The Last Interglacial, or Marine Isotope Stage (MIS) 5e (129–116 thousand years ago (ka)) was one of Earth’s most recent relatively warm intervals. Global mean sea levels are estimated to have been 5–10 m higher during MIS 5e than present; however, the potential contributors to higher sea levels during this interval, such as the loss of the West Antarctic Ice Sheet, remain poorly constrained. Here we present a high-resolution record of dust composition from an ice core at the Allan Hills Blue Ice Area, Antarctica spanning the Penultimate Glacial (MIS 6) through MIS 5e. Geochemical data show that MIS 6 dust is dominantly sourced from South America, whereas MIS 5e dust contains young volcanic material sourced from the McMurdo Sound sector of the West Antarctic Rift System and nearby, ice-free outcrops of the Transantarctic Mountains. Earth system model simulations show that loss of the Ross Ice Shelf and diminished West Antarctic Ice Sheet extent during MIS 5e would increase near-surface wind speeds and precipitation along an exposed Ross Sea coastline, strengthening dust transport from proximal Antarctic sources. The agreement between the modelled circulation changes and the observed provenance shift driven by changes in wind and surface exposure suggests ice-free conditions in the Ross Sea during MIS 5e, with possible West Antarctic contributions to the elevated sea levels of this period. Dust derived from Antarctic sources measured in an ice core from the Allan Hills spanning the peak of the Last Interglacial suggests that the Ross Sea was probably open at the time, coincident with a reduction in the volume of the West Antarctic Ice Sheet.
Carter et al. (Mon,) studied this question.