Late Palaeogene palynoflora from Point Hennequin of the Admiralty Bay, King George Island, Antarctica with reference to its stratigraphical significance

The present paper is to discuss the geological age and sedimentary environment based mainly on the characteristics of the palynological assemblage in the intercalated tuffaceous sand-mudstones of the Upper Point Hennequin Group in the Admirelty Bay, King George Island, Antarctica. More than 40 species, mainly the Late Paleogene plant community in Gondwana and belonging to Weddellian biographic Province, were encountered within the volcano-sedimentary rocks of the Upper Point Hennequin Group. The index member is the genus Nothofagidites. The occurrence of N. cf. saraensis and N. cf. flemingii and the absence of Proteacidites spp. indicates that the sporopollen-bearing rocks is of Oligocene age, which were deposited in a limnetic zone near medium-lower mountains environment with warm and humid climate

Late Quaternary glacial-marine sedimentation in the Bransfield Strait off northeast Antarctic Peninsula

Systematical analyses of lithology, grain size, mineral composition, micro-biological thanatocoenoses and other geological proxies from the sediments of piston core Pc10, drilled in the central part of the Bransfield Strait, have been carried out. Based on the above data, together with the shipboard investigation, the 753 cm long core sediments reveal the last 112.5 ka deposits of the study area under the glacial-marine environment. The sediments includes biogenic silica deposit, volcanic debris deposit and turbidity current deposit. Among them, the biogenic silica deposit is dominative not only in the highstand water/interglacial stage, but also in the lowstand water/glacial stage. The difference of sedimentation between the two stages was that the terrigenous debris content and the sedimentation rate were lower in the lowstand water/glacial stage

Silica oxygen isotope record of core PC10 diatoms from the Bransfield Strait, Antarctica and its application in sedimentology

51 diatom samples taken from the piston core PC10 in the Bransfield Strait of West Antarctica were determined by using silica oxygen isotope analysis. The diatoms-based results reveal that the 753 cm long core PC10 was deposited in the area in the last 112.5 ka B.P. , representing 1 - 5 oxygen isotopic stages and including one incomplete glacial/interglacial cycle and a postglacial period. The sedimentation rate in interglacial period seems to be a little higher than that in glacial, owing to the more terrigenous supply by ice-rafting during the interglacial stages

Paleomagnetism of Early Tertiary volcanics in the South Shetland Islands and its tectonic implications

A total of 334 oriented volcanic samples of Early Tertiary were collected for a paleomagnetic study from 43 sampling sites in the South Shetland Islands, Antarctica. Paleomagnetic study indicates that the South Shetland Islands and Antarctic Peninsula were situated in or close to their present position in Early Tertiary. Furthermore, it is also suggested that a counterclockwise rotation about 15 degrees related to the relative movement between South America and Antarctica took place in north of Antarctic Peninsula since Paleocene