, Department of Earth Sciences, University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, MN 55455, BRADY, Kristina, LacCore, University of Minnesota, 500 Pillsbury Dr SE, Minneapolis, MN 55455, BUYNEVICH, Ilya V., Department of Earth & Environmental Science, Temple University, Philadelphia, PA 19122, BERMAN, Mary Jane, Center for American and World Cultures, Miami University, Oxford, OH 45056, GNIVECKI, Perry L., Miami University, 571 Mosler Hall, Hamilton, OH 45011 and BROWN, Erik, University of Minnesota Duluth, Large Lakes Observatory, Duluth, MN 55812, zohraroy@gwmail.gwu.edu

Inland blue holes are dissolution lakes that form on carbonate islands and are tidally influenced by conduits connecting them with the marine system. Because they are responsive to sea level, coring blue holes can tell us about a lake’s depositional history as it relates to climate as well as anthropogenic changes through time. Two blue holes—Blue Hole Five (FIVE) and Duck Pond Blue Hole (DPBH)—were cored on San Salvador and Eleuthera islands, Bahamas, in 2012 and 2013, respectively. Basic limnological data were collected in each lake and coring transects were done using square rod piston corers. The blue holes were similar in size (.001 km2), depth (5-6 m) and salinities (20-28 ppt). Age models based on radiocarbon dating yield a sediment record of ~6,000 years in both. Sediments in both lakes were dominated by carbonate sand ranging in size from 100-240 µm. Downcore data indicates grain size changes along with mollusk distribution that is likely linked to sea level. Mollusk faunas are similar between the two blue holes and include three species of bivalves (Anomalocardia auberiana, Ervilia concentrica, and Polymesoda maritime) and eight species of gastropods (Acteocina sp., Batillaria minima, Cerithidea costata, Cerithium lutosum, Haitia cubensis, Heleobops sp., and Sayella sp., and Semele proficua). Community structure appears to be similar between the two. X-ray fluorescence (XRF) scans of cores from both lakes at 0.5 cm intervals reveal negatively co-varying trends downcore between Fe and Ca in both lakes. There is an overall increase in Sr in both lakes that is independent of Ca and corresponding with increases in organic matter. We used depths of mollusk beds in both lakes to reconstruct a sea level curve for the past 6000 years BP. Both curves indicate a rapid rise at 2500 cal yBP that has not been previously reported from the Bahamas. This record corresponds with other regional and global records for the mid to late Holocene and influences the model of occupation of the Lucayans within the Bahamian archipelago.