GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 266-12
Presentation Time: 9:00 AM-6:30 PM


KING, Courtney C.1, HALL, Brenda L.1, STONE, John O.2 and HILLEBRAND, Trevor R.2, (1)School of Earth and Climate Sciences & Climate Change Institute, University of Maine, Orono, ME 04469, (2)Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195,

During the last glacial maximum (LGM), the Antarctic Ice Sheet (AIS) expanded and grounded across what today is the Ross Sea, forming the Ross Sea Ice Sheet. This ice mass caused tributary outlet glaciers from East Antarctica to thicken and expand into formerly ice-free valleys of the Transantarctic Mountains. Surficial deposits laid down by these expanded glaciers afford insight into the history of past expanded ice, as well as bear on the potential future behavior of the AIS. To study the evolution of the Ross Sea sector of the AIS, I mapped surficial geomorphologic deposits at three sites alongside Hatherton Glacier, an outlet of the AIS. I produced a chronology for these deposits from radiocarbon dates of subfossil algae from associated relict ice-dammed ponds. Radiocarbon chronologies from each of the three sites indicate that the last maximum extent of Hatherton Glacier was achieved in the early Holocene. Moreover, the glacier maintained a steady rate of retreat during the subsequent recession, without any evidence of catastrophic ice loss. These data, along with precisely constructed chronologies from other outlet glacier systems, may be input into geophysical models to assess the future behavior of the AIS in the Ross Sea region.