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Northwest Africa 12531 | |||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 12531 This is an OFFICIAL meteorite name. Abbreviation: NWA 12531 Observed fall: No Year found: 2018 Country: (Northwest Africa) Mass: 530 g | ||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 100 approved meteorites classified as Eucrite-melt breccia. [show all] Search for other: Achondrites, Eucrites, and HED achondrites | ||||||||||||||||||||||||||||||
Comments: | Approved 31 Aug 2019 | ||||||||||||||||||||||||||||||
Writeup |
Writeup from MB 108:
Northwest Africa 12531 (NWA 12531) (Northwest Africa) Purchased: 2018 Classification: HED achondrite (Eucrite, melt breccia) History: Twenty-three identical stones with a total known weight of 530 g were found in Western Sahara in 2018. The samples were purchased from a prospector in Rissani in 2018 and subsequently obtained by David DGregory during the 2019 Tucson Gem and Mineral Show. Physical characteristics: Samples are irregularly shaped, lack fusion crust and are dark gray with light-colored clasts. Vesicles are visible on surface. Some samples appear to be composed mostly of melt and contain higher density of vesicles. Petrography: Description and classification (A. Love, App): A representative 23 g individual displaying the brecciated and vesicular melt textures was selected as the type specimen for description and analysis. The sample is a breccia composed of rounded clasts of coarse-grained (1.2 mm pyroxenes and 1 mm plagioclase), basaltic textured eucrite and related mineral debris set within a vesicular, quench-textured melt matrix. Clasts contain lithic fragments with embayed, exsolved pyroxenes surrounded by vesicular plagioclase. Additional minerals are: Si polymorphs, rare baddeleyite, phosphate, zircon, Ti-poor (3 wt% TiO2) and rich (<18 wt% TiO2) chromite which is sometimes inter-grown with ilmenite, troilite and Fe metal. Geochemistry: (A. Love, App) Basaltic eucrite clasts: low Ca pyroxene Fs55.2±5.3Wo2.5±1.2 (Fs48.8-63.6Wo1.9-6.3), Fe/Mn=29.6, Mg#35.0-48.6, n=12; high Ca pyroxene Fs22.6±2.8Wo44.1±0.6, N=12; Plagioclase An92.1±0.7Or0.2±0.0, N=6. Melt Matrix: Pigeonite Fs64.4±6.2Wo18.6±3.8, Fe/Mn=34.7, Mg#=8.7-38.2, N=6. Classification: Eucrite-melt breccia. Specimens: David DGregory holds the remaining 22 individuals that comprise the mass of this meteorite. One partially cut stone weighing 21.15 g and a polished thin section comprise the type specimen and are on deposit at App. | ||||||||||||||||||||||||||||||
Data from: MB108 Table 0 Line 0: |
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Institutions and collections |
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013) Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010) DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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Geography: |
Statistics: This is 1 of 9589 approved meteorites from (Northwest Africa) (plus 1869 unapproved names) | ||||||||||||||||||||||||||||||
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Revision history: |
This lists important revisions made to data for this record.
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