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| Northwest Africa 7489 | |||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 7489 This is an OFFICIAL meteorite name. Abbreviation: NWA 7489 Observed fall: No Year found: 2012 Country: Morocco Mass:  248 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 5 Dec 2012 | ||||||||||||||||||||||||||
| Writeup |
Writeup from MB 99:
Northwest Africa 7489 (NWA 7489) Morocco Purchased: Aug 2012 Classification: R3.5-4 History: Purchased by Adam Bates in Morocco, August 2012. Physical characteristics: Single stone, fusion crust, with weathered orange-tinted coating, saw-cut reveals mostly scattered small chondrules, but some up to 3 mm, set in fine-grained, brown-orange groundmass. Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows numerous small to medium-sized PO, POP, and PP chondrules, most with mesostasis or glass, set in very fine-grained matrix. Brecciated, with a ~1 mm clast of R-chondrite matrix + chondrules imbedded in host R-chondrite. Geochemistry: (C. Agee and M. Spilde, UNM) (C. Agee and M. Spilde, UNM) Random sampling of chondrule olivines, range: Fa3.1-39.6, mean value Fa31.7±12.6, CV=40% (R3.5), Fe/Mn=78±21, NiO=0.20±0.13, n=37; chondrule low-Ca pyroxene Fs12.9±7.4Wo1.0±1.5 Fe/Mn=28±11, n=13; chondrule high-Ca pyroxene Fs10.5±1.2Wo45.6±1.1 Fe/Mn=47±10, n=2. Three distinct clasts were also analyzed to survey the range of petrologic types: Clast-#1 chondrules, olivine range: Fa8.3-40.9, mean value Fa31.0±13.0, CV=42% (R3.5), Fe/Mn=87±31, NiO=0.15±0.13, n=7; low-Ca pyroxene Fs19.5±5.6Wo2.7±3.9, Fe/Mn=23±8, n=12. Clast-#2 chondrules, olivine range: Fa22.1-44.3, mean value Fa36.5±5.8, CV=16% (R3.8), Fe/Mn=92±15, NiO=0.18±0.09, n=20; low-Ca pyroxene Fs8.0±7.0Wo1.0±1.9, Fe/Mn=23±13, n=20. Clast-#3 chondrules, olivine mean value Fa38.2±1.6, CV=4% (R4), Fe/Mn=83±7, NiO=0.31±0.08, n=20; low-Ca pyroxene Fs11.3±9.5Wo0.6±0.5, Fe/Mn=25±17, n=16. Ubiquitous chromite and pentlandite, minor troilite, no metal detected. Classification: Rumuruti chondrite (R3.5-4), petrologic type based on the coefficient of variation (CV) of chondrule olivine mean fayalite content in a random sampling of the probe mount and in three different clasts, which gave petrologic types 3.5, 3.5, 3.8, and 4 (n=84), see figure 8 from Bischoff (2000). Specimens: 20.71 g including a probe mount on deposit at UNM, Adam Bates holds the main mass. | ||||||||||||||||||||||||||
| Bibliography: |
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| Data from: MB99 Table 0 Line 0: |
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| 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) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
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Geography:
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Statistics: This is 1 of 2163 approved meteorites from Morocco (plus 32 unapproved names) (plus 1 impact crater) | ||||||||||||||||||||||||||