[meteorite-list] Asteroid Impacts in Antarctica? - Testing The Hypothesis

From: Paul H. <oxytropidoceras_at_meteoritecentral.com>
Date: Sat, 30 Apr 2011 11:22:04 -0500
Message-ID: <20110430122204.B8HAF.259423.imail_at_eastrmwml29>

In "Asteroid Impacts in Antarctica?"
http://six.pairlist.net/pipermail/meteorite-list/2011-April/076119.html
Ron wrote:

" http://www.cosmosmagazine.com/features/online/4267/asteroid-impacts-antarctica

Asteroid impacts in Antarctica
by Richard A. Lovett
COSMOS Magazine
28 April 2011"

In the article, it is written,

"When did the impact occur? "That's a tricky question,"
Weihaupt says. A definitive answer would require
drilling all the way through the ice to the underlying
rocks."

For the sub-ice anomalies, there is a somewhat less
expensive preliminary step that can be taken towards
testing this hypothesis. Because the Antarctic ice sheet has
been eroding the location of the hypothetical impact craters
for a considerable period of time, a significant amount of
material forming them should have been eroded, entrained,
carried "down glacier," and deposited either in glacial
moraines or as dropstones on the sea floor. Given that the
flow patterns of the ice sheets are now very well known, it
would quite easy to predict where material eroded from
these hypothetical impact craters would have eventually
been deposited either in subaerial glacial moraines or as
dropstones on the ocean floor and where to go looking for
them. This approach for invetsigating the geology of parts
of Antarctica buried by ice sheets is discussed in detail in
"Chapter 11 Geology of Ice-Catchment Provinces in Relation
to Petrography and Mineralogy of Bottom Sediments
Possible Reconstructions of Geological Composition of
Ice-Hidden land" of:

Lisitzin, A. P., 2002, Sea-Ice and Iceberg Sedimentation in
the Ocean: Past and Present. Springer-Verlag, New York,
ISBN 3-540-67965-0

The paper discussed in the Cosmos article is:

Weihaupt, J. G., A. Rice, and F. G. Van der Hoeven, 2010,
Gravity anomalies of the Antarctic lithosphere. Lithosphere.
vol. 2, no. 6, pp. 454-461; DOI: 10.1130/L116.1
http://lithosphere.geoscienceworld.org/cgi/content/abstract/2/6/454
http://lithosphere.geoscienceworld.org/content/vol2/issue6/
http://lithosphere.gsapubs.org/content/2/6/454.abstract?sid=090

Yours,

Paul H.
Received on Sat 30 Apr 2011 12:22:04 PM PDT