Earth's sediments record a falling sky

May 23, 2008

Boulder, CO, USA - A new publication by The Geological Society of America illustrates the sedimentary record of meteorite impacts on Earth. Senior volume editor Kevin R. Evans of Missouri State University notes that "up until the 1960s, the geologic community largely regarded meteorite impacts as geologic sideshows and curiosities, and inherently controversial. Today, it is widely recognized that large impacts have played a pivotal role in the evolution of Earth's biota and sculpted the surface of the planet."

Large meteorite impacts are agents of sedimentation; sedimentary particles are generated through brecciation, which then are transported, emplaced, and deposited. In addition to the deformation of sedimentary target rocks, the record of meteorite impacts also includes ejecta and tsunami deposits, both of which typically are preserved in sedimentary successions.

"Although the future holds risks of impact," Evans explains, "ancient impact structures may also be viewed as resources, where breccia bodies and peripheral strata host accumulations of hydrocarbons and ore deposits."

Currently, says Evans, "Nearly all known terrestrial meteorite impacts are on continents or continental shelves, but many, including most of the examples detailed in this volume, actually occurred in marine settings." The impact-related structures examined in this book include Chesapeake Bay, Gardnos, Lockne, Mjølnir, and Weaubleau, and distal deposits from the Alamo, Avak, and Chicxulub impacts.
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Individual copies of the volume may be purchased through the Geological Society of America online bookstore http://rock.geosociety.org/Bookstore/default.asp?oID=0&catID=9&pID=SPE437 or by contacting GSA Sales and Service, gsaservice@geosociety.org.

Book editors of earth science journals/publications may request a review copy by contacting Jeanette Hammann, jhammann@geosociety.org.

The Sedimentary Record of Meteorite Impacts
Kevin Evans, J. Wright Horton Jr., David T. King Jr., and Jared R. Morrow (editors)
Geological Society of America Special Paper 437
2008, 213 pages, US$70, GSA member price US$49
ISBN 978-0-8137-2437-9

www.geosociety.org

Geological Society of America

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