Posted on Feb 15, 2002

Donald Rodbell, associate professor of geology, is one of
four researchers to receive a $20,000 grant from the National
Geographic Society for a project titled “The Pacing of Tropical
Glaciation.” (Others are Geoff Seltzer and Jacqueline Smith of
Syracuse University, and Robert Finkel of Lawrence Livermore National
Laboratory.) The group is to use a relatively new technique to
date glacial deposits in the Andes Mountains. The hope is to
better understand the relationship between the timing of
climate change in the tropics with that at higher latitudes of both
hemispheres. The technique, called cosmogenic exposure dating,
allows the scientists to determine the time of exposure of boulders on
glacial materials to determine when they were deposited. The
accumulation of certain isotopes produced only by the exposure of
common minerals with cosmic rays is a function of the time that a rock
has been exposed on the earth's surface. This dating can cover a time
span that is undateable by radiocarbon dating and other techniques.