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Release: April 8, 1999

UI presents April 13 lecture on caves and climate change

IOWA CITY, Iowa -- The University of Iowa Museum of Natural History will present a free, public lecture, "Stalagmites, Caves and Climate Change," at 7 p.m. Tuesday, April 13 in Room 112, First Floor, Macbride Hall.

Part of the Museum's "Afternoon With a Scientist" lecture series, the talk will be given by Rhawn Denniston, UI doctoral candidate who has worked on a new method of reconstructing ancient climates for three and one-half years under the supervision of Luis Gonzalez, UI associate professor of geology. Specifically, he and Gonzalez measure the ratio of carbon and oxygen isotopes in stalagmites and other cave rock formations. According to Denniston, the annual layers that make up stalagmites can be precisely dated and offer an alternative to pollen, sometimes preserved in lakes and ponds, and animal fossils.

Denniston, who has used stalagmites to date the advance and retreat of Midwest prairies and measure rainfall amounts during Nepal's monsoon season, will also exhibit stalagmite specimens and show slides highlighting his work in Iowa, Missouri and Nepal.

For more information, call David Brenzel, program coordinator, at 335-0482.