Ostracoda from Vestfold Hill Lake Terraces, Antarctica

Abstract

Six species of ostracodes are recorded from two transects of terraces of Deep Lake, Vestfold Hills, Antarctica. Two species (Xesteleberis sp. and Bradleya dictyon) range from Cretaceous to Recent, Poseidonamicus aff. P. major ranges from Oligocene to Recent, while Krithe tunnida ranges from Pliocene to Pleistocene to Recent. Paradoxostoma antarcticum and Loxoreticulatum fallax are reported from Antarctica and range from Pleistocene to Recent. Bradleya and Krithe were typical deep water (psychrospheric) forms during Paleocene to Oligocene as today but they were found in shallow (-45 to -37 m) depths here. Ostracodes are extremely rare as compared to the associated foraminiferal assemblage. Dissolution effect, loss of ornamentation, thinning and fragmentation of the fauna are considered to be mainly due to gradational external stress, and large scale physical environmental shifts such as high salinity, low temperature and high dissolved carbon dioxide content of the Deep Lake waters. Disparity in abundance is attributed to wind erosion, differential deposition after ablation of ice from ice sheets, physiographic variation of the region and high rate of dissolution of calcareous forms including foraminifera.