This study seeks to develop a technique to determine exposure ages and erosion rates of bedrock surfaces by studying, by accelerator mass spectrometry, the history of production in situ, radioactive decay, and erosional loss of the cosmogenic radionuclides Be and Al in quartz samples from those surfaces. Preliminary measurements on a variety of samples indicate that Antarctic bedrock surfaces retain very high concentrations of Be and Al, apparently a consequence of very slow erosion rates. This technique is now ready for application in a systematic way on a suite of 73 samples of quartz-rich rock from the dry valleys of the Antarctic and from a sedimentary veneer on the Elephant Moraine. Be and Al concentrations will be measured in quartz separated from those samples to determine the extent of prior glacial cover of bedrock surfaces now exposed and the chronology of accumulation of moraine particles on the surface of the Elephant Moraine. This investigation will be a collaborative effort by scientists at the University of Pennsylvania and Ohio State University.
