Palynology of Leg 28 Drill Sites, Deep Sea Drilling Project

Abstract

Palynological examination has been made of a total of 101 core samples from Sites 264, 266, 268, 270, and 274 from Leg 28. At Site 270, preglacial carbonaceous and glauconitic sand units yielded few palynomorphs, except for a sparse assemblage of Oligo-cene dino-flagellate cysts from the greensand unit. In the overlying glacial-marine unit at this site, basal sediments of late Oligocene age yielded spore and pollen assemblages which seem likely to be in situ, rather than recycled. These assemblages are dominated by Notho-fagidites, with subsidiary podocarpaceous,.proteaceous, and myr-taceous pollen, and suggest a parent vegetation showing little floristic change from that known from Eocene erratic siltstones at McMurdo Sound. It is suggested that such vegetation persisted into the earliest phases of glaciation. The same units yieldpd rare dino-flagellate cysts, including Selenopemphix nephroides, a form which has hitherto only been recorded from the mid to late Oligocene of northwest Europe. Basal silty units at Site 274 yielded rich dinoflagellate assemblages , probably of late Eocene age. Several species of this assemblage persist into the overlying diatom-rich unit of Oligocene age. The dinoflagellate suites are similar to those from the McMurdo erratics and to those from the Rio Turbio Formation of Patagonia and form part of a distinctive austral floral province. Very little palynological material, apart from abundant leio-spheres, was recovered from the pelagic Sites 264 and 266 and from the near-continent Sites 268 and 269. The scarcity of palynomorphs at these sites may be due to excessive dilution by pelagic remains and terrigenous detritus.