[meteorite-list] Snow and Mars water and meteorites

From: Francis Graham <francisgraham_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:29 2004
Message-ID: <20030221152822.16551.qmail_at_web40109.mail.yahoo.com>

  Mike Reynolds forwarded an interesting article about
Snow pack providing the pressure for Mars water to
exist and form gullies.
  If this is true, since snow (sublimated frost) can
form anywhere on Mars, there ought to be more gullies
in the lower elevations (say, the rim of the Hellas
Basin) than in the higher elevations (Tharsis
plateau), at similar distances from the equator.
This is because the pressure on Mars is near the
Triple Point pressure, and a similar amount of snow in
either place ought to produce more gullies in the
place where the air pressure "helps" most.
  There are some assumptions here, and certainly the
gulley system shows a wide range of ages. One must not
be too hasty in jumping to conclusions, but a
superficial glance does show more larger gullies at
lower elevations. A precise count and control for age
from crater counts may be helpful.
  Further, there should be some variation in the
alteration of same-age Martian meteorites originating
from high elevation on Mars to low elevations. As the
Morroccans busily increase the sample (and
non-Morrocans like Mr Verish :), we will see.

Francis Graham




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Received on Fri 21 Feb 2003 10:28:22 AM PST