There's a great story in the Green Valley News on climate research by University of Arizona grad student Sarah Truebe in the Cave of the Bells in the Santa Rita Mountains south of Tucson. She is age dating layers in speleotherms in the cave to reconstruct rainfall rates over the last 5,000 - 7,000 years and tie them to ancient monsoons.
[right, Sarah Truebe, a geosciences doctoral student at the University of Arizona, checks on an experiment that measures how fast cave formations grow in Arizona's Cave of the Bells. Credit: Copyright 2010 Stella Cousins, UA]