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| Northwest Africa 5789 | |||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 5789 This is an OFFICIAL meteorite name. Abbreviation: NWA 5789 Observed fall: No Year found: unknown Country: Morocco Mass:  49 g | ||||||||||||||||||||||||||
| Classification history: |
This is 1 of 307 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||||||
| Comments: | Approved 10 Dec 2009 | ||||||||||||||||||||||||||
| Writeup |
Writeup from MB 97:
Northwest Africa 5789 Morocco 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 980459⁄980497, 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 | ||||||||||||||||||||||||||
| Data from: MB97 Table 1 Line 263: |
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| Institutions 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) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 97, MAPS 45, 449-493 (2010)
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Geography:
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Statistics: This is 1 of 2012 approved meteorites from Morocco (plus 35 unapproved names) (plus 1 impact crater) | ||||||||||||||||||||||||||
