Abstract: During the late Quaternary, climate changes drove the advance and retreat of ice shelves in and around the Antarctic. Icebergs carried iceberg rafted debris (IRD) by calving, floating, and melting into the ocean. The large amount of melt water altered the structure of ocean water profiles and activities, which also affected the deposition of IRD. The association between IRD events and bottom current activities is not yet fully understood. Here, we present a sediment record retrieved from the northwestern Weddell Sea. Obvious peaks of four-IRD events were observed parallel with four bottom water enhancement events, based on a precise comparison of grain size data and End Member Model Analysis. These synchronous events revealed a coupling mechanism between the ocean and glacial systems. Two strong washing events supported the existence of two discontinuities of sedimentation, which explained the age difference between the paleomagnetism reverse and the AMS¹⁴C data. As the very low export productivity was similar to that at a glacial level, we deduced that most of this core was deposited in the last glacial period. The millennial temperature increases in the Antarctic triggered ice shelf retreats and led to obvious IRD events and bottom current activities.

Key words: grain size, ice rafted debris, productivity, sediment, Weddell Sea