[meteorite-list] Lunar/Martian controversy

From: Starbits_at_aol.com <Starbits_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:02 2004
Message-ID: <1c2.132b6a83.2d15d534_at_aol.com>

In a message dated 12/20/2003 8:24:13 AM US Mountain Standard Time,
j.divelbiss_at_att.net writes:

<< Q: When were most space floaters from Mars and the Moon created?
 A: A couple billions of years ago when most of the planetary bombardments
 were occurring. >>

    Actually they are much, much younger. The CRE ages (time floating in
space) for martian meteorites range from 19.8 million years to less than 1
million years with a group at 10-12 million years and most less than 2 million
years. The lunar meteorites are practically instantaneous in comparison.
    So the difference is likely the sampling time frame. If the decay to
being unrecognizable is 50,000 years on earth, then the lunar meteorites are
resulting from significant impacts during that timeframe. The martian sampling
timeframe is about 400 times longer giving much more time for significant
impacts even if they have to be larger impacts. In addition an impact on mars will
continue to drop meteorites for millions of years until they hit a planet,
burn up in the sun, or get tossed out of the solar system. With lunar
meteorites it is a shotgun blast and wait for the next impact.
     The longer time frame for Mars and the smaller impacts necessary for the
moon evidently even things out.

Eric Olson
ELKK Meteorites
http://www.star-bits.com
Received on Sat 20 Dec 2003 11:39:16 AM PST