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Northwest Africa 11880 | |||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 11880 This is an OFFICIAL meteorite name. Abbreviation: NWA 11880 Observed fall: No Year found: 2018 Country: (Northwest Africa) Mass: 32.9 g | ||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 2 approved meteorites classified as R3.5-4. [show all] Search for other: Rumuruti chondrites, Rumuruti chondrites (type 3) | ||||||||||||||||||||||||||||||
Comments: | Approved 17 Jul 2018 | ||||||||||||||||||||||||||||||
Writeup |
Writeup from MB 107:
Northwest Africa 11880 (NWA 11880) Northwest Africa Purchased: 2018 Jan Classification: Rumuruti chondrite (R3.5-4) Petrography: The sample is a breccia, consisting of light and dark clasts. The light clasts display well-defined chondrules surrounded by a fine-grained matrix. The dark clasts show very well-defined chondrules in a dark and glassy matrix. Mean apparent chondrule size is 550±377 μm in the dark clasts, and 694±316 μm in the light clasts. Maximum chondrule size is 2.65 mm. Undulatory extinction is visible in olivine grains. No oxidation rims are seen on sulphides or metal grains. Geochemistry: As determined by EPMA, Dark Clast olivine compositions are: Fa=31.3±27.6 (n=35), coefficient of variation CV%=43.7, Cr2O3 (wt%) = 0.14. Dark clast pyroxene compositions are: High Ca Pyroxene - Fs18.2±5.5En52.5±7.3Wo29.2±12 (n=4), Low Ca Pyroxene - Fs29.6±5.6En66.2±1.2Wo4.2±5.1, (n=5). Light Clast olivine compositions are: Fa40.9±0.6 (n=10), CV%=1.1, Cr2O3 (wt%) = 0.08. Light clast pyroxene compositions are: Fs13.7±3.4En43.9±0.7Wo42.4±4.0 (n=6) (V. Di Cecco, ROM) Classification: Pyroxenes: Dark/Unequilibrated Clast - High and low Ca pyroxenes occur in roughly equal proportions. Light/Equilibrated Clast - Ca pyroxene is dominant. This follows the summary of Bischoff et al. (2011) for R chondrites. Fa40.9±0.6 is consistent with reported composition of equilibrated R chondrites. CV% of 43.7 suggests petrologic type 3.5. | ||||||||||||||||||||||||||||||
Bibliography: |
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Data from: MB107 Table 0 Line 0: |
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Institutions and collections |
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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Geography: |
Statistics: This is 1 of 9627 approved meteorites from (Northwest Africa) (plus 1865 unapproved names) | ||||||||||||||||||||||||||||||
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Revision history: |
This lists important revisions made to data for this record.
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