Hi Howard and
List,
If you search the archives, you'll find that
we've discussed the Mercury & Venus
meteorite transfer issue before. I
believe the scientific consensus is that it is indeed
possible for both planets to have
transferred material to earth through very energetic
impacts. A list member posted results
of a computer simulation of transfer statistics
(e.g. Mars to Earth, Earth to
Mars, Moon to Earth, Venus to Earth, and Mercury
to Earth). I'll try to find the
specific post. I recall that the mass transfer rate for
Mercury was something like a few % of what
it is for Mars, and thus there is
a
real chance that a Mercury meteorite or two
are hiding amongst our recovered
finds. (Don't recall what the transfer
rate was for Venus -- perhaps a bit worse
owing to the thick atmosphere.)
The problem, as you've pointed out, is
recognition. You'd expect the nickel/iron
to be
almost entirely in a reduced state (no oxygen). E-chondrites would fit
the
bill, but frankly there are too many of
them. I guess one question for the planetary
geologists is, "How should Venusian basalt
differ from Martian basalt?"
--Rob
