[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> This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C398FE.844B6B9A Content-Type: text/plain; charset="iso-8859-1" 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 ------_=_NextPart_001_01C398FE.844B6B9A Content-Type: text/html; charset="iso-8859-1" <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META content="MSHTML 5.00.3809.1800" name=GENERATOR></HEAD> <BODY> <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> </DIV> <DIV><SPAN class=338153000-23102003>If you search the archives, you'll find that we've discussed the Mercury & Venus</SPAN></DIV> <DIV><SPAN class=338153000-23102003>meteorite transfer issue before. 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 earth through very energetic</SPAN></DIV> <DIV><SPAN class=338153000-23102003>impacts. A list member posted results of a computer simulation of transfer statistics</SPAN></DIV> <DIV><SPAN class=338153000-23102003>(e.g. Mars to Earth, Earth to Mars, Moon to Earth, Venus to Earth, and Mercury</SPAN></DIV> <DIV><SPAN class=338153000-23102003>to Earth). I'll try to find the specific post. I recall that the </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. (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> </DIV> <DIV><SPAN class=338153000-23102003>The problem, as you've pointed out, is recognition. 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). E-chondrites would fit the</SPAN></DIV> <DIV><SPAN class=338153000-23102003>bill, but frankly there are too many of them. 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> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=338153000-23102003>--Rob</SPAN></FONT></DIV></BODY></HTML> ------_=_NextPart_001_01C398FE.844B6B9A-- Received on Wed 22 Oct 2003 08:42:20 PM PDT |
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