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Northwest Africa 7557
Basic information Name: Northwest Africa 7557
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7557
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass:help 270 g
Classification
  history:
Meteoritical Bulletin:  MB 101  (2012)  Howardite
Recommended:  Howardite    [explanation]

This is 1 of 386 approved meteorites classified as Howardite.   [show all]
Search for other: Achondrites, HED achondrites, and Howardites
Comments: Approved 12 Dec 2012
Writeuphelp
Writeup from MB 101:

Northwest Africa 7557 (NWA 7557)

(Northwest Africa)

Purchased: 2011

Classification: HED achondrite (Howardite)

Petrography: The meteorite displays a brecciated texture with large mineral and lithic fragments set in a fine-grained cataclastic matrix. Mineral fragments are dominantly large diogenitic orthopyroxenes and calcic plagioclase. Subordinate lithic clasts include fine-grained basaltic eucrite clasts and fewer melt fragments. Pyroxene in eucritic clasts contains sub-μm wide Ca-rich exsolution lamellae. Accessory silica, Fe,Ni-metal, and chromite.

Geochemistry: Diogenitic orthopyroxene Fs25.3-26.3Wo2.1-4.8, FeO/MnO=29-33; exsolved Ca-pyroxene Fs41.3-59.7Wo14.6-31.6, FeO/MnO=30-32; calcic plagioclase An90.2, range 85.4-93.1

Data from:
  MB101
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2011
Mass (g):270
Pieces:1
Class:Howardite
Shock stage:low
Weathering grade:moderate
Classifier:A. Greshake, MNB
Type spec mass (g):20.2
Type spec location:MNB
Main mass:Andreas Grünemeyer
Comments:Submitted by Ansgar Greshake
Institutions
   and collections
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 101, MAPS 50, 1661, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7483 approved meteorites from (Northwest Africa) (plus 1994 unapproved names)

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