[meteorite-list] Meteorite Evidence of an Earth-Moon-Mars Family
From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Fri, 5 Sep 2008 14:43:30 -0500
It's been a long held belief that all the planets reflect
and share the composition of the solar nebula and of
the meteorites that derive from it. A new paper suggests
that idea may be fundamentally wrong.
A study of the crustal composition of the Earth, Mars,
and the Moon, (all but the Earth being sampled by the
meteorites being knocked off them, of course) reveals
that the samarium neodymium isotopic ratios of these
bodies are different from those of meteorites from the
Zone, using meteorites from Vesta, chosen because
it's the largest body in the Zone from which we have
Samarium 147 and samarium 146 decay in the daughter
isotopes neodymium 143 and neodymium 142. The
elements are lithophiles or rock-lovers, so they remain
in the crust. The difference is that the "Earth Family"
has 5% to 8% greater concentrations. This enrichment
is consistent among the "Earth Family" members, large
enough to be significant.
This implies, first, that there IS an "Earth Family"
and, secondly, that all of the "Earth Family" formed from
the same primordial material and that material was not the
same as the rest of the primordial material from which the
rest of the solar system formed. The enrichment is so great
that it had to have happened... Oh, heck, read the articles:
Now, if we had a sample of Venus...
Sterling K. Webb
Received on Fri 05 Sep 2008 03:43:30 PM PDT