University of Alaska Geologist
Studies Chicxulub Impact Crater
January 19, 2007
Friday
About 65 million years ago, a massive disruption led to worldwide
extinction of dinosaurs. The impact of a giant asteroid created
massive tsunamis and spewed forth a global cloud of carbon gases
that altered Earth's atmosphere and blocked the light for weeks,
possibly years. In recent years, that impact event has been linked
to a 112-mile-wide crater, dubbed Chicxulub, on the coast of
Mexico's Yucatan Peninsula.
Shaded relief image
of the Yucatan Peninsula generated with data from the Space Shuttle
Radar Topography Mission. Image also illustrates the location
of the Yaxopoil-1 (Yax-1) well and other subsurface drill cores,
and crater ring locations based on gravity data (Sharpton et
al., 1193). 2005 seismic lines are illustrated in red while pre-2005
lines are indicated by dashed black lines. Radar image courtesy
NASA
http://photojournal.jpl.nasa.gov/catalog/PIA03379
Since its discovery in the 1980s, the Chicxulub crater has left
its own impact on sky-watchers and sci-fi fans worldwide, and
impact events have been depicted in Hollywood films such as "Armageddon"
and "Deep Impact," as well as countless artistic renditions.
Despite the spotlight on the theories surrounding the impact,
Michael Whalen, associate professor of geology at University
of Alaska Fairbanks, has managed to stay "out of the limelight,
yet into the limestone" with his work sampling the core
of the crater. Due to the efforts of Dr. Buck Sharpton, UAF Vice
Chancellor for Research, Whalen became part of an international
effort to correlate seismic data with information obtained from
a drill hole that reaches more than 1.2 miles deep, through the
impact layer and beyond.
Interestingly enough, unlike other more noticeable craters, the
Chicxulub crater spent 55 million years in virtual obscurity,
due to the fast infilling that masked its presence. Speedy recovery,
which by geologists' standards amounts to about 10 million years,
preserved the crater by mantling it with sediment, attracting
geologists like Whalen, who studies the effects of extinction
events on carbonate layers (also known as limestone) and the
organisms that make up those layers.
On Jan. 20th, Whalen will be traveling with a team to the Chicxulub
site for a week to obtain more core samples in order to get a
better understanding of how the crater filled in and how the
earth itself recovered from the massive impact. He's also part
of an ongoing collaboration that is trying to secure funding
to drill two more holes in the crater, one off shore and one
through the peak ring.
Source of News & Graphic:
Geophysical Institute - University
of Alaska Fairbanks
www.gi.alaska.edu
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