Abstract:
A shallow sediment core taken from the center of Salt Pond, an evaporite lake on eastern San Salvador island, has produced a record of benthic formainiferal faunal changes through time. The core is 83 cm in length and is considered to represent approximately 1.9 kyr. Salt Pond is near sea level and is separated from the shoreline by a dune ridge.Benthic formaminiferal assemblages identified from samples at 1 cm intervals include a low diversity assemblages characterized by Ammonia parkinsoniana, a low diversity assemblage characterized by Quinqueloculina bosciana, and a high diversity assemblage with abundant rotalids. The Ammonia parkinsoniana assemblage has not been found in other interior lakes on San Salvador. It is thought to represent the typical hypersaline phase in the history of Salt Pond, either as an interior lake or as a restricted lagoon. The rotalid assemblage occurs in distinct layers throughout the core and is thought to represent normal open marine conditions.The rotalid assemblages are found with faunal elements of the miliolid assemblage and the species of the rotalid assemblage do not persist vertically in the core but are restricted to 1 cm or less. The origin of these normal marine indicators within the sediment record of Salt Pond is interpreted to represent washover events associated with large tropical storms. This interpretation is consistent with the proximity of Salt Pond to the present day shoreline, the nature and distribution of the rotalid assemblage within the core, and current studies on sediments of Salt Pond.
