Late Holocene stable isotope chronology and meltwater discharge event in Maxwell and Admiralty bays, King George Island, Antarctica

Abstract

Two short gravity cores were retrieved to obtain palaeoclimatic information from Maxwell and Admiralty bays, King George Island, South Shetland Islands. AMS ¹⁴C age dates, sediment properties (grain size, TOC and CaCO₃) and stable oxygen and carbon isotope compositions of benthiδ foraminifera (Globocassidulina biora) show downcore variations that characterize depositional conditions during the late Holocene. In particular, δ¹⁸O values of benthic foraminifera are lowest at approximately 2500 yr bp in both cores. Allowδ¹⁸O time-equivalent excursion in both cores is interpreted to reflect a distinct subglacial meltwater discharge intensified by warm climatic conditions. An increased proportion of fine-grained detritus and higher TOC in the cores at this level suggests that enhanced meltwater supply may have resulted in increased primary productivity. This meltwater discharge event provides evidence of climatic instability during the late Holocene at King George Island.