Late Holocene glacial advance and ice shelf growth in Barilari Bay, Graham Land, west Antarctic Peninsula

Abstract

Three marine sediment cores were collected along the length of the fjord axis of Barilari Bay, Graham Land, west Antarctic Peninsula (65°55'S, 64°43'W) during the first Larsen Ice Shelf System Antarctica (LARISSA) cruise (NBP10-01). Multi-proxy analytical results, including grain size, laminations and ice-rafted debris indices, organic geochemistry, magnetic susceptibility, water content and diatoms analysis, capture a record of Holocene paleoenvironmental variability. Constrained by high resolution geochronological methods (Pb-210, C-14) in concert with historical observations, our results suggest Early Holocene retreated glacial positions (> 7022 cal yr B.P.), followed by seasonally marine conditions with enhanced primary productivity during the Middle Holocene (> 2815 cal yr B.P.), seasonally marine conditions with increased sea ice coverage during the Neoglacial (2815 to 82 cal yr B.P.), Little Ice Age (~730 to 82 cal yr B.P.) glacial advance to maximum Holocene positions and development of a fjord-wide ice shelf, initial grounding line retreat and gradual recession of the ice shelf 310 cal yr B.P.., and modern seasonally marine conditions and loss of remnant ice shelves within the context of recent rapid regional warming (82 cal yr B.P. to present). Our findings agree with previously observed Late Holocene cooling and glacial advance in the west Antarctic Peninsula, further suggesting that the Little Ice Age was a globally manifested climate event, albeit with disparities in regional timing and magnitude.