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Northwest Africa 7892
Basic information Name: Northwest Africa 7892
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7892
Observed fall: No
Year found: 2012
Country: Morocco
Mass:help 346 g
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  CO3.0
Recommended:  CO3.0    [explanation]

This is 1 of 21 approved meteorites classified as CO3.0.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites
Comments: Approved 28 Jun 2013
Writeuphelp
Writeup from MB 102:

Northwest Africa 7892 (NWA 7892)

Morocco

Purchased: 2012

Classification: Carbonaceous chondrite (CO3.0)

History: Purchased by Abdelhadi Aithiba in Morocco, 2012.

Physical characteristics: Single stone, distinctive polygonal, dark brown weathered fusion crust, saw-cut reveals many small chondrules in a very fine-grained dark-brown matrix.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows many PP, POP, and PO chondrules, most 50-300 μm, irregular shaped or fragmental chondrules common.

Geochemistry: (C. Agee and L. Burkemper, UNM) Random chondrule olivine range Fa0.3-56.8, mean=Fa17.5, n=22, chondrule ferroan olivine mean Fa30.7±13.4, Cr2O3=0.39±0.19 wt%, Fe/Mn=95±25, n=35; low-Ca pyroxene range Fs 0.8-41.3, mean Fs8.0, n=17; aluminous diopside Al2O3=8.76 wt%. (Karen Ziegler, UNM) Oxygen isotope mean values of analyses on 2 acid-washed aliquots of bulk sample, 1.2, 1.1 mg, gave δ17O= -8.851, -9.836, δ18O= -5.849, -6.906, Δ17O= -5.763, -6.190, (linearized, all permil).

Classification: Carbonaceous chondrite (CO3.0) estimated 3.05, based on mean Cr2O3=0.39 wt% in 35 chondrule ferroan olivines which is higher than that measured in the most primitive CO3 chondrite currently known (ALH 77307), but with higher standard deviation (σ-Cr2O3), analogous to the higher σ-Cr2O3 reported in type 3.05 ordinary chondrites QUE 97008, MET 00526, and EET 90161 (Grossman and Brearley, 2005). Oxygen isotopes values significant lower than literature CO bulk values, and slightly above the CCAM.

Specimens: 21 g including a probe mount on deposit at UNM, Abdelhadi Aithiba holds the main mass.

Bibliography:
  • Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)
Data from:
  MB102
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2012
Mass (g):346
Pieces:1
Class:CO3.0
Fayalite (mol%):0.3-56.8
Ferrosilite (mol%):0.8-41.3
Classifier:C. Agee, UNM
Type spec mass (g):21
Type spec location:UNM
Main mass:Abdelhadi Aithiba
Comments:Submitted by C. Agee
Plots: O isotopes:  
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. 102, MAPS 50, 1662, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Geography:

Morocco
Coordinates:Unknown.

Statistics:
     This is 1 of 1417 approved meteorites from Morocco (plus 15 unapproved names) (plus 1 impact crater)

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