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Northwest Africa 10785
Basic information Name: Northwest Africa 10785
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10785
Observed fall: No
Year found: 2015
Country: (Northwest Africa)
Mass:help 71.7 g
Classification
  history:
Meteoritical Bulletin:  MB 105  (2016)  Achondrite-ung
Recommended:  Achondrite-ung    [explanation]

This is 1 of 99 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 2 Nov 2016
Writeuphelp
Writeup from MB 105:

Northwest Africa 10785 (NWA 10785)

(Northwest Africa)

Purchased: 2015 May 1

Classification: Ungrouped achondrite

History: Purchased in Agadir, with no details on provenance.

Physical characteristics: A half-stone covered by fusion crust, with 2 cm yellow blocks in a whitish matrix. Recognized as similar to NWA 7835 by L. Labenne.

Petrography: (R. Hewins, S. Pont, B. Zanda, MNHNP) The dominant minerals are olivine and orthopyroxene, in a polished section that shows a blocky zone and a pseudo-porphyritic zone. Olivine grains in the blocky zone are at least 6 mm in maximum dimension, and are separated by patches and sparse veinlets of mesostasis. Olivine-orthopyroxene contacts are irregular, often with plagioclase (glass?) separating the two phases, with olivine-rich veinlets invading the pyroxene. Outside the blocky zone, angular grains of olivine and orthopyroxene are supported in a mesostasis with 10-20 μm roundish granules of orthopyroxene embedded in plagioclase probably glass. Minor minerals in the mesostasis are augite, chromite, taenite and troilite.

Geochemistry: Mineral compositions and Geochemistry: (R. Hewins, S. Pont, MNHNP and J.-A. Barrat, UBrest) The olivine is Fa26.1±0.4, with FeO/MnO 53.8±3.4. The orthopyroxene composition is En77.5±1.1Fs21.0±0.7Wo1.6±0.4, with Fe/Mn atomic ratio 38.9±3.3. "Plagioclase" is An15.1±1.1Ab80.6±0.6Or4.3±0.7. These compositions are almost identical to those of NWA 7835 (Irving et al., 2014), though differences in the descriptions of the textures might mean different thermal history. Taenite contains ~37% Ni.

Classification: (R. Hewins MNHN, L. Labenne, Paris) (Harzburgitic) ungrouped achondrite. Possibly paired with NWA 7835.

Specimens: The main mass (57 g) is held by Labenne. The type specimen of 10.87 g and 3.74 g is at MNHNP.

Data from:
  MB105
  Table 0
  Line 0:
Place of purchase:Agadir
Date:P 2015 May 1
Mass (g):71.7
Pieces:1
Class:Achondrite-ung
Weathering grade:low
Classifier:R. Hewins, MNHNP
Type spec mass (g):14.61
Type spec location:MNHNP
Main mass:Labenne Meteorites
Comments:Z: Temporary name LM 220515 Z.; submitted by R. Hewins
Institutions
   and collections
MNHNP: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address)
Labenne: 23, rue de Esperance, 75013 Paris, France; Website (private address; updated 29 Aug 2012)
MNHN: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address)
UBrest: Université de Bretagne Occidentale 3 Rue des Archives, 29238 Brest, France (institutional address; updated 2 Nov 2016)
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: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7374 approved meteorites from (Northwest Africa) (plus 1957 unapproved names)

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