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Northwest Africa 5789
Basic information Name: Northwest Africa 5789
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 5789
Observed fall: No
Year found: unknown
Country: Morocco
Mass:help 49 g
Meteoritical Bulletin:  MB 97  (2010)  Shergottite
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 326 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 10 Dec 2009
Writeup from MB 97:

Northwest Africa 5789


Find (found January 2009, purchased May 2009)

Achondrite (Martian, olivine-phyric shergottite)

History: A small chip from one of three crusted stones found together in Morocco was sent from a dealer in Erfoud to Greg Hupé , and subjected to preliminary testing at UWS. Subsequently the stones were purchased in May 2009 by Stefan Ralew and Martin Altmann.

Physical characteristics: A 49 g partly crusted stone, naturally broken into three pieces that fit together (Fig. 4a). The interior consists mainly of pale yellowgreen olivine macrocrysts in a light brownish-gray, finer-grained matrix (Fig. 4b). No maskelynite is evident. Several exterior sides are coated by glossy black fusion crust, which contains embedded rounded quartz grains.

Petrography: (A. Irving and S. Kuehner, UWS; J. Gross, A. Treiman, K. Robinson, LPI) Small (up to 1 mm), zoned olivine macrocrysts (in multi-crystalline clusters) with narrow ferroan rims are set in a finer grained groundmass composed mainly of prismatic low-Ca pyroxene grains with accessory olivine, chromite, pyrrhotite, and small regions of mesostasis (approximately 2 vol%) composed of subparallel, laminar to sheaf-like intergrowths of pigeonite, intermediate plagioclase, silica, ilmenite, and merrillite. The pyroxenes exhibit chaotic compositional zoning, with low-Ca pyroxene cores, regions of pigeonite and augite, and narrow ferropigeonite rims.

Geochemistry: Olivine macrocrysts (cores Fa15.6–16.6, FeO⁄MnO = 45.2–49.4; mantle Fa22.6, FeO⁄MnO = 47.6; rim Fa45.4, FeO⁄MnO = 58.9), matrix olivine (Fa47.3, FeO⁄MnO = 61.1), low-Ca pyroxene (cores as magnesian as Fs17.1Wo1.6, FeO⁄MnO = 30.9), pigeonite

Classification: Achondrite (Martian, olivine-phyric shergottite). This specimen has mineralogical and bulk compositional similarities to Yamato 980459980497, but differs from those stones in having very little mesostasis.

Specimens: A total of 9.8 g, two polished thin sections and a polished mount are on deposit at UWS; a further 5.6 g of material is held by A. Treiman (LPI) and another 3.3 g at UAb. The remaining material is held by anonymous collectors and institutions.

Fig. 4. a) A 29.7 g crusted piece of NWA 5789. b) A 1.8 g
fragment showing large olivine grains. Cube for scale is 1 cm.

Data from:
  Table 1
  Line 263:
Origin or pseudonym:Morocco
Date:January 2009
Mass (g):49
Fayalite (mol%):15.6-16.6
Ferrosilite (mol%):17.1
Wollastonite (mol%):1.6
Classifier:A. Irving, S. Kuehner, UWS
Type spec mass (g):9.8+
Type spec location:UWS+
Main mass:Anon
Comments:Olivine-phyric shergottite. See written description
   and collections
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)
LPI: Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058 , United States; Website (institutional address; updated 20 Jun 2022)
Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private address)
References: Published in Meteoritical Bulletin, no. 97, MAPS 45, 449-493 (2010)
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     This is 1 of 2093 approved meteorites from Morocco (plus 32 unapproved names) (plus 1 impact crater)

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