Melting History of the Antarctic Ice Sheet since the Last Glacial Maximum Based on the Analysis of Sediment Cores around the Antarctic Peninsula, Southern Ocean

Abstract

We studied three sediment cores recovered from off the Antarctic Peninsula to reconstruct the melting history of the Antarctic Ice Sheet during the last 24kyrs. Ice Rafted Debris (IRD) and terriginous material from the Antarctic Continent were investigated throughout the cores to obtain the timing and magnitude of the melting events. We employed as a proxy the relative abundances of K₂O and Na₂O to understand the origin of the sediments. Surface sediments K₂O/Na₂O ratio correlated with the degree of the influence from three surface currents in the region, and hence the ratio can constrain the source area of the sediments. Chronologies of these cores were constructed based on both radiocarbon dating of sedimentary organic carbon and the relative abundance of radiolarian Cycladophora davisiana. Analyzing IRD, K₂O/Na₂O ratio, ¹⁴C, and radiolarian in the cores showed temporal variations of IRD flux as well as the source regions of the sediment supply from the LGM to the present. IRD maxima were observed at 25-17 and 15-12ka that show considerable expansion of the ice sheet during the LGM and rapid melting of the ice sheet at the time of the global meltwater pulse 1a event.