• Alfred McEwen: Principal Investigator, High Resolution Imaging Science Experiment (HiRISE) camera, Mars Reconnaissance Orbiter, and Professor of Planetary Sciences, University of Arizona, Tucson, Arizona, USA;
• Steven W. Squyres: Principal Investigator, Mars Exploration Rover mission, and Goldwin Smith Professor of Astronomy, Cornell University, Ithaca, New York, USA;
• Albert S. Yen: Mars Exploration Rover science team member, NASA Jet Propulsion Laboratory, Pasadena, California, USA.

Session: P32A

Wednesday, 23 May
1000h

Ancient Debris Suggests Deadly, Climate-changing Blast

Investigations of a buried layer at sites from California to Belgium reveal materials that include metallic microspherules, carbon spherules, nanodiamonds, fullerenes, charcoal, and soot. The layer's composition may indicate that a massive body, possibly a comet, exploded in the atmosphere over the Laurentide Ice Sheet 12,900 years ago. The timing coincides with a great die-off of mammoths and other North American megafauna and the onset of a period of cooling in Northern Europe and elswhere known as the Younger Dryas Event. Speakers will discuss numerous lines of evidence contributing to the impact hypothesis. The nature and frequency of this new kind of impact event could have major implications for our understanding of extinctions and climate change.

Participants

• Richard Firestone : Staff Scientist, Lawrence Berkeley National Laboratory, Berkeley, California, USA;
• James Kennett: Professor, Dept. of Earth Sciences, University of California, Santa Barbara, California, USA;
• Allen West: Geoscience Consulting, Dewey, Arizona, USA;
• Luann Becker: Associate Researcher, Institute for Crustal Studies, University of California, Santa Barbara, California, USA.

Session: PP41A

Wednesday, 23 May
1400h

Challenges to Water
'"/>

Contact: Peter Weiss
pweiss@agu.org
202-777-7507
American Geophysical Union
18-May-2007