Hi, All --
Water on Mars is nothing new, despite the frantic
pronoucements nearly every week.
The nakhlite meteorites all (?) contain veinlets of clay and
other water-bearing minerals that formed before the meteorites
arrived on Earth. The veinlets are pre-terrestrial because they
are cut off by, and melted at, the meteorites' fusion crusts.
Unless they formed in interplanetary space, the clays came from
the parent planet, Mars.
Mineralogically, the veinlets are not unusual - clays, probably
goethite (FeOOH), and ferrihydrite (a ferric oxide hydrate). You'd
find the same stuff in a rusty rock on Earth.
The martian origin of these clay veinlets was documented first in
1991 for Nakhla
Gooding J.L., Wentworth S.J., and Zolensky M.E. (1991) Aqueous alteration of
the Nakhla meteorite. Meteoritics 26, 135-143.
in 1993 for Lafayette
Treiman A.H., Barrett R.A. and Gooding J.L. (1993) Preterrestrial aqueous
alteration of the Lafayette (SNC) meteorite. Meteoritics 28, 86-97.
and last year for NWA817
Gillet Ph., Barrat J.A., Crozaz G., Deloule E., Jambon A., Neuville D.,
Sautter V., and Wadhwa M. (2001) Aqueous alteration in the NWA817 martian
meteorite. Meteorit. Planet. Sci. 36, A66, (abstr. #5117).
The clay material is pretty young in martian terms,
it formed ~ 700 million years ago.
Swindle T.D., Treiman A.H., Lindstrom D.J., Burkland M.K., Cohen B.A., Grier
J.A., Li B., and Olson E.K. (2000) Noble gases in iddingsite from the
Lafayette meteorite: Evidence for liquid water on Mars in the last few
hundred million years. Meteor. Planet. Sci. 35, 107-116.
Yours,
Allan
Allan H. Treiman
Lunar and Planetary Institute
3600 Bay Area Boulevard
Houston TX 77058-1113
281-486-2117
281-486-2162 FAX
[EMAIL PROTECTED]
-----Original Message-----
From: Michael Blood [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 10, 2002 4:52 AM
To: Ron Baalke
Cc: Meteorite Mailing List
Subject: [meteorite-list] Unique Martian Meteorites Found In Africa (NWA
998 and NWA 1195)
Hi Ron & Michael,
OK, guys, I'm not a chemest nor do I have a degree
(or even classes in) solar system petrology - and therein
squats the toad.......but this NWA 998 sounds like it PROVES
there was water on Mars. Am I right on this?
Also, the NWA 998 looks a hell of a lot fresher than the
NWA 1195 - and sounds SOMEHOW more compelling - but
the 1195 ALSO indicates Martian water...right?
Please help us less educated fellows out, here. Can one
of you explain this in language a reasonably inteligent
person but who is not educated in chemestry/petrology type
stuff can grok?
RSVP
Thanks, Michael
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