509 / 2024-09-18 09:38:21

Tracing paleoceanographic archives of ice sheet-ocean interaction of the Drygalski Trough since Last Glacial Maximum, Ross Sea Antarctica

Drygalski Trough; Ross Sea; marine sedimentology; ice sheet dynamics; sediment cores; palaeoceanographic evolution; Antarctica.

The continental shelf of the Ross Sea holds three large subparallel sedimentary basins that are the Victoria Basin, the Central Trough, and the Eastern Basin. The deepest area of the continental shelf is located at the Drygalski Trough in the Victoria Basin, with a water depth over 1,100 m. Sedimentation in Drygalski Trough is mainly controlled by the past East Antarctic Ice Sheet (EAIS). Previous studies discussed the sediment facies and sedimentary environments, but the analysis of sediment source provenance is poor, transport dynamics and post-transport processes are not clearly, the correspondence between sedimentary events and paleoclimate changes still needs to be explored. We analyzed the grain size, XRF, biogenic silica, total carbon (TC), total nitrogen (TN), total organic carbon (TOC), Raman spectroscopy mineralogy, and isotope dating to obtain the information of the composition and access the sedimentation mechanism from the two new gravity cores collected in the Drygalski Trough by Chinese Antarctic Expedition. The preliminary results indicate that the sediments are characterised by coarse diamictons with low biological productivity during the glacial stage, and by clay and silt deposits with increased biological productivity during the interglacial stage. In addition, some of the thin interbedded deposits on the gravity core contain high amounts of ice rafted debris (IRD), presumably controlled by iceberg-marine depositional events. The adjacent cores support that Drygalski trough had received subglacial sediments since at least 30 ka. The aim of this study is to reveal the complicated paleocenographic conditions and ice sheet-ocean interactionc since the Last Glacial Maximum. The reconstruction of the past glacial activities and the evolution of the depositional environment in the Drygalski Trough provides key information for predicting the impacts of future glacier changes and improving the accuracy of glacier-ocean models.