[meteorite-list] New Mars, Lunar Meteorites Found

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:46:25 2004
Message-ID: <200105232015.NAA00198_at_zagami.jpl.nasa.gov>

NEW MARS, LUNAR METEORITES FOUND

Below are excerpts from the latest Meteorical Bulletin which reports
on the recovery of two Mars meteorites and four lunar meteorites.
The Northwest Africa 817 Mars meteorite is rather significent find since
it is a nakhlite, the fourth nakhlite ever found, and the first since 1958.
Also, since Sayh al Uhaymir 094 was found near the location of
three other Sayh al Uhaymir Mars meteorites, it is assumed paired
with these other meteorites until proven otherwise. That means
the number of Mars meteorites goes up by just one, bringing the
current total to 18.

Incidently, I had attended the Costa Mesa gem & mineral show this past
weekend, where Marvin Kilgore had lunar meteorite NWA 773 on display.


Ron Baalke

-------------------------------------------------------------------------


                    THE METEORITICAL BULLETIN
              E-mail Announcement 85-5, May 23, 2001
         Jeffrey N. Grossman, Editor (jgrossman_at_usgs.gov)
          Jutta Zipfel, Co-editor for Saharan Meteorites
                  (zipfel_at_mpch-mainz.mpg.de)

Below, you will find the complete text of announcements of many new
meteorites that will be published in Meteoritical Bulletin, No. 85,
2001 July. Included are:

Northwest Africa 817 Martian meteorite found in Morocco*
Sayh al Uhaymir 094 Martian meteorite found in Oman
Dhofar 280 Lunar meteorite found in Oman
Dhofar 287 Lunar meteorite found in Oman
Northwest Africa 479 Lunar meteorite found in Morocco*
Northwest Africa 773 Lunar meteorite found in Morocco*

* - Morocco or surrounding countries.

The preliminary text of the 2001 Meteoritical Bulletin, including the
above meteorites and those in E-mail Announcements 85-1 through 85-4,
may by viewed at:

    http://www.uark.edu/campus-resources/metsoc/metbull/mb85.pdf

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

Northwest Africa 817
  Morocco
  Found 2000 December
  Martian meteorite (Nakhlite)
A 104 g stone was found in the desert of Morocco. Classification and
analysis (V. Sautter, MNHNP; J. Barrat and M. Lesourd, UAng; A.
Jambon, UPVI; P. Gillet, ENSL; C. Göpel and J. Joron, IPGP): an
unbrecciated, medium-grained, olivine-bearing clinopyroxenite with
cumulate texture; consists of zoned, euhedral, subcalcic augite (Wo38-
40 En38-27Fs24-34 and Fe/Mn = 39-31), olivine (zoned from Fa57 in
cores to Fa86 in rims, with Fe/Mn = 54-43) with crystallized magmatic
inclusions, and a three-component intercumulus mesostasis (glass
including minute amounts of sulfide droplets, Ti-magnetite with
unusual skeletal morphology containing ilmenite exsolution, and
acicular pyroxene); mineral modes (vol%), pyroxene = 69, olivine =
15, mesostasis = 15, and Fe-Ti oxides = 1; alteration (probably pre-
terrestrial) produced a hydrous ferrous silicate both in olivine and
in the glassy mesostasis; bulk major-element composition similar to
other nakhlites; element ratios confirm Martian origin (FeO*/MnO =
37, Na/Al = 0.40, K/La = 449, Ga/Al = 3.9x10-4); has a higher
proportion of mesostasis than other nakhlites; displays the highest
Th, U and rare earth elements (REE) concentrations ever reported for
a nakhlite (e.g. Th = 0.6 ppm); REE pattern characterized by a strong
light REE enrichment (Lan/Ybn = 4.89), and Eu/Eu* = 0.90. Oxygen
isotopes (M. Javoy and E. Petit, IPGP): D17O = +0.4 permil.
Specimens: 10 g, ENSL; main mass with B. Fectay and C. Bidaut.

Sayh al Uhaymir 094 20°59.469'N 57°20.326'E
  Oman
  Found 2001 February 8
  Martian meteorite (shergottite)
A 223.3 g partially crusted stone was found in the same area as Sayh
al Uhaymir 005, 008, and 051 by Marc Hauser and Lorenz Moser (Bern)
during a search for meteorites. All samples may be paired. Mineralogy
and classification (E. Gnos, Institute for Geological Sciences, Bern)
and B. Hofmann (NMB): the grey-greenish rock shows a gabbro-like
texture and contains phenocrysts of olivine (average maximum
dimension = 1.5 mm) displaying shock-twinning, mosaicism, and,
locally, oxidation; optically clear parts of olivines (Fo65-69) occur
in a fine-grained (average maximum grain size = 0.3 mm) groundmass
consisting of maskelynite (An55-64Or5-9) and pigeonite (En60-68Wo7-9)
with minor augite, chromite and pyrrhotite; partially recrystallized
veins and pockets of shock-melted glass containing vescicles are
abundant; x-ray tomography revealed that the specimen contains
approximately 0.4 vol% of pores up to 3 mm in size; shock stage, S5;
weathering grade, W1; small rusty pockets are Fe-hydroxide
replacements of an unknown pre-existing phase. Specimens: all in NMB.



Dhofar 280 19°19.6'N 54°47.0'E
  Oman
  Found 2001 April 14
  Lunar meteorite (anorthositic fragmental breccia)
A gray stone weighing 251.2 g was found in the Dhofar region of Oman.
Classification and mineralogy (M. Nazarov, Vernad): fusion crust
present; meteorite is a clast-rich fragmental breccia containing
numerous mineral fragments and clasts of feldspathic rocks embedded
in a glass-rich matrix; schlieren and vesicles are abundant;
feldspar, An91-98; pyroxene, En58-75Wo4-5; olivine, Fo60-77 (Fe/Mn
&#8776; 99 atomic); accessory minerals are Ti-rich chromite, ilmenite,
troilite, and Fe-Ni metal; terrestrial weathering not significant.
Dhofar 081 and Dhofar 280 are probably paired because the stones were
found close to one another and are similar in texture and mineral
chemistry. Specimens: type specimen, 50 g plus two sections, Vernad;
main mass with anonymous finder.

Dhofar 287 18°24.2'N 54°08.8'E
  Oman
  Found 2001 January 14
  Lunar meteorite (Low-Ti, olivine-pyroxene mare basalt breccia)
A dark gray, 154 g black stone without fusion crust was found in the
Dhofar region of Oman, 400 m from Dhofar 025. Classification and
mineralogy (M. Nazarov, Vernad; L. Taylor, UTenn): contains two
adjacent lithologies, mare basalt (95 vol%) and regolith breccia (5
vol%). Basaltic portion: consists of olivine (Fo70-45) and minor
augite (Wo30-40 En38-45) phenocrysts (up to 1 mm) set in a
subophitic, fine-grained (50-100 &#956;m) groundmass composed of
plagioclase (An85-75) and pyroxene (Wo10-25En2-50), with accessory
pyroxferroite, K-Ba feldspar, apatite, ilmenite, Ti-rich chromite,
ulvöspinel, baddeleyite, silica, tranquillityite, troilite, Fe-Ni
metal, and a fayalite + K-rich glass mesostasis; shock veins and
impact melt pockets are present; plagioclase is totally converted to
maskelynite; mineral modes (vol%) are pyroxene = 49, maskelynite =
26, olivine = 18, opaques = 4, impact melt = 2; whole-rock TiO2
content = 2.8 wt%; Fe/Mn = 75; a prominent negative Eu anomaly is
present; similar in composition to Apollo 12 mare basalts, but
distinctly higher in Na and incompatible elements. Regolith breccia
portion: clast-rich, with numerous lithic and mineral grains (up to
1 mm) cemented by fine-grained mineral fragments (<100 um) and minor
impact melt; dominated by low-Ti and VLT mare basalt lithologies;
minor highland material probably present; lithic clasts are fine-
grained, vitrophyric, granular to ophitic, basaltic rocks and impact
melt breccias; mineral fragments dominated by pyroxene, olivine, and
plagioclase; glass fragments and spherules also occur; plagioclase,
An98-66; olivine, Fo80-25; pyroxenes highly variable, Wo5-40En2-80;
main accessories are silica, fayalite, pyroxferroite, K-rich glass,
apatite, ilmenite, Ti-rich chromite, ulvöspinel, troilite, and FeNi
metal. Specimens: 32 g and two thin sections, Vernad; main mass with
anonymous finder.

Northwest Africa 479
  Possibly Khter n'Aďt Khebbach, Morocco
  Found 2000 November
  Lunar meteorite (mare basalt)
A 156 g stone was collected in Morocco in the area of Khter n'Aďt
Khebbach, however, the exact location is unknown. Classification and
mineralogy (J.-A. Barrat, UAng, A. Jambon, UPVI, Violaine Sautter,
MNHNP, Ph. Gillet, ENSL): consists of phenocrysts of olivine,
pyroxene and chromite in a groundmass of pyroxene and calcic
plagioclase; texture closely resembles that of NWA 032; mineral
compositions are identical to those reported for NWA 032 (see Met.
Bull. 84). Specimens: main mass with anonymous finder; type specimen,
8 g and 1 thin section, ENSL; 3.6 g, NHMV.

Northwest Africa 773 ~26°46'N ~12°49'W
  Western Sahara
  Found 2000 September
  Lunar Meteorite (cumulate olivine norite with regolith breccia)
Three stones of 359 g, 224 g and 50 g, totaling 633 g were sold to
Marvin Kilgore (SWML) by nomads who showed him the place of find on
a flat dry desert plain near Dchira, Western Sahara. Mineralogy and
classification (T. Fagan, UHaw, M. Kilgore, SWML): consists of two
distinct lithologies, cumulate rock and regolith breccia; weathering
grade, W1; shock stage, S5. Cumulate portion: modes (vol%) are
olivine = 54.7, pigeonite = 24.2, augite = 5, feldspar (including
minor K-feldspar) = 15.6, opaques (troilite, chromite, Fe-metal) =
0.5; olivine, Fa28-97, mean Fa31, FeO/MnO = 99+/-11 g/g; pigeonite,
En64Wo11, FeO/MnO = 53+/-6 g/g; augite, En49Wo36, FeO/MnO = 46+/-6
g/g; plagioclase, An88-91; Ba-rich K-feldspar, An3Ab4Or93 with
average BaO = 2.2 wt.%. Breccia portion: contains fragments of
cumulate portion as well as silica glass, hedenbergitic pyroxene,
volcanic rocks, and unusual lithic clasts with fayalite + Ba-rich K-
feldspar + silica + plagioclase; olivine and pyroxene in the breccia
have a slightly wider compositional range towards lower Mg/(Mg+Fe)
than in the cumulate portion of the rock. Chemical composition (D.
Mittlefehldt, JSC): Kreep-rich with strong negative Eu-anomaly. Noble
gases (O. Eugster, Physikalisches Institut, Bern): high solar wind
component, 4He/20Ne = 9, indicative of regolith material. Specimens:
type specimen, 15 g, NHM; main mass SWML.
Received on Wed 23 May 2001 04:15:46 PM PDT