[meteorite-list] Meteorites from Venus/Mercury

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:34 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C86901B4EE75_at_US-Torrance.mail.saic.com>

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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

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<DIV><SPAN class=338153000-23102003>Hi Howar</SPAN><SPAN
class=338153000-23102003><FONT color=#0000ff face=Arial size=2><FONT
color=#000000 face="Times New Roman" size=3>d and
List,</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=338153000-23102003></SPAN>&nbsp;</DIV>
<DIV><SPAN class=338153000-23102003>If you search the archives, you'll find that
we've discussed the Mercury&nbsp;&amp; Venus</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>meteorite transfer issue before.&nbsp; I
believe the scientific consensus is that it is indeed</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>possible for both planets to have
transferred material to&nbsp;earth through very energetic</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>impacts.&nbsp; A list member posted results
of a computer&nbsp;simulation of transfer statistics</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>(e.g. Mars to Earth, Earth to
Mars,&nbsp;Moon to Earth,&nbsp;Venus to Earth, and Mercury</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>to&nbsp;Earth).&nbsp; I'll try to find the
specific post.&nbsp; I recall that the&nbsp;</SPAN><SPAN
class=338153000-23102003>mass transfer rate for</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>Mercury was something like a few % of what
it is for Mars, and thus there </SPAN><SPAN class=338153000-23102003>is
a</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>real chance that a Mercury meteorite or two
are hiding amongst our recovered</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>finds.&nbsp; (Don't recall what the transfer
rate was for Venus -- perhaps a bit worse</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>owing to the thick atmosphere.)</SPAN></DIV>
<DIV><SPAN class=338153000-23102003></SPAN>&nbsp;</DIV>
<DIV><SPAN class=338153000-23102003>The problem, as you've pointed out, is
recognition.&nbsp; You'd expect the nickel/iron</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>to </SPAN><SPAN class=338153000-23102003>be
almost entirely in a reduced state (no oxygen).&nbsp; E-chondrites would fit
the</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>bill, but frankly there are too many of
them.&nbsp; I guess one question for the planetary</SPAN></DIV>
<DIV><SPAN class=338153000-23102003>geologists is, "How should Venusian basalt
differ from Martian basalt?"</SPAN></DIV>
<DIV><SPAN class=338153000-23102003></SPAN>&nbsp;</DIV>
<DIV><FONT color=#0000ff face=Arial size=2><SPAN
class=338153000-23102003>--Rob</SPAN></FONT></DIV></BODY></HTML>

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Received on Wed 22 Oct 2003 08:42:20 PM PDT


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