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| Northwest Africa 11756 | |||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 11756 This is an OFFICIAL meteorite name. Abbreviation: NWA 11756 Observed fall: No Year found: 2017 Country: Morocco Mass:  840 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 55 approved meteorites classified as Brachinite. [show all] Search for other: Brachinites, Primitive achondrites | ||||||||||||||||||||||||||||||
| Comments: | Approved 26 May 2018 | ||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 107:
Northwest Africa 11756 (NWA 11756) Morocco Purchased: 2017 Sep Classification: Primitive achondrite (Brachinite) Petrography: (K. Metzler, IfP) Olivine-dominated ultramafic rock with metamorphic texture (~120° triple junctions), consisting of olivine, low-Ca pyroxene, and Ca-pyroxene grains up to ~0.8 mm. Metal is replaced by weathering products which are also concentrated along grain boundaries. Accessories are Cr-Al-spinel (up to 700 µm) and weathered FeS. No plagioclase was found. Geochemistry: Mineral compositions and geochemistry: Olivine grains (n=12): Fa26.8±0.2, mean Fe/Mn (at.)= 58; Low-Ca pyroxene grains (n=12): Fs22.1±0.4Wo2.1±0.1. Ca-pyroxene grains (n=5): Fs9.1±0.2Wo43.6±0.5. The concentration of Cr2O3 in olivine and pyroxene is <0.1 wt% and 0.3 wt%, respectively. Composition of Cr-spinel (n=2; at.): Cr/(Cr+Al)=0.78; TiO2 1.4-1.5 wt%. SEM analyses of large thin section areas reveal that this sample is nearly devoid of aluminum. Classification: Brachinite, based on metamorphic texture, grain size, modal composition, absence of plagioclase, and mineral chemistry. | ||||||||||||||||||||||||||||||
| Data from: MB107 Table 0 Line 0: |
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| Institutions and collections |
IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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| Photos: |
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Geography:
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Statistics: This is 1 of 1972 approved meteorites from Morocco (plus 37 unapproved names) (plus 1 impact crater) | ||||||||||||||||||||||||||||||