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Northwest Africa 10720
Basic information Name: Northwest Africa 10720
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10720
Observed fall: No
Year found: 2015
Country: Mauritania
Mass:help 1015 g
Classification
  history:
Meteoritical Bulletin:  MB 105  (2016)  Martian (nakhlite)
Recommended:  Martian (nakhlite)    [explanation]

This is 1 of 32 approved meteorites classified as Martian (nakhlite).   [show all]
Search for other: Martian meteorites
Comments: Approved 20 Jun 2016
Writeuphelp
Writeup from MB 105:

Northwest Africa 10720 (NWA 10720)

Mauritania

Purchased: 2015 Dec 1

Classification: Martian meteorite (Nakhlite)

History: Purchased 1 Dec 2015 in Mauritania. Recovered from near the border region of Western Sahara, Mauritania and Algeria.

Physical characteristics: Several identical appearing stones. The exterior is partially covered by black fusion crust. Freshly broken surfaces reveal a mixture of mm-size, dark-green pyroxene grains and interstitial cream-colored feldspar.

Petrography: (C. Agee, UNM) This meteorite has an ophitic texture consisting of 75% augite, 15% feldspar, and 5% olivine. Some augite crystals are prismatic and up to 2 mm in length. There are two feldspars present, oligoclase and alkali feldspar, no maskelynite was observed; feldspar commonly occupies interstices between augite grains. Augites show igneous zoning with Fs-rich rims, olivines are fayalitic and fairly uniform in composition. Apatite was observed.

Geochemistry: (C. Agee and M. Spilde, UNM) Olivine Fa86.9±0.8, Fe/Mn=44±2, n=5; augite Fs29.0±7.4Wo39.9±1.3, range Fs23.0-48.1Wo38.4-41.1, Fe/Mn=35±3, n=20; plagioclase An21.8±2.2Ab72.8±1.5Or5.4±1.4, n=7; alkali feldspar An6.7±0.4Ab73.0±1.2Or20.3±1.6, n=3. Oxygen isotopes (K. Ziegler, UNM) All samples were acid-washed and analyzed by laser fluorination δ18O = 4.581, 4.903, 4.802; δ17O = 2.669, 2.854, 2.800; Δ17O = 0.250, 0.265, 0.265 (linearized, all per mil).

Classification: Martian (nakhlite). This is a martian meteorite based on the oxygen isotope values and the Fe/Mn of augite and olivine. It is a nakhlite based on the high percentage of augite present. Paired with NWA 10153.

Specimens: 23.96 g including a probe mount on deposit at UNM, DPitt holds the main mass.

Data from:
  MB105
  Table 0
  Line 0:
Place of purchase:Mauritania
Date:P 2015 Dec 1
Mass (g):1015
Pieces:several
Class:Martian (nakhlite)
Shock stage:moderate
Weathering grade:low
Fayalite (mol%):86.9±0.8
Ferrosilite (mol%):29.0±7.4
Wollastonite (mol%):39.9±1.3
Classifier:C. Agee, UNM
Type spec mass (g):23.96
Type spec location:UNM
Main mass:DPitt
Comments:Field name MCVICH030; submitted by C. Agee, UNM
Plots: O isotopes:  
Institutions
   and collections		 UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
Find references in NASA ADS:
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Geography:

Mauritania
Coordinates:Unknown.

Statistics:
     This is 1 of 195 approved meteorites from Mauritania (plus 1 unapproved name) (plus 2 impact craters)

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