[meteorite-list] Satellite Reveals Large Impact Craters Across Antarctica

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Aug 19 12:10:38 2004
Message-ID: <200408191610.JAA16991_at_zagami.jpl.nasa.gov>

http://thescotsman.scotsman.com/international.cfm?id=959452004

Satellite reveals the biggest of big bangs
JAMES REYNOLDS
The Scotsman (Scotland)
August 19, 2004

SCIENTISTS have discovered the largest area on Earth ever to have been
struck by a storm of meteorites.

Using satellite technology to observe the Antarctic gravity field from
thousands of miles above the earth, the international team of
geophysicists found evidence of many large meteorite impact sites across
the entire continent.

Presenting their research to the International Geographical Congress in
Glasgow yesterday, the results of the imaging revealed that the sites
extend from the Ross Sea in the vicinity of the Pacific Ocean, to the
Weddell Sea south of the Atlantic Ocean.

However, those wishing to make a journey to Antarctica to see for
themselves the craters left by the interstellar objects will be
disappointed. Lying beneath the East Antarctic continental ice sheet,
most of the sites are not visible because they are shielded by hundreds
of millions of tons of ice.

However, offshore in the Ross and Weddell Seas impact craters can be
viewed on the seabed.

The area where the meteorites struck - known as scatter ellipses - is
the largest so far found on Earth. It measures some 1,300 by 2,400
miles, according to the researchers.

A meteorite crater in Victoria Land, Antarctica, was discovered in the
1970s by the United States Antarctic Research Programme. The site was
found after changes to the gravity below the ice were observed - a sign
of the mass of rock blasted from the crater when the meteorite crashed
and exploded, killing every living thing for hundreds of miles around.

The new discovery of a scatter ellipse shows a much greater apparent
impact event than previously known.

It is not yet clear when the meteorites hit Earth or their origins. They
may have come from an asteroid belt which is located roughly 484 million
miles from Earth.

Alternatively, they may have been swarms of comets or comet fragments
from the solar system's very distant Oort Cloud, 7,000 trillion miles
from Earth, said Dr Frans van der Hoeven, of Delft University of
Technology, in the Netherlands, who led the research.

The scientists estimate that the meteorite impacts could have disrupted
the continental ice sheet, capable of creating ice flows into the
adjoining ocean. This could have raised sea levels worldwide, with
increases ranging anywhere from a few feet to more than 100ft.

The world's most famous meteorite impact crater, the Barringer Meteorite
Crater, is a gigantic hole in the middle of the arid sandstone of the
Arizona desert in the US.

A rim of smashed and jumbled boulders, some of them the size of small
houses, rises 150ft above the level of the surrounding plain. The crater
itself is nearly a mile wide and 570ft deep.

When Europeans first discovered the crater, the plain around it was
covered with chunks of meteoritic iron - more than 30 tons of it.
Received on Thu 19 Aug 2004 12:10:34 PM PDT