[meteorite-list] New Mars Meteorite Descriptions From Meteoritical Bulletin Annoucement 86-1

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:23 2004
Message-ID: <200204052021.MAA07616_at_zagami.jpl.nasa.gov>

Below are excerpts from a Meteoritical Bulletin announcement sent out today
on seven recent Mars meteorites finds. Of these
Mars meteorites, SAU 060 and SAU 090 are new. Since these two
Mars meteorite were found near the other four SAU Mars meteorites and are
also basaltic shergottites, they are assumed to be paired with this group.
Taking into account pairings, the number of Mars meteorites remains at 24.

Ron Baalke

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                    THE METEORITICAL BULLETIN
                 Announcement 86-1, April 5, 2002
               Sara Russell, Editor (sara.russell_at_nhm.ac.uk)
          Jutta Zipfel, Assoc. Ed. for Saharan Meteorites
                  (zipfel_at_mpch-mainz.mpg.de)
    Jeffrey N. Grossman, Assoc. Ed. for Web (jgrossman_at_usgs.gov)
                 Monica M. Grady, Co-Editor

Announcements of new meteorites
to be published in Meteoritical Bulletin, No. 86, 2002 July. Here,
you will find the complete text of announcements of Martian meteorites
described in the past year.

Marian meteorites described below:

Dhofar 378 Basaltic shergottite (Oman)
Grove Mountains 99027 Lherzolitic shergottite (Antarctica)
Northwest Africa 856 Basaltic shergottite (Africa*)
Northwest Africa 1068 Basaltic shergottite (Africa*)
Northwest Africa 1110 Basaltic shergottite (Africa*)
Sayh al Uhaymir 060 Basaltic shergottite (Oman)
Sayh al Uhaymir 090 Basaltic shergottite (Oman)

*) Morocco or surrounding countries.

The preliminary text of the 2002 Meteoritical Bulletin, including the
above meteorites and those in E-mail Announcements 86-2 and 86-3,
may by viewed at:

    http://www.uark.edu/campus-resources/metsoc/metbull/mb86.pdf

***PLEASE REPORT ERRORS BY 14 APRIL 2002 TO: jgrossman_at_usgs.gov

All information in this e-mail and on the above-cited Meteoritical
Bulletin webpage is subject to revision until final publication in
the summer of 2002.

===========================================================
                      ANNOUNCEMENTS
===========================================================

Dhofar 378 18°9.5' N, 54°6.8' E
  Oman
  Found 2000 June 17
  Martian meteorite (basaltic shergottite)
A single stone of 15 g, covered with fresh black fusion crust, was
recovered by an anonymous finder within the province of other Dhofar
meteorites. Classification and description: (Y. Ikeda and M. Kimura,
Dept. of Materials and Biological Sciences Ibaraki; H. Takeda,
Chiba): It has a doleritic or microgabbroic texture, and the grain
sizes of the main minerals (pyroxenes and plagioclase glass) are
about 1 mm across. It consists mainly of ferroan pyroxenes (augite
and pigeonite), and plagioclase glass with quenched plagioclase
rims. Minor minerals are hedenbergite, pyroxferroite, fayalite,
silica, Ti-rich magnetite, ilmenite, sulfide, phosphate, and
rhyolitic glass. The Fe/(Mg+Fe) ratios of pyroxenes (augite and
pigeonite) range from 0.40 to more than 0.90, those of hedenbergite
from 0.97 to 0.99, and olivine from 0.90 to 0.98. The original
plagioclase grains were transformed to plagioclase glass (An35 to
An55) by an intense impact shock, then quenched plagioclase of the
same composition a few tens of mm up to one hundred mm in width at
the boundaries between the plagioclase glass and other minerals.
Oxygen isotopic composition (T.K. Mayeda and R.N. Clayton, UChi):
d18O == +4.46 permil, d17O == +2.52 permil. This meteorite was
recovered from an area near the Dhofar 019 basaltic shergottite, but
the two meteorites are probably not paired. Dhofar 019 is doleritic
and contains olivine grains with Fe/(Mg+Fe) ratios of 0.4-0.75,
whilst these seem to be absent from Dhofar 378. Pyroxenes in Dhofar
019 are more magnesian than in Dhofar 378. Specimens: type specimens
0.445 g & 0.054 g, Ibaraki; 2.74 g MPI; main mass is with the
anonymous finder.


Grove Mountains (GRV) 99027 73°06'01" S, 75°14'13" E
  Antarctica
  Found 2000 February 8
  Martian meteorite (lherzolitic shergottite)
This meteorite weighs 9.97 g, and most of the surface is covered by
fusion crust. Classification and Mineralogy (Lin and B. Miao, GIG;
H. Wang & C. Lin, NU): It is composed mainly of coarse-grained
orthopyroxene, olivine, clinopyroxene and plagioclase, with minor
opaque minerals. There are two textures. In the larger part of the
sections, olivine occurs as rounded euhedral grains, poikilitically
enclosed in a megacryst of orthopyroxene; in the other side of the
sections, it shows a cumulate texture, consisting of euhedral
orthopyroxene, clinopyroxene, olivine and interstitial plagioclase.
Chromite, the most common opaque phase, is euhedral and enclosed in
pyroxenes. The mineral assemblage and textures are similar to the
Allan Hills (ALHA) 77005 lherzolite. The FeO/MnO (wt%) ratio of
orthopyroxene is 34+/-5. Compositions of orthopyroxene (En66-78Fs20-
26Wo2-8), clinopyroxene (En48-52Fs13-15Wo34-39), olivine (Fa22-30)
and plagioclase (An49-55Ab44-50Or<1) overlap with the ranges in
ALHA77005. Fracturing and undulose extinction in silicates are
strong. Plagioclase is commonly deformed, and partially turns into
maskelynite along the boundaries of grains. The shock stage is S4;
weathering grade, W1. The meteorite is curated at PRIC.

Northwest Africa 856
  unknown location
  Found 2001 March
  Martian meteorite (basaltic shergottite)
A single stone of 320 g was found in Morocco in March 2001. The exact
location of find is unknown and the meteorite was referred to under
the pseudonym "Djel Ibone". The meteorite has a fine-grained basaltic
texture consisting mainly of pyroxene (70 vol%) and maskelynite (23
vol%). Accessory minerals include merrillite, apatite, pyrrhotite,
chromite, Fe-Ti oxides, silica (stishovite) and baddeleyite. Melt
pockets with phenocrysts and submicron-sized needles of stishovite
are present. Pyroxenes are highly fractured. Calcite veins formed by
terrestrial weathering cross-cut the specimens. Classification and
mineralogy (A. Jambon, UPVI, V. Sautter, MNHNP, Ph. Gillet, ENSL):
pyroxenes are pigeonite, En48Fs39Wo13, and augite, En36Fs32Wo32;
maskelynite composition is An41-47Ab57-51Or2. Geochemistry (J.-A.
Barrat, UAng and Ch. Göpel, IPGP): bulk composition in wt% is 0.81
TiO2, 6.83 Al2O3, 17.8 FeO*, 0.49 MnO, 9.51 MgO, 10.2 CaO, 1.28
Na2O, 0.13 K2O. Trace elements 77 ppm Ni and a REE pattern similar to
that of Shergotty and Zagami. Key element weight-ratios are FeO*/MnO
~30, Na/Al ~0.40, K/La of 500 and Ga/Al of 4.1x10-4. Abundances of Ba
and Sr and the Th/U ratio indicate that terrestrial weathering is
minor. Specimens: type specimen, 16 g, ENSL; main mass, Fectay.

Northwest Africa 1068
  Morocco
  Found 2001 April
  Martian meteorite (basaltic shergottite)
In 2001 April, meteorite hunters of the local team of "La Mémoire de
la Terre" recovered 23 stones (one large mass, 522 g, and 22 small
fragments, <20 g; total known mass, 576.77 g) in the Moroccan Sahara.
Rocks are greenish-brown and partially coated by desert varnish; no
fusion crust; cracks filled with terrestrial calcium carbonate. Thin
shock veins and small melt pockets are abundant. Classification,
mineralogy and bulk chemistry (J.-A. Barrat, UAng, A. Jambon, UPVI,
M. Bohn, I-CB, Ph. Gillet, ENSL, V. Sautter, MNHNP, Ch. Göpel, IPGP,
M. Lesourd, SCIAM): consists of olivine (50 um to 2 mm) in a fine-
grained groundmass (average grain size ~100 um) of euhedral to
subhedral pyroxene crystals and interstitial maskelynite; minor
phases are chromite, Ti-chromite, ilmenite, ulvöspinel, sulfides,
merrillite, apatite, and a K-rich mesostasis; impact melt pockets (up
to 1.5 mm long) contain pyrrhotite spherules. Modal abundances of
impact melt pockets and calcite free areas: 52 vol% pyroxenes, 22 %
maskelynite, 21 % olivine, 2 % phosphates, 2 % opaque oxides and
sulfides, and 1 % K-rich mesostasis. Mineralogy: olivine (Fa28 to
Fa58); pyroxenes: pigeonite (En57Wo5Fs28 to En40Wo13Fs47; fe# (100
Fe/(Fe+Mg) == 29-54 at. %) and augite (En55Wo21Fs24 to En35Wo28Fs36;
fe# == 29-51 at. %) are present as separate crystals in roughly equal
volume proportions; maskelynite is zoned (An53Ab45Or2 to An49Ab48Or3)
but is locally An-poor (An35Ab57Or8); FeO-rich merrillite (FeO 1.3
and 2.8 wt.%); apatites, Cl 0.5-2.5 wt% and F 1.1-6.4 wt%; chromite
have Ti-rich rims; ulvöspinels contain fine ilmenite lamellae (< 1
um thick). An interstitial K-rich component, probably a shock-
produced glass of alkali feldspar and silica, is generally associated
with Fe-Ti oxides. Bulk chemistry: Al-poor ferroan basaltic rock,
rich in MgO with major element abundances similar to those reported
for EETA79001 lithology A. Key element weight ratios are Fe/Mn == 45,
Al/Ti == 6.6, Na/Ti == 1.83, and Na/Al == 0.28. REE pattern similar to
Shergotty, Zagami, and Los Angeles. Specimens: type specimen, 20 g
and 2 polished sections, ENSL; main mass, Fectay.

Northwest Africa 1110
  Morocco
  Purchased 2001 November
  Martian meteorite (basaltic shergottite)
G. and A. Hupe (Hupe) received a small sample of this meteorite in
2001 September and bought the rest from a dealer in Erfoud, Morocco
in 2001November . The weight of the total material purchased is 118
g. The place of recovery is believed to be in Morocco.
Classification and mineralogy (A. Irving and S. Kuehner, UWS):
consists of olivine phenocrysts in a fine-grained groundmass of
complexly-zoned pigeonite and homogenous maskelynite, Ab46Or2, with
minor ilmenite, Ti-magnetite and pyrrhotite. Euhedral to subhedral
olivine has Mg-rich cores (Fa28, FeO/MnO == 50) and narrow Fe-rich
rims (Fa51, FeO/MnO == 53) and contain inclusions of chromite and
glass; augite (Fs33Wo21) occurs as rare inclusions in olivine;
pigeonite is zoned, Fs28Wo9 to Fs40Wo15 and FeO/MnO == 30; presence
of rare chlorapatite in mesostasis. Secondary features include minor
barite, commonly associated with chromite inclusions in olivine,
calcite, in a cross-cutting glass veinlet, and narrow zones of K-Al-
bearing glass or clay minerals along grain boundaries between
pyoxene and maskelynite. Mineral composition indicates that this rock
is possibly paired with NWA 1068. Specimens: type specimen, 20 g and
several thin sections, UWS; main mass, Hupe.

Sayh al Uhaymir 060 20°58.8' N, 57°19.1' E
  Oman
  Found 2001 June 27
  Martian meteorite (basaltic shergottite)
A small 42.28 g partially crusted grey-greenish stone was found near
to the area of previous finds of Sayh al Uhaymir 005/008/051/094.
All five meteorites seem to be paired. Mineralogy and classification
(S. Afanasiev, Vernad): has a porphyritic texture with large olivine
phenocrysts (Fo63.1-70.8) set in a groundmass consisting of
maskelynite (An61.4-68.3 Or0.5-1.6) and pigeonite (En60-69.6 Wo7.1-
8.6), augite (En47 Wo35) is rare; shock stage, S5; slight weathering.
Analyzed by Dr. N. N. Kononkova (Vernad). Specimens: type specimen,
9.5 g, Vernad; main mass with anonymous finder

Sayh al Uhaymir 090 21°00.0' N, 57°19.2' E
[This 94.84 g stone is probably paired with Sayh al Uhaymir 060, as
well as 005/008/051/094]
Received on Fri 05 Apr 2002 03:21:08 PM PST