Dust climate couplings in Iceberg Alley – first results from IODP Expedition 382

Abstract:

Expedition 382 (Iceberg Alley) aims at improving our understanding of how the coupled Antarctic ice–ocean–atmosphere system evolved to the present state. The expedition took place from March to May, 2019 and retrieved three sites (U1536, U14537 and U1538) in the southern Scotia Sea. The main goals are to investigate the dynamics and temporal variability of the Antarctic Ice Sheet mass loss, to better understand changes in oceanic and atmospheric circulation, and global sea level during the Plio-Pleistocene. Key time slices include the mid Piacenzian warm period, the late Pliocene glacial expansion of the West AIS, the mid-Pleistocene transition, the mid-Brunhes event, superinterglacials and the glacial terminations of the last 800 ka.

At Site U1537 we recovered the most continuous and highest resolution marine archive of dust and ocean productivity proxies ever obtained near Antarctica for the Plio-Pleistocene. First results indicate that changes in dust proxy records between the Scotia Sea and Antarctic ice cores are closely tied and therefore that IODP Expedition 382 records have the potential to provide a detailed reconstruction of changes in the Southern Hemisphere westerlies on millennial and orbital timescales far beyond the current reach of 800,000 years provided by Antarctic ice cores. Extending the ocean dust record beyond that time will help to evaluate climate-dust couplings since the Pliocene, the potential role of dust in iron fertilization and atmospheric CO₂ drawdown during glacials, and whether dust input to Antarctica played a role in the mid-Pleistocene transition. Concurrent studies on ocean productivity allow us to further assess the role of the high-latitude Antarctic Zone of the Southern Ocean in regulating atmospheric CO₂ during glacial-interglacial cycles.