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Northwest Africa 5790
Basic information Name: Northwest Africa 5790
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 5790
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 145 g
Meteoritical Bulletin:  MB 97  (2010)  Nakhlite
Recommended:  Martian (nakhlite)    [explanation]

This is 1 of 32 approved meteorites classified as Martian (nakhlite).   [show all]
Search for other: Martian meteorites
Comments: Approved 29 Nov 2009
Writeup from MB 97:

Northwest Africa 5790

Northwest Africa

Find: Spring 2009

Martian meteorite (Nakhlite)

History: Found in the desert by nomads and purchased by A. Habibi in Erfoud (Morocco).

Physical characteristics: Two stones totaling 145 g, with millimeter-sized phenocrysts in a groundmass with pinkish luster. Very friable.

Petrography: (A. Jambon, O. Boudouma, D. Badia, UPVI): Millimeter-sized euhedral dominant augite with sharp rim zoning and faint irregular zoning inside. Subsidiary euhedral olivine phenocrysts of similar size, zoned to their core. Interstitial mesostasis contains dendritic oxides pyroxene, feldspar, silica, phosphate, and glass. Minor Cl-amphiboles in trapped melt inclusions. Mode (vol%) from back scatterd electron images: Augite 51.2, olivine 9.1, mesostasis 39.7, titanomagnetite <1%.

Mineral compositions (SEM and EMPA; A. Jambon, O. Boudouma, D. Badia, UPVI) and geochemistry (ICP-MS; J-A Barrat UBO): Zoned augite core (En35, Fs24, Wo40, and Fe⁄Mn = 32) sharp rim (En20, Fs43, Wo36, and Fe⁄Mn = 42), olivine progressively zoned from the core (Fa65 with Fe⁄Mn = 47) to the rim (Fa80 with Fe⁄Mn = 40). Rare Ti-magnetite phenocrysts Uv32Mt56Sp7Ct4 with fine ilmenite exsolutions. In the mesostasis dendritic crystals of Ti-magnetite: Uv52–74Mt38–19, acicular pyroxene (En7,Fs47Wo46 and Fe⁄Mn = 55), and olivine Fa88. Plagioclase An16Ab79Or5. Augite with 2–3wt% Cl.

Bulk major-element chemistry similar to other nakhlites; element ratios confirm Martian origin (K⁄La = 473, Ga⁄Al = 3.7x104); significantly higher proportion of mesostasis than other nakhlites with the highest Th, U, and rare earth elements (REE) concentrations reported for a nakhlite (e.g., Th = 0.85 ppm); REE pattern characterized by a strong light REE enrichment (La⁄Yb)n = 5.8, and Eu⁄Eu* = 0.86.

Oxygen isotopes (R. Greenwood and I. Franchi, OU): Δ17O = 0.30‰.

Specimens: A mass of 16 g, is on deposit at UPVI; 2.77 g UAb; 1.25g UWS; main mass, Habibi.

Data from:
  Table 1
  Line 264:
Place of purchase:Erfoud
Mass (g):145
Fayalite (mol%):65
Ferrosilite (mol%):24
Wollastonite (mol%):40
Classifier:Jambon, Boudouma, Badia, UPVI
Type spec mass (g):20
Type spec location:UPVI, UAb, UWS
Main mass:AHabibi
   and collections
OU: Planetary and Space Sciences Department of Physical Sciences The Open University Walton Hall Milton Keynes MK7 6AA United Kingdom, United Kingdom (institutional address; updated 8 Dec 2011)
UPVI: Université Pierre et Marie Curie (Paris VI),Case 110, 4 Place Jussieu, 75005 Paris, France (institutional address; updated 5 Oct 2014)
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)
AHabibi: Palms Hotel Club, Erfoud 52200, Morocco (private address; updated 3 Jan 2010)
UBO: Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, place Nicolas Copernic, F-29280 Plouzané Cedex, France (institutional address; updated 15 Sep 2017)
References: Published in Meteoritical Bulletin, no. 97, MAPS 45, 449-493 (2010)
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     This is 1 of 9776 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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