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Northwest Africa 13532
Basic information Name: Northwest Africa 13532
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13532
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 115 g
Classification
  history:
Recommended:  Mesosiderite-B2/3    [explanation]

This is the only approved meteorite classified as Mesosiderite-B2/3.
Search for other: Class A mesosiderites, Mesosiderites, and Metal-rich meteorites
Comments: Approved 19 Nov 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13532 (NWA 13532)

(Northwest Africa)

Purchased: 2017

Classification: Mesosiderite-B2/3

History: John Shea and Christopher Colvin purchased the meteorite in 2017 from Mike Miller. John Shea sent material to Cascadia for classification and transferred his remaining material to Christopher Colvin.

Physical characteristics: Exterior of the sample is irregular, with higher areas that are smoother and darker than the lower areas, which are rougher, pitted, and dark brown. Projecting areas show metal. Cut face shows a subequal mix of metal and silicates.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): In thin section, the sample consists of metal (with minor troilite along with about 10-20% weathering products) and mm- to cm-sized silicate clasts, primarily low-Ca pyroxene set in a predominantly granular matrix composed chiefly of low-Ca pyroxene, plagioclase feldspar and a silica polymorph. Matrix grades into clasts. Some orthopyroxene clasts are zoned, with more magnesian cores. At least one olivine clast is present with a moderately developed corona structure. Silica polymorph grains are equant to tabular and typically less than 100 microns across, although some laths are up to 1 mm long. Calcic pyroxene occurs as elongate patches within low-Ca pyroxene and at grain margins. Chromite and merrillite are accessory minerals. Overall, orthopyroxene is more abundant than plagioclase feldspar.

Geochemistry: Mineral compositions and geochemistry: Low-Ca pyroxene: Fs30.9±6.2Wo2.2±0.8, N=35; High-Ca pyroxene Fs15.7±0.9Wo42.9±0.7, N=12; olivine Fa37.2±0.1, N=4; plagioclase An90.7±2.2Or0.7±0.1Ab8.6±2.1, N=14.

Classification: Type B based on observation that pyroxene is more abundant than plagioclase. Type2/3 B mesosiderite based on texture and mineralogy.

Specimens: Cascadia holds 22.5 g in two pieces, as well as a polished thin section and butt.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Internet
Date:P 2017
Mass (g):115
Pieces:1
Class:Mesosiderite-B2/3
Fayalite (mol%):37.2±0.1 (N=4)
Ferrosilite (mol%):30.9±6.2 (N=35); 15.7±0.9 (N=12)
Wollastonite (mol%):2.2±0.8 (N=35); 42.9±0.7 (N=12)
Classifier:M. Hutson and A. Ruzicka, Cascadia
Type spec mass (g):22.5
Type spec location:Cascadia
Main mass:Christopher Colvin
Comments:Lab number CML 0976; submitted by Alex Ruzicka
Institutions
   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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7482 approved meteorites from (Northwest Africa) (plus 1988 unapproved names)

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