Paper No. 8
Presentation Time: 10:45 AM
A 5000 YEAR HURRICANE HISTORY FROM A SHALLOW COASTAL POND, ELEUTHERA, BAHAMAS AND ITS EFFECT ON LUCAYAN OCCUPATION
Hurricane intensity has been linked to climatic changes and El Niño throughout the Holocene. We recovered a >5000 year storm record from sediment cores within a shallow, hypersaline coastal lagoon on the island of Eleuthera, Bahamas. Cores from three sites along a transect perpendicular to ocean shoreline were collected and analyzed through geophysical logging, digital imaging, radiocarbon dating, smear slide and SEM analysis, grain size distribution, loss on ignition and X-ray fluorescence (XRF). Lake sediment lithofacies are dominated by microbial mats, sand layers, and containing basal peat deposits. The sand layers are between 0.02mm-2cm thick, occurring as interbeds within the microbial mats and are composed of allochthonous carbonate sand and shelly material that resemble the modern beach facies and are therefore interpreted as being overwash deposits from large storm events. Downcore, mean grain size distribution reveals a storm record history with a recurrence interval of 0.008/year (125 years). Loss on ignition also reveals a change in organic matter and carbonate content. XRF scans at 0.5cm intervals show a Ca record that correlates with the sandy intervals and a Fe record that reflects aerosol dust originating from Africa. Integrating these proxies reveals a hurricane record that shows a marked intensity between 3400 and 1000 yBP that has been previously documented as a ‘hurricane hyperactivity period’ by Liu and Fearn (2000) and Park (2012). A relatively quiet period followed during the Medieval Warm Period that corresponds with the arrival and subsequent occupation of the Lucayan people. Dune emplacement history revealed by GPR profiles suggest that origination and progradational development might have been initiated and controlled by storm events.