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| Northwest Africa 15931 | |||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 15931 This is an OFFICIAL meteorite name. Abbreviation: NWA 15931 Observed fall: No Year found: 2016 Country: (Northwest Africa) Mass:  118 g | ||||||||||||||||||||||||||
| Classification history: |
This is 1 of 9 approved meteorites classified as E6. [show all] Search for other: Enstatite chondrites, Enstatite chondrites (type 4-7), and Enstatite-rich meteorites | ||||||||||||||||||||||||||
| Comments: | Approved 29 Sep 2023 | ||||||||||||||||||||||||||
| Writeup |
Writeup from MB 112:
Northwest Africa 15931 (NWA 15931) (Northwest Africa) Purchased: 2016 Apr Classification: Enstatite chondrite (E6) History: A 47 g end piece of the meteorite was sent to Cascadia by John Shea, who purchased the sample on April 2016 from Arizona Meteorites via ebay. The ebay listing stated that the meteorite was found in Morocco, but also that the provenance that was sent with the meteorite stated that it was found in Algeria in 2000. On January 19, 2021, Martin Goff emailed Cascadia that he had "recently acquired a box of NWA Chondrites that came from US collector john/Johannes Shea", including CML 0912. Physical characteristics: Physical Characteristics: Cascadia received an end cut with a brown irregular exterior from which material flakes off. The cut face is light brown with extensive darker brown veining. Petrography: (M. Hutson, A. Ruzicka, Cascadia): The thin section is substantially dark in plane-polarized light due to extensive veining by iron oxide/hydroxide weathering product, and contains two large (2 mm and 3 mm across) holes containing terrestrial infill. In BSE, the sample is composed mainly of coarse-grained enstatite and feldspar. Phases observed in BSE and confirmed by chemical analysis are enstatite, albitic feldspar (examined grains which appear to be single grains crossed by numerous weathering veins are ~50 µm across) schreibersite, remnant troilite grains containing thin lamellae and blocky grains of daubréelite, and an SiO2 polymorph. No olivine was observed. No metal has survived terrestrial weathering. Geochemistry: Low-Ca pyroxene: En97.7±0.3Fs0.9±0.3Wo1.4±0.04, N=24; Plagioclase feldspar: Ab79.5±0.7An16.0±0.5Or4.5±0.4, N=15. Classification: Enstatite chondrite (E6) based on mineral chemistry and texture. Because of the absence of metal, that has been entirely turned into oxide/hydroxide weathering products, it is not possible to assigne a EH or EL classification to this meteorite. Specimens: Cascadia holds 45.7 g in one piece, as well as a polished thin section and material in an epoxy butt. | ||||||||||||||||||||||||||
| Data from: MB112 Table 0 Line 0: |
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| Institutions and collections |
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011) |
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| References: | Published in Meteoritical Bulletin, no. 112, in preparation (2023)
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| Geography: |
Statistics: This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names) | ||||||||||||||||||||||||||