[meteorite-list] Mercury Meteorites - the short list
From: cdtucson at cox.net <cdtucson_at_meteoritecentral.com>
Date: Sun, 7 Aug 2011 0:32:05 -0400
The very latest info on Mercuries composition does not even mention Fe or FeO. It seems to me if it was there NASA would have already mentioned it.
Mercury's Surface Composition
The X-ray Spectrometer (XRS) ? one of two instruments on MESSENGER designed to measure the abundances of many key elements on Mercury ? has made several important discoveries since the orbital mission began. The magnesium/silicon, aluminum/silicon, and calcium/silicon ratios averaged over large areas of the planet's surface show that, unlike the surface of the Moon, Mercury's surface is not dominated by feldspar-rich rocks.
XRS observations have also revealed substantial amounts of sulfur at Mercury's surface, lending support to prior suggestions from ground-based telescopic spectral observations that sulfide minerals are present. This discovery suggests that the original building blocks from which Mercury was assembled may have been less oxidized than those that formed the other terrestrial planets, and it has potentially important implications for understanding the nature of volcanism on Mercury.
So, until the next report it seems all of these older theories might be out the window.
-- "Democracy is two wolves and a lamb voting on what to have for dinner. Liberty is a well-armed lamb contesting the vote". ---- "Bernd V. Pauli" <bernd.pauli at paulinet.de> wrote: > Hi All, > > I would like to remind you of Russ Kempton's article in "Meteorite!" > > Kempton R. (1996) Abee: More Questions Than Answers > (METEORITE! Magazine, Pallasite Press, November, 1996): > > "Curiously, the study of light reflected from Mercury's surface > indicates that it is iron-rich and oxygen-poor - characteristics > shared with E chondrites".* > > ... or with some of their achondritic counterparts: the aubrites. > > * In 1998, our late Richard Norton wrote in RFS: > > "Their low oxygen content suggests that they formed even closer > to the Sun than the H-chondrites, possibly inside Mercury's orbit." > > NORTON O.R. (1998) Rocks From Space, p. 190, E-Chondrites: > > But Mercury's mean density of about 5.4 g/cm^3 is a major problem > because enstatite chondrites have a density of about 3.4-3.7 g/cm^3. > > NWA 011 is also mentioned in the "short list" but here's another obstacle: > > ...its high FeO content, a circumstance which implies a parent body with > a small metallic iron core. Mercury is believed to have a large iron core. > > Niquist et al. (2003) suggest that NWA 011 is of asteroidal rather than > Mercurian origin. > > Love S.G. et al. (1995) think it highly likely that there are Mercurian > meteorites in our collections although they should be rare (probably > less than 1% of the amount of Martian meteorites in our collections)*. > > *Love S.G. et al. (1995) Recognizing mercurian > meteorites (MAPS 30-3, 1995, pp. 269-278). > > Best wishes from rainy > Southern Germany, > > Bernd > > > ______________________________________________ > Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list at meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-listReceived on Sun 07 Aug 2011 12:32:05 AM PDT