Chicxulub Impact Event

(Just how big is it?)

Justin Soberaski

Approximately 65million years ago, a stony meteorite (10-15 km in diameter) punched through a region of a 3-km thick carbonate platform overlying a granitic basement. The impact occurred near the present day village of Chicxulub, located in the Northern part of the Yucatan Peninsula.

GRAPHIC BY MIAC, WEB SOURCE

RECREATION OF CHICXULUB METEORITE

The gigantic wound inflicted on the rocks underneath Chicxulub received from the meteorite is also associated with the demise of the dinosaurs. It is widely accepted that the Chicxulub impact is the event that ended the Cretaceous Era.

The exact morphology and size of the crater is under fire by scientists. The Chicxulub impact, which is buried under a km of post impact sediments in its center doesn’t outcrop any where at the surface. This makes it difficult and highly disputable by scientists deciphering the data from seismic information, gravity anomalies, and well logs.

GRAPHIC BY JAY MELOSH, NATURE, DEC 27, 2001

MORPHOLOGY OF CRATER

The size of the crater (outer ring), which is currently being disputed by physicists and geologists ranges from 180 km to 300km in diameter. The destruction of the impact known globally is not fully understood, but with further understanding of the size of the crater scientists can make clearer hypotheses to the magnitude of it.

References

Alvarez, Walter. Philippe, Casey. 1995, Emplacement of Cretaceous- Tertiary boundary shocked quartz from Chicxulub crater. Science. v 269: n5226 pg 903-909. August 18.

Brit, R,. Robert. 2002, Planet Earth. Space. Com web page,

http://www.space.com/scienceastronomy/planetearth/asteriod_jello_001122.html

Heinrich, Bahlburg, Geologisch-Palaontologisches Institut. web page.

http://www.uni-muenter.de/GeoPalaeontologie/Geologie/Sedi/Research/six/six.htm

Hildebrand, Alan. Geological Society of Canada. Chicxulub Crater, Mexico, and the Cretaceous-Tertitaryboundary.Webpage. http://wwwdsa.uqac.uquebec.ca/mhiggins/MICA/chicxulub.htm

Melosh, Jay. 2001, Geophysics: Deep down at Chicxulub. Nature. News and Views, pg 861-862, Dec 27.

Melosh, Jay. 1997, Multi-Ringed Revelation. Nature. News and Views, pg 439-440, vol 390. Dec 4.

Monastersky, Richard. 1997, Getting to the core of a killer crater, Science News, v152, n24, pg 379, Dec 13.

Morgan, Jo. Warner, Mike. 1997, Size and Morphology of the Chicxulub Impact Crater, Nature, Vol 390, Dec.

Pope, O., Kevin. 2002, Impact Dust not the cause of the Cretaceous – Tertiary mass extinction. Geological Society of America, v 30: pg.99-102.

Schuraytz, C,. Benjamin. Lindstrom J., David. 1996, Iridium metal in Chicxulub impact melt: forensic chemistry, Science, v271: pg. 1573-1579, March 15.

Sharpton, L., Vigil. Burke, Kevin. 1993, Chicxulub Multiring Impact Basin: Size and other Characteristics derived from Gravity Analysis, Science, v261 n5128, pg 1564-1568, Sept 17.

Swisher, C,.Carl. Grajales-Nishimura, M,. Jose. 1992, Coeval 40Ar/39Ar of 65.0 million yrs ago from Chicxulub crater melt rocks, Science, v257: n5072 pg 945-950. August 14.