[meteorite-list] New Mars Meteorites (DAG 1037, NWA 2046, SAU 130)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:09 2004
Message-ID: <200404010128.RAA08207_at_zagami.jpl.nasa.gov>

Below is the Meteoritical Bulletin announcing the discovery of
two new Mars meteorites: DAG 1037 and NWA 2046. NWA 2046 was
announced previously by Anthony Irving last January. Also, not
mentioned in the Bulletin is yet another Mars meteorite which
was recovered by Mike Farmer in January 2004:
SAU 130. SAU 130 weighs 116 grams and was found in Oman.
SAU 130 is assumed paired with the other SAU Mars meteorites, which
now includes eight numbered meteorites. So, taking into account
pairings and prior annoucements, DAG 1037 is the only 'new'
Mars meteorite in this group, and bumps up the Mars meteorite
count to 31.


Ron Baalke


                Announcement 88-4, March 31, 2004
            Sara Russell, Editor (sara.russell_at_nhm.ac.uk)
            Mike Zolensky, Assoc. Ed. for Northwest Africa
          Luigi Folco, Assoc. Ed. for Africa (folco_at_unisi.it)
         Monica Grady, Assoc. Ed. for Oman (M.Grady_at_nhm.ac.uk)
       Rhian Jones, Assoc. Ed. for the Americas (rjones_at_unm.edu)
               Kevin Righter, Assoc. Ed. for Antarctica
      Jeffrey N. Grossman, Assoc. Ed. for Web (jgrossman_at_usgs.gov)

This is the fourth electronic announcement of new meteorites to be
published in Meteoritical Bulletin, No. 88, 2004 July.

Martian meteorites:

Dar al Gani 1037 Basaltic shergottite (4.0 kg, Libya)
                         [see below]
Northwest Africa 2046 Basaltic shergottite (63 g, Morocco)
                         [see below]


Dar al Gani 1037 27d20.00' N, 16d13.00' E
   Found 1999
   Martian meteorite (basaltic shergottite)
Ten stones totaling 4012.43 g were found early 1999 in the sand
desert of Dar al Gani. The biggest individual was a complete
individual of 3090 g with perfect orientation and rather fresh
appearance. Classification and mineralogy (A. Greshake and M. Kurz):
an olivine-phyric shergottite with porphyritic texture; large
chemically zoned olivine megacrysts are set into a fine-grained
groundmass composed of pyroxene and maskelynite; minor phases include
chromite, Ti-rich chromite, sulfides, phosphates, and small Fe-rich
olivines; olivine megacrysts often contain melt inclusions and small
chromites; pyroxenes are dominantly chemically zoned pigeonites, some
contain orthopyroxene cores; olivine phenocrysts, Fa31.4-41.1, Fe/Mn

Northwest Africa 2046
   Purchased 2003 September
   Martian meteorite (basaltic shergottite)
A 63g complete and partially crusted stone found near Lakhbi, Algeria
was purchased from a Moroccan dealer in 2003 September by M. Farmer
(Farmer). The ellipsoidal stone has an average width of 30 mm, with
a 1 to 3 mm thick weathering rind; the interior is very fresh and
unweathered. Classification and mineralogy (J. Wittke and T. Bunch,
NAU; A. Irving and S. Kuehner, UWS): olivine-orthopyroxene-phyric
basaltic rock. Subhedral to euhedral, dark brown olivine phenocrysts
(up to 2.2 mm long) are strongly zoned from cores of Fa15.7 to rims
of Fa47.9, and subhedral to euhedral, prismatic orthopyroxene
phenocrysts (up to 2.1 mm long) have cores as magnesian as
Fs17.7Wo2.5, surrounded by irregularly zoned mantles with both
pigeonite and augite, and pigeonite rims as ferroan as Fs39.0Wo12.5.
The groundmass consists mainly of zoned pigeonite (Fs30Wo6.5 to
Fs40Wo13) intergrown with maskelynite (zoned from cores of
Ab25.5Or0.1 to rims of Ab36.5Or1.1) and small grains of relatively
ferroan olivine (Fa47.6-58.1). Accessory minerals include Ti-
chromite (Al/(Al+Cr) = 13.8-28.3), chromite, ilmenite,
Cr-ulvöspinel, pyrrhotite (commonly in parallel growth with
ilmenite), merrillite, rare chlorapatite, and rare fayalite (which
occurs as a reaction rim on groundmass pigeonite in contact with
ilmenite or pyrrhotite). Trapped melt inclusions in olivine contain
aluminous diopside, amphibole(?), pleonaste, chromite, merrillite and
glass. Large, prismatic orthopyroxene phenocrysts exhibit preferred
orientation; olivine phenocrysts are weakly oriented and tend to
occur in clusters. Textures and mineral compositions are similar to
those in olivine-orthopyroxene-phyric shergottite NWA 1195, but the
olivine cores in NWA 2046 are more magnesian (Irving et al., 2004).
Specimens: type specimen, 12.2 g, and one polished thin section, NAU;
one polished thin section, UWS; main mass, Strope.

Received on Wed 31 Mar 2004 08:28:07 PM PST

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