[meteorite-list] Prehistoric Meteorite Punched Hole In Earth's Crust

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:42:06 2004
Message-ID: <200101301842.KAA20491_at_zagami.jpl.nasa.gov>

http://www.kcstar.com/item/pages/printer.pat,fyi/37751701.129,.html

Prehistoric meteorite punched hole in crust

By ALEXANDRA WITZE
The Dallas Morning News
January 29, 2001

The meteorite impact that presumably killed the dinosaurs also punched
entirely through Earth's crust, a Texas geologist has found.

It's the first time anyone has documented such a genuinely deep impact, says
Gail Christeson of the University of Texas at Austin.

She and her colleagues have been scrutinizing the 65 million-year-old
Chicxulub crater on Mexico's Yucatan Peninsula. Most scientists think the
crater represents a scar left by a giant meteorite; when it hit it kicked
enough dust into the atmosphere to blot out the sun and cause worldwide
extinctions.

New seismic data, taken from a research vessel cruising off the Yucatan
coast, reveal how profoundly the impact altered the crust, Christeson said
at a recent meeting of the American Geophysical Union. The crater now lies
under water and sediment, and bouncing seismic signals through the ground
can reveal its buried geological structures.

The scientists found that after the impact dug a hole in Earth's crust,
rocks at the center of the crater rose approximately 11 miles to take the
place of the excavated material. The impact even punched 22 miles deep,
where it caused the boundary between Earth's core and its mantel to rise by
about a mile and a half.

An international team of scientists plans to drill a deep hole into the
crater, which they hope will reveal more about the infamous impact.
Received on Tue 30 Jan 2001 01:42:15 PM PST