SESSION 48: THE SNOWBALL EARTH HYPOTHESIS: THEORY AND OBSERVATIONS. Thursday, June 28
Abstracts: http://gsa.confex.com/gsa/2001ESP/finalprogram/session_186.htm
Poster Session 56 Abstracts: http://gsa.confex.com/gsa/2001ESP/finalprogram/session_962.htm
Experts in geology, atmospheric science, marine geochemistry, and evolutionary biology will bring a mix of new discoveries and contrasting perspectives on this highly controversial theory of planetary glaciation, where the poles were covered by ice and the oceans were frozen. Paul Hoffman, Department of Earth and Planetary Sciences, Harvard University, will introduce the session and emphasize that any successful hypothesis must account for a unique set of geological observations. During his presentation, he will argue that the Snowball hypothesis does this better than any competing theory, but that a possible conflict with evidence for terrestrial ice streams must be resolved.

Grant M. Young is a senior geologist at the University of Western Ontario with long international experience. Twenty-five years ago, he made the important observation that the glacial deposits of the Paleoproterozoic Gowganda Formation in Canada are overlain by sediments with evidence for intense tropical weathering. The Snowball Earth hypothesis provides one possible explanation for this paradox. However, Young prefers to interpret these unusual rock associations as being due to glaciation under a CO2-rich atmosphere, made possible by weak radiation from the faint young sun, and other radically different conditions of the Earth at that time. He proposes that the Snowball theory is really a "no-ball" theory.

Lee R. Kump, Department of Geosciences at Penn State University, will present an innovative conce
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Contact: Ann Cairns
acairns@geosociety.org
303-447-2020 x 1156
Geological Society of America
24-May-2001