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| Northwest Africa 12921 | |||||||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 12921 This is an OFFICIAL meteorite name. Abbreviation: NWA 12921 Observed fall: No Year found: 2018 Country: (Northwest Africa) Mass:  566 g | ||||||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 100 approved meteorites classified as LL7. [show all] Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7) | ||||||||||||||||||||||||||||||||||
| Comments: | Approved 21 Nov 2019 | ||||||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 108:
Northwest Africa 12921 (NWA 12921) (Northwest Africa) Purchased: 2018 Classification: Ordinary chondrite (LL7) History: Marc Jost purchased the 566 g stone from Giorgio Tomellieri at the St. Marie aux Mines show in 2018. Physical characteristics: The rounded sample has a weathered brown exterior. A cut face shows the interior is light green in color and has a crystalline texture with visible flakes of metal and sulfide. Petrography: Description and classification (A. Love, App): Sample has a fine-grained, poikiloblastic texture composed of: 60 vol% Ol; 25 vol% Ca-poor and Ca-rich pyroxene and 14 vol% albitic plagioclase (avg length 112µm, n=53). Additional minerals are: troilite; pentlandite; chromite (average length 79µm, n=31); merrillite; kamacite and taenite. Recrystallization has overprinted and erased primary chondritic texture. Geochemistry: (A. Love, App): Olivine (Fa31.6±0.1, Fe/Mn=57.2±1.1, n=12); low Ca pyroxene (Fs26.1±0.2Wo2.7±0.4, CaO=1.1-1.7, n=6); high Ca pyroxene (Fs12.1±0.3Wo41.7±0.7, n=6); plagioclase (An10.9±0.1Or 5.9±0.2, n=2).Oxygen isotopes (K. Ziegler, UNM): analyses of 3 acid-washed mineral separates by laser fluorination gave, respectively, δ17O = 4.373, 4.214, 4.199; δ18O = 5.787, 5.526, 5.472; Δ17O = 1.318, 1.297, 1.310 (data are linearized all per mil). Classification: Ordinary Chondrite (LL7 C-S2 W1). LL based on oxygen isotopic composition, olivine and pyroxene compositions and magnetic susceptibility. Type 7 based on recrystallized poikiloblastic texture, equilibrated compositions, CaO content of low and high-Ca pyroxenes and size of plagioclase. Specimens: Marc Jost (SJS) holds the main mass. 2 slices weighing 35.4 g, a polished mount and a polished thin section are on deposit at App. | ||||||||||||||||||||||||||||||||||
| Data from: MB108 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||||||||||
| Institutions and collections |
UNM: Institute of Meteoritics
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015) App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013) SJS: Space Jewels Switzerland, 2555 Brügg, Switzerland (private address; updated 3 Jan 2010) |
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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 9699 approved meteorites from (Northwest Africa) (plus 1854 unapproved names) | ||||||||||||||||||||||||||||||||||
| Also see: |
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| Revision history: |
This lists important revisions made to data for this record.
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