SGER: Tropical Tidal Flat Archive of Global Climate Variations

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This is an SGER (Small Grants for Exploratory Research) award. Tropical tidal flat deposits of the Western Atlantic may contain a unique strip-chart-like record of variations in climate during the past few thousand years. The locally-adhesive surfaces of these flats act like fly-paper to retain aerosols from Africa and centimeter-thick layers of marine sediment record the passage of hurricanes. Both the frequency of hurricanes and the flux of aerosols from Africa reflect global-scale variations in climate. To explore this potential record of climate variations, a series of cores will be collected for sediments that have accumulated continuously for the past 3000 years or more. The sediment layers that record major storms will be logged and their compositions determined; the aerosols will be extracted from the inter-storm algal layers, weighed and their compositions determined by x-ray diffraction and optical microscopy. To date the storm layers and determine rates of accumulation of aerosols, sections of the cores will be dated by radiocarbon and possibly with thorium230. This pilot project may produce a local record of hurricane frequency and the flux of aerosols and by applying the method to other tidal flat deposits, it is possible to develop the record of a much larger area. This exploratory research is important because, if successful, it will provide information of storm frequency under different global climate regimes.