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Northwest Africa 7909
Basic information Name: Northwest Africa 7909
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7909
Observed fall: No
Year found: 2004
Country: (Northwest Africa)
Mass:help 168 g
Meteoritical Bulletin:  MB 102  (2013)  Mesosiderite-C2
Recommended:  Mesosiderite-C2    [explanation]

This is 1 of 5 approved meteorites classified as Mesosiderite-C2.   [show all]
Search for other: Class C mesosiderites, Mesosiderites, and Metal-rich meteorites
Comments: Approved 27 Jul 2013
Writeup from MB 102:

Northwest Africa 7909 (NWA 7909)

(Northwest Africa)

Purchased: 2004

Classification: Mesosiderite (group C2)

History: The sample was purchased from a Moroccan trader by Mr. Thompson, and a portion was donated to Cascadia on May 3, 2004.

Physical characteristics: The hand specimen has faceted dark surfaces and brownish, broken faces; cut faces show rust splotches.

Petrography: (A.Ruzicka and K. Farley, Cascadia) Thin-section examination shows a silicate-metal breccia with ~15-20% metal, ~2-5% troilite, and lightly deformed low-Ca pyroxene present in both mineral and lithic clasts, set in a granoblastic groundmass of pyroxene and subordinate plagioclase. Low-Ca pyroxene often contains exsolution lamellae or blebs of high-Ca pyroxene. Metal is <20% altered (grade W1).

Geochemistry: Phase compositions are relatively equilibrated: low-Ca pyroxene Wo2.7±0.5 Fs23.7±1.1 Fe/Mn =26.7±4.1 (N=32), plagioclase An90.8±1.8 Or0.04±0.3 (N=14) (atomic units).

Classification: Stony-iron (mesosiderite). Textures and mineralogy suggest a relatively uncommon group C mesosiderite (dominated by low-Ca pyroxene) of textural type 2.

Specimens: 33.3 g and one polished thin section at Cascadia. Thompson holds the main mass.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2004
Mass (g):168
Shock stage:low
Weathering grade:W1
Ferrosilite (mol%):23.7±1.1
Wollastonite (mol%):2.7±0.5
Classifier:A. Ruzicka, Cascadia
Type spec mass (g):33.3
Type spec location:Cascadia
Main mass:Thompson
Comments:Lab number CML0202, Field number KH003.; submitted by A. Ruzicka
   and collections
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
Thompson: Edwin Thompson, 5150 Dawn St., Lake Oswego, OR 97035, United States (private address)
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
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     This is 1 of 9829 approved meteorites from (Northwest Africa) (plus 1851 unapproved names)

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