FORAMINIFERAL AND OSTRACODAL ASSEMBLAGES FROM TRIANGLE POND, SAN SALVADOR ISLAND, BAHAMAS: A STUDY IN QUANTIFYING THE QUALITY OF MICROFOSSIL ASSEMBLAGES TO IDENTIFY DEPOSITIONAL ENVIRONMENTS

Triangle Pond is located on the northwestern coast of San Salvador Island, Bahamas, and at present, the lake is brackish to hypersaline and dominated by algae. In 2009 five soft sediment cores were removed from the deepest part of the lake, and in 2013 five more sediment cores were removed from along the inside of the seaward dune. An in depth paleolimnological examination of the ten cores established six different past environments with each unit being defined by sediment composition, color and texture. Two of the six units were dominated by marine input; however, the composition of these units indicates two different types of environmental deposition. A fining upward sequence, bimodal deposition and an erosional contact with the underlying peat layer indicates that the upper marine layer was deposited quickly in a catastrophic event. The lower marine layer, located beneath the layer of peat, shows a consistent deposition of poorly sorted grain size dominated by fine sands and silts indicating that the deposition of this layer was slower and lasted for a period of time. To further differentiate the two units dominated by marine input, a systematic examination of ostracod and foraminifera assemblages was undertaken. The microfossil assemblages show that not only are the different species of the microfossils indicative of environmental factors, but the condition and variance in the fossils can help specify the mode of deposition.