[meteorite-list] nwa869

From: almitt <almitt_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:05 2004
Message-ID: <3D276A17.3FB146D0_at_kconline.com>

Hi John and all,

Many of the parent bodies have yet to be identify to the many of the meteorites we
have accumulated here on Earth. However there are some suspect parent bodies which
have been identified by spectral matches to the asteroids and meteorites. One such
match is asteroid Hebe for the H type chondrites. It is obvious from looking at Hebe's
surface that it has a variation in spectra as the asteroid rotates representing the
different metamorphism (classes) we see from the change in olivine to pyroxene ratio.
No doubt the asteroid had a large enough impact at one time to knock it apart allowing
the more differentiated classes to show up on the outside, and some of the outer part
of the asteroid became buried in the interior as it reassembled into a rubble pile
asteroid. It isn't uncommon for H type chondrites to have brecciation of various
different classes all in one meteorite. A good example of this is Zag (H3-6) and
Noblesville, Indiana an H4 chondrite with H6 clasts. Probably why we get so many of
the H type chondrite material now is we are living at a time when the results of the
impacts which have been migrating to us over the eons have finally made their way to
fall at a constant rate. If we lived in a different time many years from now or very
long ago then perhaps and most likely we would sample some other type of meteorite
falls. Perhaps it wouldn't be uncommon for some rare type meteorite (to us) to fall at
a regular more consistent rate.

How does this tie into NWA 869. As stated earlier we don't know all of the parent
bodies yet (a good reason for funding to NASA to build a craft to visit as many
asteroids as we can) However there is one asteroid of about 7 km in diameter that
resides in the main belt and may be related to the L type chondrites and a possible
parent body though a very weak link. Asteroid 3628 Boznemcova exhibits spectral
qualities to the L's and LL's. It is obviously too small to be a complete asteroid and
has been suggested it is a fragment of a much larger asteroid. Perhaps this might be
what is left of the NWA 869 and other L type meteorites and why we sample a steady
rate of L type chondrites.

Beside these parent bodies, we are fairly sure of the Vesta and HED type meteorite
connections as well as the Martian (SNC), and lunar meteorite to Moon connections.
It's what makes reading about and research on meteorites so exciting and trying to
figure out all of the complicated puzzles they present to us.

--AL Mitterling
Received on Sat 06 Jul 2002 06:07:19 PM PDT