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Northwest Africa 6162
Basic information Name: Northwest Africa 6162
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6162
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 89 g
Meteoritical Bulletin:  MB 99  (2011)  Martian (shergottite)
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 324 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 16 Dec 2010
Writeup from MB 99:

Northwest Africa 6162 (NWA 6162)

Northwest Africa

Found: 2009 Mar

Classification: Martian meteorite (Shergottite)

History: A small stone was found in March 2010 near Lbirat in southern Morocco and purchased by Stefan Ralew and Martin Altmann.

Physical characteristics: A single very fresh 89 g stone completely coated by black fusion crust with shiny, dark olivine grains visible. The interior is light gray with obvious glassy maskelynite and larger pale yellow grains of olivine, and small pockets of black shock glass.

Petrography: (A. Irving and S. Kuehner, UWS): Porphyritic texture. Larger anhedral olivine grains (some in clusters, and containing Cr-rich chromite inclusions) are set in a groundmass composed mostly of pigeonite and plagioclase (maskelynite) with accessory olivine, chromite, pyrrhotite and Mg-bearing merrillite.

Geochemistry: Olivine (core Fa29.6-29.2, rim Fa34.9, FeO/MnO = 48.4-54.2), pigeonite (Fs22.9-28.6Wo5.0-9.7, FeO/MnO = 27.5-30.4), plagioclase (An62.1-65.8Or0.5-0.3). Oxygen isotopes (D. Rumble, CIW): acid-washed material analyzed by laser fluorination gave, respectively δ18O = 4.68, 3.98; δ17O = 2.75, 2.36; Δ17O = 0.288, 0.271 per mil. Bulk composition (M. Gellissen, XRF, U. Cologne; C. Herd, ICPMS, UAb): powder prepared from clean cutting dust gave the following elemental abundances (in wt.%): SiO2 46.6, FeO 18.3, MgO 21.8, CaO 5.1; (in ppm) La 0.25, Ce 0.66, Nd 0.61, Sm 0.43, Yb 0.75, Lu 0.12, Ni 220. The rare earth element abundances indicate that this is a depleted shergottite.

Classification: Achondrite (Martian, shergottite, olivine-phyric). This specimen is not paired with other shergottites from northwest Africa, but has mineralogical similarities to Sayh al Uhaymir 005 and pairings found in Oman. This specimen shows no evidence of terrestrial weathering, and is much fresher than most other known depleted olivine-phyric shergottites.

Specimens: A total of 17.8 g of type material, one polished thin section and a polished mount are on deposit at UWS; a further 3.2 g is held by J. Jones (JSC). The remaining material is held by anonymous collectors and institutions.

Data from:
  Table 0
  Line 0:
Place of purchase:Ouarzazate
Date:2009 Mar
Mass (g):89
Class:Martian (shergottite)
Shock stage:moderate
Weathering grade:very low
Fayalite (mol%):26.9-29.2; 34.9
Ferrosilite (mol%):22.9-28.6
Wollastonite (mol%):5.0-9.7
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):17.8
Type spec location:UWS
Main mass:S. Ralew
Comments:Submitted by A. Irving
Plots: O isotopes:  
   and collections
JSC: Mailcode XI, 2101 NASA Parkway, NASA Johnson Space Center, Houston, TX 77058, United States; Website (institutional address; updated 28 Jul 2022)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private address)
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
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     This is 1 of 9772 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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