[meteorite-list] Largest Ever Field of Impact Craters Uncovered in Egypt

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Nov 4 12:17:52 2004
Message-ID: <200411041717.JAA01245_at_zagami.jpl.nasa.gov>

http://www.newscientist.com/news/news.jsp?id=ns99996611

Largest ever field of impact craters uncovered
Jonathan Walker
New Scientist
November 3, 2004
 
The discovery of the largest field of impact craters ever uncovered on
Earth is the first evidence that the planet suffered simultaneous meteor
impacts in the recent past. The field has gone unnoticed until now
because it is partially buried beneath the sands of the Sahara desert in
south-west Egypt.

Philippe Paillou of Bordeaux University Observatory in Floirac, France,
first noticed circular geological structures in the Sahara last year,
while analysing radar satellite pictures of the area.

The structures turned out to be part of a huge field of 100 craters
spread over 5000 square kilometres near the Gilf Kebir plateau. The
craters vary in diameter from 20 metres to 2 kilometres across. The
previous largest known crater field covers a mere 60 square kilometres
in Argentina.

In February, Paillou led a joint Egyptian and French mission to find the
site and examined 13 of the craters, confirming that they were the
result of simultaneous impacts. But accurately dating the field has been
tricky. Paillou estimates that it is roughly 50 million years old,
relatively young in geological terms.

The size of the field suggests that it could be the result of two or
more meteors disintegrating as they entered Earth???s atmosphere, the
first evidence of a multiple strike, he says.

"Because the field is so big, it can't have been made by one meteor,"
says Paillou. But more information is needed to understand the event and
its effects, and Paillou plans to return to the area next month.
Received on Thu 04 Nov 2004 12:17:43 PM PST