The kinetic energy created by asteroid and comet impacts with the Earth may be key to linking some impacts with mass extinction events. Michael Lucas, a geology student at Florida Gulf Coast University, believes that the severity of four extinction events during the Mesozoic and Cenozoic can be correlated with the total kinetic energy released by impacts that occur during the geologic age of the mass extinction.
Lucas will present his findings April 4 at the Geological Society of Americas North-Central Section and Southeastern Section Joint Meeting in Lexington, Kentucky.
Lucas analyzed the kinetic energy released by 31 of the largest impact structures from the last 248 million years and correlated them with the Norian, Tithonian, Late Eocene, and K-T extinction events. The impact energy released during the geologic ages of each extinction event is at least 10 million megatons of TNT equivalent yield per geologic age. Lucas believes that this could represent a minimum impact energy required to cause a global-scale mass extinction. His research results also reveal that synchronous multiple impact events could also have caused extinctions.
Approximately ten percent of the impact structures on Earth are doublets or twin structures, suggesting a nearly simultaneous impact of binary asteroids or fragmented comets, he said. An example of a twin impact structure would be the Kara / Ust-Kara twin impact structure in Russia which is about 73 million years old.
By Kara LeBeau, GSA Staff Writer
Contact information:
Michael P. Lucas
College of Arts & Sciences
Florida Gulf Coast University
10501 FGCU Blvd. South
Ft. Myers FL 33965 USA
E-mail: mlucas@fgcu.edu
Phone: 941-590-7225
Abstract available at:
http://gsa.confex.com/gsa/2002NC/finalprogram/abstract_3
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Contact: Ann Cairns
acairns@geosociety.org
303-357-1056
Geological Society of America
3-Apr-2002