CONSTRUCTING A DEPOSITIONAL HISTORY OF STORM INFLUENCE FOR COASTAL PONDS OF SAN SALVADOR, BAHAMAS

The Bahamian island of San Salvador, the eastern-most platform of the Bahamian archipelago, is subjected to frequent hurricane activity. Numerous low-energy, hypersaline ponds are scattered throughout the island’s coastal regions. High-energy storm events generate surges and high winds that create distinct sedimentologic signatures to deposits within these sediment sinks. Storm layers are distinguishable from ambient sedimentation through facies interpretation and microfossil content; whereas the stagnant ponds ordinarily only sequester organic and clay materials, storms bring in carbonate beach sand and species of foraminifera that live only in reef environments.

Prior research has focused on resolving a storm history from pond cores collected along the eastern side of the island. A high degree of sedimentologic heterogeneity found within different ponds in close proximity infers that no single location contains a complete record. This is because factors such as shoreline orientation, coastal morphology, vegetation density, and nearshore bathymetry heavily influence storm-induced sedimentation. The scope of investigation is now expanded to include locations from across the island to reconcile records and elucidate a more complete history of storm influence on San Salvador.

Research currently underway is reconstructing depositional patterns across the island by analyzing additional push-cores from select ponds, which will help determine temporal and spatial coherence. Requiring an accurate chronology to evaluate storm deposits within a spatio-temporal context, samples will be analyzed for Cs¹³⁷ and Pb²¹⁰ activity to provide information on the timing of storm activity, inferred from high-resolution grain-size and microfaunal studies. Ongoing investigations will further reconstruct island-wide depositional patterns while reconciling records to yield a more complete chronology of historic storm events in the region.