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Northwest Africa 4757
Basic information Name: Northwest Africa 4757
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 4757
Observed fall: No
Year found: 2004
Country: Morocco
Mass:help 5 g
Meteoritical Bulletin:  MB 93  (2008)  CM
Recommended:  CM2    [explanation]

This is 1 of 610 approved meteorites classified as CM2.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), CM chondrites, and CM-CO clan chondrites
Comments: Approved 6 Mar 2008
Revised 4 Aug 2008: final writeup
Writeup from MB 93:

Northwest Africa 4757


Find: October 2004

Carbonaceous chondrite (CM)

History: An anonymous buyer purchased the stone in Munich, Germany, in October 2004.

Physical characteristics: The single piece weighing 5 g is black and covered with black fusion crust.

Petrography: (M. A. Ivanova, Vernad.) The meteorite consists of fine-grained phyllosilicate matrix material, relict chondrules, sometimes with haloes, and relict aggregates embedded in altered matrix. All silicates from the objects in the meteorite are altered and replaced by phyllosilicate. Only one tiny grain of olivine was found in the matrix. The minor phases are ilmenite, chromite, sulfides, kamacite, taenite, tetrataenite, phosphates, Ca,Mg carbonates. Abundant phyllosilicates in the matrix are mostly serpentine.

Geochemistry: Mineralogy: olivine (Fa10; Fe/Mn=52, CaO = 0.06; MnO = 0.19 [both wt%]). Bulk composition (wt%): Al2O3 = 2.3, TiO2 = 0.09, FeO = 32.0, MgO = 22.7, MnO = 0.34, CaO = 2.4, Na2O = 0.26, K2O = 0.15, S = 5.3. Oxygen isotopic compositions: (I. A Franchi and R. C. Greenwood, OU, by laser fluorination): δ17O = 12.84; δ18O = 23.83; Δ17O = 0.45 (all ‰).

Classification: Carbonaceous chondrite (CM); minor weathering.

Type specimens: A total of 1 g sample and one thin section are on deposit at Vernad. An anonymous buyer holds the main mass.

Data from:
  Table 2
  Line 108:
Place of purchase:Munich, Germany
Mass (g):5
Type spec mass (g):1
Plots: O isotopes:  
   and collections
OU: Planetary and Space Sciences Department of Physical Sciences The Open University Walton Hall Milton Keynes MK7 6AA United Kingdom, United Kingdom (institutional address; updated 8 Dec 2011)
Vernad: Vernadsky Institute of Geochemistry and Analytical Chemistry, Russia (institutional address; updated 21 Feb 2016)
References: Published in Meteoritical Bulletin, no. 93, MAPS 43, 571-632 (2008)
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     This is 1 of 1852 approved meteorites from Morocco (plus 24 unapproved names) (plus 1 impact crater)

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