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Northwest Africa 12736 | |||||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 12736 This is an OFFICIAL meteorite name. Abbreviation: NWA 12736 Observed fall: No Year found: 2015 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 140 approved meteorites classified as Achondrite-ung. [show all] Search for other: Achondrites, Ungrouped achondrites | ||||||||||||||||||||||||||||||||
Comments: | Approved 31 Jan 2020 | ||||||||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 109:
Northwest Africa 12736 (NWA 12736) (Northwest Africa) Purchased: 2015 Classification: Achondrite-ung Petrography: (J. Gattacceca, CEREGE) Blocky aggreagte of olivine and pyroxene with grain size 600 µm. Metal and troilite are present as veinlets, along silicate rims and as small aligned crystals within silicates. No graphite was observed; and no silicate zoning was observed. Geochemistry: Olivine Fa12.2±0.6, FeO/MnO 23.4±4.5, CaO 0.26±0.04 wt%, Cr2O3 0.50±0.04 wt% (n=6). Pyroxene: low-Ca pyroxene Fs10.9±0.2Wo4.7±0.1 (n=5), high-Ca pyroxene Fs6.6±0.1Wo37.8±0.3 (n=5), FeO/MnO 12.8±2.7 (n=10). Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 118 mg bulk sample is δ17O=0.05‰, δ18O=1.65‰ , Δ17O=-0.81‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively). Classification: Achondrite-ungrouped. The mineralogy is reminiscent of ureilites but significant differences are the absence of carbon material (graphite, diamond) and the absence of reduced rim in silicates. Oxygen isotopic composition is also distinct from that of ureilites. | ||||||||||||||||||||||||||||||||
Data from: MB109 Table 0 Line 0: |
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Plots: | O isotopes: | ||||||||||||||||||||||||||||||||
Institutions and collections |
CEREGE: CEREGE
BP 80
Avenue Philibert, Technopole de l'Arbois
13545 Aix-en-Provence Cedex 4
France, France (institutional address; updated 10 Jun 2023) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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Photos: |
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Geography: |
Statistics: This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names) |