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Northwest Africa 4812
Basic information Name: Northwest Africa 4812
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 4812
Observed fall: No
Year found: 2006
Country: (Northwest Africa)
Mass:help 68 g
Classification
  history:
Meteoritical Bulletin:  MB 94  (2008)  CK
Recommended:  CK    [explanation]

This is 1 of 3 approved meteorites classified as CK.   [show all]
Search for other: Carbonaceous chondrites, CK chondrites, and CV-CK clan chondrites
Comments: Approved 17 Apr 2008
Writeuphelp
Writeup from MB 94:

Northwest Africa 4812

Northwest Africa

Find: 2006

Carbonaceous chondrite (CK)

History and physical characteristics: A 68 g stone was purchased in Erfoud, Morocco, by Stefan Ralew in 2006. Patchy distribution of dark gray fusion crust and desert etching.

Petrography: (T. Bunch and J. Wittke, NAU) dark interior with very dark chondrules and shock-melt clasts, the matrix is nearly opaque. Highly shocked and shock-darkened by melting to partial melting of matrix and redistribution of fine-grained magnetite similar to shock darkening of ordinary chondrites and redistribution of fine-grained metal droplets. Contains olivine, orthopyroxene, pigeonite, plagioclase, felsic glasses, Cr-magnetite, FeS, and pentlandite. The shock level is S5 and weathering grade is low.

Mineral compositions: Olivine, Fa30.3 (FeO/MnO = 110); orthopyroxene, Fs26.4Wo0.7 (FeO/MnO = 74); pigeonite, Fs21.1Wo12.1 (FeO/MnO = 64); plagioclase, An59.3 and magnetite, Cr2O3 = 3.64 wt% and Al2O3 = 1.26 wt%.

Classification: Carbonaceous chondrite (CK). High shock effects preclude further subtype classification.

Type specimen: A total of 6.9 g and one thin section are on deposit at NAU. S. Ralew is the main mass holder.

Data from:
  MB94
  Table 2
  Line 61:
State/Prov/County:Erfoud
Date:2006
Mass (g):68
Pieces:1
Class:CK
Shock stage:moderate-extensive
Classifier:T. Bunch and J. Wittke, NAU
Type spec mass (g):13.2
Type spec location:NAU
Institutions
   and collections
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
Ralew: Stefan Ralew, Kunibertstra├če 29, 12524 Berlin, Germany; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 94, MAPS 43, 1551-1588 (2008)
Find references in NASA ADS:
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Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6759 approved meteorites from (Northwest Africa) (plus 2047 unapproved names)

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