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Sunday, 1 May 2011

Asteroid Impacts in Antarctica? - Testing The Hypothesis

Asteroid Impacts in Antarctica? - Testing The Hypothesis


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.

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