Published: Feb. 18, 2002

Michael Bender, a Princeton University professor of geosciences and a fellow of the American Geophysical Union, will present a new method of dating ice cores at the University of Colorado at Boulder on Friday, Feb. 22.

Bender will speak at 4 p.m. in the auditorium of the Cooperative Institute for Research in Environmental Sciences, room 338. The talk is free and open to the public. A reception will follow.

Paleoclimatologists study ice cores to learn the history of Earth's climate from sediments and gases trapped in ice core layers. Ice cores hold information about local temperature, precipitation rates, humidity, wind speed and atmospheric composition, and can be measured for a variety of trace gas concentrations, isotopes and aerosols.

The title of Bender's talk is "An Absolute Age Scale for the Vostok Ice Core: Implications for the Role of Milankovitch Forcing of Glacial-Interglacial Climate Change." Milankovitch forcing involves orbital variations by Earth around the sun that affect the distribution of global solar energy, causing climate change.

Ice cores from Vostok, Antarctica, cover multiple glacial and interglacial cycles and are the only ice cores that scientists are certain have remained undisturbed for the last interglacial and the next-to-last glacial periods. Bender will describe a new method to improve the accuracy of dating ice cores and the implications of the new dates for the Vostok core.

The new method, combined with gas measurements from the Vostok ice cores, can help scientists both establish a chronology for the cores as well as understand the relationship between solar activity and climate change, he said.

Bender's talk is presented as part of the Distinguished Lecture Series program sponsored by CIRES. For more information visit the Web site at .