Late Quatenary Paleoceanograpic Study Of The Northern Continental Slope Off The Prydz Bay, Antarctic

Our work focuses on the P1-03 gravity core sediment sampled in the northern continental slope off the Prydz Bay during the Chinese 30 th Antarctic Scientific Expedition. By discussing the factors influencing sedimentation in modern times, sediment provenance and paleoceanographic features in this area, several conclusions were as drawn as follows:(1)In 520 thousand years there were 8 large ice rafted debris events. Environment sensitive grain size components in sediments of core P1-03, recovered from the continental slope off the Prydz Bay, were analyzed. Eight ice-rafted debris events were identified in the core for the past 520 ka, which mostly occurred in glacials and relatively cold periods in interglacials. It shows that cold climate is propitious to the accumulation and expansion of glaciers. The disintegration in the expansion process of the ice shelf makes a lot of icebergs into the sea, resulting in sediment flux of ice rafted debris increased.(2)The results of a comparative study of the P1-03 core fine grained clay with the Dome C ice core dust flux records and the ice melt water discharge indicated that the late Quaternary East Antarctica ice edge-sea-air interaction is obvious, and the dust and underflow both constraint the sediment of fine sensitive components. Although in the glacial period the increase of fine clay is affected by the dust flux, it also has relationship of ice melt water which discharged into the slope area when the ice shelf expansion to north.(3)Discussed the evolution characteristics of water masses and circulation in the study area during the glacial and inter glacial period.Contents of sortable silt and clay fractions reflect the strength of bottom currents. Their cyclic variations indicated that the bottom currents were relatively weak and benefit for clay deposition during ice ages, while strengthened during interglacial stages, together with the southward shift of the main axis of the Antarctic Circumpolar Current, and the increased water exchange between shelf and slope.(4) The palaeo-oceanography oxidation environmental and productivity characteristics in the study area were analyzed. The productivity of the study area is mainly affected by sea ice, glaciers, currents and the terrigenous matters flux. In glacial periods, with the bottom melting glaciers and sea ice cover, terrigenous matters flux is low, palaeoproductivity is mainly affected by marine phytoplankton. During interglacial period, as the disappearance of the landing glaciers and the southward movement of covered sea ice, the hydrodynamic conditions will strengthen and terrigenous flux will increase lead to the paleoproductivity increasing.