[meteorite-list] SNC Trapped Gases/Martian Atmosphere
From: Mark Fox <unclefireballmtf_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:24 2004
April 7, 2002
Greetings Meteorite Enthusiasts!
A thought has just occurred to me today. According to
Harry Y. Mcsween, Jr.'s Meteorites and Their Parent
Planets, most Martian meteorites (except ALH84001 for
example) were determined to have significant young
crystallization ages (roughly 1.3 - 0.2 billion years)
as compared to your average chondrite or HED
achondrite (roughly 4.5 billion years). With this in
mind, it was also derived, through a fascinating
discovery, that impact-melted glass in such space
rocks were found to contain trapped gases; interpreted
to represent their parent body's atmosphere --- Mars.
As I understand, this conclusion was originally based
on the information gleaned from the Viking missions.
Also, the similarities between the trapped gases and
the Martian atmosphere were not vague in the least,
but very striking. Hence, this conclusion provided a
monumental push to connect SNCs with the red planet.
However, some questions and comments have emerged:
What were all the different trapped gases observed in
the SNCs and were there any significant differences
noticed in their abundances as compared to the Martian
Also, are there any good clues as to approximately
when most of the SNCs so far studied were blasted off
the Martian surface, or left home as so to speak?
I have gotten the impression from what I have read
that the impacts that brought the Martian rocks to us
occurred quite early in the history of the red planet
(millions to a few billion years ago). If true, what
does that have to say for the striking similarity
between the trapped SNC gases and the Martian
atmosphere? Am I correct in my assumption that the
atmosphere on Mars has remained practically unchanged
all that time, including the presence of oxygen and
carbon dioxide? If so, what factors made it more
likely that life existed on the planet in those early
years than in recent times?
Please forgive me if I have incorrectly quoted any of
the above information or the like. Hope your noodle
Long strewn fields!
Newaygo, MI USA
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Received on Sun 07 Apr 2002 09:06:32 PM PDT