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Northwest Africa 7489
Basic information Name: Northwest Africa 7489
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7489
Observed fall: No
Year found: 2012
Country: Morocco
Mass:help 248 g
Classification
  history:
Recommended:  R3.5-4    [explanation]

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
Writeuphelp
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:
  • Bischoff, A. (2000) Mineralogical characterization of primitive, type-3 lithologies in Rumuruti chondrites. Meteorit. Planet. Sci. 35 699-706 (link)
Data from:
  MB99
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P Aug 2012
Mass (g):248
Pieces:1
Class:R3.5-4
Fayalite (mol%):31.7±12.6 (n=37)
Ferrosilite (mol%):12.9±7.4
Wollastonite (mol%):1.0±1.5
Classifier:C. Agee, UNM
Type spec mass (g):20.71
Type spec location:UNM
Main mass:Adam Bates
Comments:Submitted by C. Agee
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)
Catalogs:
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
Find references in NASA ADS:
Find references in Google Scholar:
Geography:

Morocco
Coordinates:Unknown.

Statistics:
     This is 1 of 1374 approved meteorites from Morocco (plus 16 unapproved names) (plus 1 impact crater)

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