[meteorite-list] Sedimentary Rocks As Martian Meteorites??

From: Paul <lenticulina1_at_meteoritecentral.com>
Date: Thu Apr 22 10:27:52 2004
Message-ID: <20031122200343.76273.qmail_at_web21403.mail.yahoo.com>

The below research is interesting in that,
if sedimentary deposits have accumulated in
various parts of Mars, some of them might have
become lithified enough to survived being
blasted off it by meteorite impacts. As a
result, Martian meteorites quite different
from the igneous rocks normally recognized
as meteorites might possibly exist.

Yours,

Paul
Baton Rouge, LA

"Distributary Fan: "Smoking Gun" Evidence for
Persistent Water Flow and Sediment Deposition
on Ancient Mars" MGS MOC Release No. MOC2-543,
13 November 2003

http://www.msss.com/mars_images/moc/2003/11/13/

"This week, the journal Science has published
online (in Science Express) the most recent MOC
discovery: an ancient, eroded, and exhumed
sedimentary distributary fan located in a
crater at 24.3°S, 33.5°W. A distributary fan
is a generic term used by geologists to
describe a family of deposits that includes
river deltas and alluvial fans. Sometime
in the distant past, when it was still
possible for liquid water to flow across the
martian surface, sediments transported through
valleys by water formed a fan-shaped deposit in a
64-kilometer (40 miles) -diameter crater
northeast of Holden Crater.

What is important about this discovery? First,
it provides clear, unequivocal evidence that
some valleys on Mars experienced the same type
of on-going, or, persistent, flow over long
periods of time as rivers do on Earth. Second,
because the fan is today a deposit of
sedimentary rock, it demonstrates that some
sedimentary rocks on Mars were, as has been
suspected but never clearly demonstrated,
deposited in a liquid (probably water)
environment. Third, the general shape,
pattern of its channels, and low topographic
slopes provide circumstantial evidence that
the feature was actually a delta--that is,
a deposit made when a river or stream enters
a body of water. In other words, the landform
discovered by MOC may be the strongest
indicator yet that some craters and other
depressions on Mars once held lakes."

and

Malin, M. C., and Edgett, K. S., 2003, Evidence
for Persistent Flow and Aqueous Sedimentation on
Early Mars

http://www.sciencemag.org/cgi/content/abstract/1090544v1

Published online November 13, 2003
Submitted on August 18, 2003
Accepted on October 28, 2003

Yours,

Paul
Baton Rouge, LA



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Received on Sat 22 Nov 2003 03:03:43 PM PST