This award is for support for a three year study to use surface exposure age dating (cosmic ray produced nuclides such as Helium3, Neon-21, Beryllium-10 and Aluminum-26) to determine the timing of glacial advances and retreats in two regions of AntarcticaMcMurdo Sound and Shackleton Glacier. A combination of careful field work and extensive laboratory studies are needed to test this relatively new dating technique and to answer questions about the glacial history of the Transantarctic Mountains. The goals of the project are to improve age determinations of the youngest Ross Sea Drift in McMurdo Sound, to calibrate production rates of cosmogenic nuclides with new Helium-3 measurements on Argon dated lava flows and man made targets, to extend the glacial chronology of the Ross Ice Sheet to other areas and age ranges and to constrain the age of the controversial Sirius group deposits.