Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


An investigation of organic-walled microplankton from the only known outcrops of Lower Tertiary marine sediments on the Antarctic continent has been completed. Seventy samples collected from seven stratigraphic sections through the Paleogene Seymour Island deltaic complex were examined. Forty-four dinocyst genera and 75 species were recovered, of which 2 genera and 10 species were new. Specimens attributable to the Acritarcha, Pterospermatales, and Chlorococcales also were noted. Dinocyst analysis indicated the sediments of the Cross Valley Formation, in the Cape Wiman area, were laid down during the early late Paleocene Epoch. The deposits at the type section in Cross Valley are biostratigraphically suspect due to known, but only partially mapped, faults in the area; these sediments were deposited during the Paleocene-Eocene epochs. The deposits of the La Meseta Formation were laid down during the early Eocene and middle to late Eocene epochs. Deposition occurred within the subenvironment of the various deltas which constitute the Seymour Island deltaic complex. Deposition occurred within distributary channels, interdistributary bays, lagoons and, perhaps, prodelta areas. The dinocyst floras are composed of cosmopolitan and provincial taxa. The former have been reported from regions as widely separated as Europe and Australia. The provincial flora, previously named the transantarctic flora, was well developed in and around Antarctica by the Eocene Epoch. The distribution of the transantarctic flora suggests that a strait connecting the southwest Atlantic and southwest Pacific oceans existed during the Eocene Epoch. Maceral and TOC analyses indicate potential hydrocarbon source rocks exist in the Seymour Island area. However, all of the samples studied are thermally immature or only entering early thermal maturity. More mature source rocks may lie below Seymour Island or in offshore areas.