Tuesday, 7 October 2008: 10:30 AM
George R. Brown Convention Center, 322AB
A high-resolution record (0.8cm/year) of Holocene deglacial and climate history was obtained from a 77m sediment core from the Firth of Tay, Antarctic Peninsula (AP) as part of the SHALDRIL initiative. This study provides the first detailed sedimentological record of Holocene paleoclimate and glacial advance and retreat from the Weddell Sea side of the AP. A robust chronostratigraphy was derived from 31 radiocarbon dates on carbonate material. This chronostratigraphic framework is used to establish the timing of glacial and climate events derived from multiple proxies: including magnetic susceptibility, grain size, ice-rafted debris, organic carbon, diatoms, and foraminifera. The core bottomed-out in a stiff diamicton interpreted as subglacial till. Gravelly and sandy mud above the till is interpreted as proximal glaciomarine sediment that represents decoupling of the glacier from the seafloor and landward retreat. The core site remained in a proximal glaciomarine setting until ~7750 cal. yrs. BP, at which time significant glacial retreat took place. Open marine conditions lasted until present, with minor glacial advances having occurred between 6020 to 4810 and 3780 to 1630 cal. yrs. BP. There is no evidence for an ice shelf having existed in the area following initial glacial retreat from the fjord. Climatic intervals such as the Little Ice Age, Medieval Warm Period, Neoglacial, Holocene Climatic Optimum, and Climate Reversal, which are observed in the western AP, are not as prominently recorded in the Firth of Tay. This indicates that the eastern and western sides of the AP may have experienced different climate histories during the Holocene.