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| Northwest Africa 13455 | |||||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 13455 This is an OFFICIAL meteorite name. Abbreviation: NWA 13455 Observed fall: No Year found: 2019 Country: (Northwest Africa) Mass:  150 g | ||||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 4 approved meteorites classified as CO3-an. [show all] Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites | ||||||||||||||||||||||||||||||||
| Comments: | Approved 5 Dec 2020 | ||||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 109:
Northwest Africa 13455 (NWA 13455) (Northwest Africa) Purchased: 2019 Classification: Carbonaceous chondrite (CO3-an) History: The meteorite was purchased from a meteorite dealer in Morocco, possibly from the same lot as NWA 12957. Physical characteristics: Many small almost black fragments some of which covered by fusion crust. Petrography: The meteorite is a brecciated carbonaceous chondrite composed of small chondrules (mean diameter about 250 μm), mineral fragments, and rare CAIs embedded in a fine-grained Fe-rich matrix. Some objects are surrounded by accretionary dust rims. Opaque phases include metal, sulfides, and magnetite. Olivine and low-Ca pyroxene are highly unequilibrated. Phyllosilicates and carbonates appear to be absent. Geochemistry: Cr2O3 in ferroan olivine: 0.30±0.09 wt%, N=8; mean values of defocused matrix analyses (beam diamter 5 µm; all wt%; N=25): SiO2: 28.7, TiO2: 0.05, Na2O: 0.32, Cr2O3: 0.50, MgO: 14.3, MnO: 0.17, FeO: 36.4, Al2O3: 2.86, NiO: 2.16, P2O5: 0.65, S: 2.37, Total: 88.48; Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave: δ18O=-7.200, -8.292, -5.533; δ17O=-8.959, -9.822, -8.533; Δ17O= -5.157, -5.444, .5.612 (all per mil) Classification: Carbonaceous chondrite (CO3-an). The type 3 due to highly unequilibrated silicates and the absence of phyllosilicates and carbonates. Anomalous designation is from the oxygen isotopic composition. Pairing with NWA 12957 seems likely. | ||||||||||||||||||||||||||||||||
| Data from: MB109 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||||||||
| Institutions and collections |
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011) UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015) |
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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 9710 approved meteorites from (Northwest Africa) (plus 1853 unapproved names) | ||||||||||||||||||||||||||||||||
| Crosslinks: |
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| Also see: |
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| Revision history: |
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