US Geological Survey


Date of this Version



Published in micropaleontology, vol. 39, no. 1, pp. 29-45, plates 1-7, text-figures 1-2, table, 1, 1993.


An exceptionally well-preserved early Oligocene diatom assemblage is documented and illustrated from the internal sediment of a gastropod shell, which was collected from glacial sediments recovered at Ocean Drilling Program Site 739 on the continental shelf in Prydx Bay, Antarctica. The diatoms were deposited between 35.9 and 34.8 Ma according to diatom and calcareous nannofossil stratigraphy, apparently soon after a period of major ice sheet advance across the Prydz Bay continental shelf. The diatom assemblage is neritic in character. but it can readily be correlated with open ocean assemblages from the Southern Ocean as well as with similar material recovered from the CIROS-I drillhole in the Ross Sea.