Cosmogenic He in surface rocks is produced in situ by cosmic ray induced spallation reactions. As shown by recent studies of radiocarbon dated lava flows, measurements of cosmogenic helium can therefore be used to determine exposure ages. This research will apply the technique to glacial deposits in the Antarctic Dry Valleys. The goal of the research is to resolve some existing questions regarding the helium exposure-age method, and also to constrain the history of the Antarctic ice sheet and its relation to global climate. The Dry Valleys are ideal to test the technique because of uniquely exposed, well-dated moraines (Arena valley) indicate that quartz is a suitable mineral phase. The initial emphasis of the research will center on further measurements from dated moraines, and gaining a better understanding of the distribution and retention of helium within quartz. Quartz is such a ubiquitous mineral that this will be of general interest to glacial geology. Application of the technique to glacial deposits in the Ross Sea and glacially straited surfaces in the Transantarctic mountains will help elucidate the history of the Antarctic Ice Sheet.
