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Northwest Africa 14599
Basic information Name: Northwest Africa 14599
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14599
Observed fall: No
Year found: 2021
Country: (Northwest Africa)
Mass:help 500 g
Classification
  history:
Recommended:  Mesosiderite-A2/3    [explanation]

This is the only approved meteorite classified as Mesosiderite-A2/3.
Search for other: Class A mesosiderites, Mesosiderites, and Metal-rich meteorites
Comments: Approved 29 Jan 2022
Writeuphelp
Writeup from MB 111:

Northwest Africa 14599 (NWA 14599)

(Northwest Africa)

Purchased: January 2021

Classification: Mesosiderite-A2/3

History: Purchased in January 2021 by Yang Shun-Chung and Juan Chen from Ali Mtah in Tindouf, Algeria.

Physical characteristics: Single stone with slightly weathered fusion crust. A slice from the interior reveals a metal-rich surface.

Petrography: (D. Sheikh, Cascadia) Specimen represents a breccia primarily composed of angular to sub-rounded silicate lithic and mineral clasts (Av. 1 mm, up to 4 mm) and sub-rounded to rounded segregated domains of Fe-Ni metal (Av. 2 mm, up to 5 mm, ~25 % in studied thin section) set within a fine-grained fragmental matrix (~ 0.1 mm) composed of sub-angular to sub-rounded silicate grains and rounded blebs of Fe-Ni metal. The silicate portion (~75 % in studied thin section) consists of ~70 % pyroxene (some are poikiloblastic), ~24 % plagioclase, ~4 % silica, ~2 % olivine, and ~<1 % accessory troilite and chromite. Metal is relatively fresh with only a few weathering veins dispersed throughout the sample.

Geochemistry: Olivine (Fa31.4±2.3, range Fa29.3-34.3, FeO/MnO=49±5, n=4), Low-Ca Pyroxene (Fs27.1±4.2Wo3.2±1.2, range Fs23.1-33.2Wo2.0-4.8, FeO/MnO=35±4, n=7), Pigeonite (Fs31.1±1.6Wo7.7±0.7, range Fs28.9-33.2Wo6.9-8.8, FeO/MnO=34±5, n=5), Calcic Plagioclase (An95.2±2.9Or0.2±0.2, range An89.2-97.4Or0.1-0.8, n=11).

Classification: Mesosiderite-A2/3. Estimated modal abundance of plagioclase consistent with petrologic class A. Grade 2/3 is estimated due to this sample displaying textural characteristics consistent with both grade 2 (recognizable brecciation in thin section, presence of extremely fine-grained silicate grains (<10 μm) within the matrix, partial replacement of olivine by pyroxene, partial inversion of pigeonite to orthopyroxene) and grade 3 (Average matrix grain size of 0.1 mm, presence of poikiloblastic pyroxene grains, presence of segregated domains of Fe-Ni metal).

Specimens: 22.1 g at NHMLAC; main mass with Yang Shun-Chung and Juan Chen.

Data from:
  MB111
  Table 0
  Line 0:
Place of purchase:Algeria
Date:P January 2021
Mass (g):500
Pieces:1
Class:Mesosiderite-A2/3
Shock stage:low
Weathering grade:low
Fayalite (mol%):31.4±2.3
Ferrosilite (mol%):27.1±4.2, 31.1±1.6
Wollastonite (mol%):3.2±1.2, 7.7±0.7
Classifier:D. Sheikh, Cascadia
Type spec mass (g):22.1
Type spec location:NHMLAC
Main mass:Yang Shun-Chung and Juan Chen
Comments:Submitted by Daniel Sheikh
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)
NHMLAC: Natural History Museum of Los Angeles County 900 Exposition Blvd., Los Angeles, CA 90007 , United States; Website (institutional address; updated 17 Jul 2021)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names)

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