A palynological investigation into palaeoenvironmental changes in the early Cenozoic sediments of Seymour Island, Antarctica
The Paleocene and Eocene sediments outcropping on Seymour Island, Antarctic Peninsula have been investigated for their dinoflagellate cyst and sporomorph content. The data have been quantitatively analysed to provide a high resolution study of palaeoenvironmental change with an emphasis on integrating the marine and continental records, as well as to update the biostratigraphical potential of the palynomorphs. Samples were collected from 10 sites across Seymour Island and the specimens were analysed to produce absolute abundance data and ratio curves of sporomorph/dinoflagellate cysts, Peridinioid/Gonyaulacoid dinoflagellate cyst and species richness and absolute abundance. The count data were also analysed statistically by Correspondence Analysis to provide further details of species abundance and composition within assemblages in order to highlight palaeoenvironmental change and its impact. The evidence suggests widespread dramatic changes in marine conditions in the earliest Danian, before more stable conditions developed which may be related to climate warming in the Late Paleocene. Marine conditions also varied widely in the Eocene, but these appear to have been more localised changes relating to regional tectonic activity, while the climate seems to have undergone small-scale warming and cooling events. Evidence exists for the existence of a cooling trend in the lowermost Paleocene. Following a mid-Paleocene sedimentary hiatus, both marine and terrestrial palynomorph data suggest the location of the Eocene Climatic Optimum within the lower La Meseta Formation. Climatic cooling, presumably linked to the development of the cryospherc as the continent became isolated, is also observed.