Caves and Climate	Volume 55 Number 1, January/February 2002
by Eric A. Powell

Calcite bands in stalagmites are helping archaeologists study climate patterns. (Victor Polyak) [LARGER IMAGE]

Evidence from an unlikely source, stalagmites in Carlsbad Caverns, shows that climate change coincided with major cultural innovations in the prehistoric Southwest. Victor Polyak and Yemane Asmerom of the University of New Mexico measured the thickness of calcite bands in stalagmites to create an annual record of precipitation in the region going back almost 4,000 years.

They found their climate data closely corresponded to the archaeological record. "There really seemed to be a close correlation, it was eerie," says Asmerom. Thick calcite bands indicated a wet period beginning around 1000 B.C., which coincides with the rise of corn agriculture in the region ("To Farm, or Not To Farm," September/October 1998). Thinner bands suggested a drier period beginning in A.D. 300, corresponding to the introduction of ceramics. The calcite bands thicken at A.D. 750, the same time the archaeological record shows a population expansion in the region. "It's fascinating," says University of New Mexico archaeologist Robert Leonard, who is familiar with the work. "I never dreamed that you could do this with stalagmites. There are quite a few caves in the Southwest. A lot more work could be done."

© 2002 by the Archaeological Institute of America archive.archaeology.org/0201/newsbriefs/caves.html