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Northwest Africa 12955
Basic information Name: Northwest Africa 12955
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12955
Observed fall: No
Year found: 2016
Country: Algeria
Mass:help 38.6 g
Classification
  history:
Recommended:  Eucrite-pmict    [explanation]

This is 1 of 344 approved meteorites classified as Eucrite-pmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 23 Dec 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12955 (NWA 12955)

Algeria

Find: 2016

Classification: HED achondrite (Eucrite, polymict)

History: Purchased in 2016 in Morocco by Matthew Stream from Daoud Wabich.

Physical characteristics: Single stone with minor fusion crust. A slice of the interior reveals an assortment of light and dark clasts.

Petrography: (D. Sheikh, FSU) Sample is a breccia composed predominantly of cumulate and basaltic eucritic clasts (>5mm) set in a dark fine-grained matrix containing isolated mineral fragments (>3mm). Some diogenitic clasts are present as well (<10% volume). Minerals present include orthopyroxene, pigeonite, augite, calcic plagioclase, chromite (some containing Ti), iron-rich olivine, ilmenite, silica polymorph, troilite, FeNi metal, and barite. Some of the pyroxenes exhibit exsolution textures. Some carbonate weathering veins are present.

Geochemistry: Low-Ca pyroxene (Fs39.3±2.4 Wo3.5±1.4, Fe/Mn=29, n=12; Fs57.6±3.2 Wo4.2±1.1, Fe/Mn=30, n=30), diogenitic orthopyroxene (Fs26.7±1.9 Wo2.6±0.7, Fe/Mn=30, n=22), pigeonite (Fs51.6±6.8 Wo9.7±3.1, Fe/Mn=31, n=27), augite (Fs28.5±3.2 Wo41.1±1.2, Fe/Mn=30, n=18), low-Ca pyroxene host (Fs57.0±0.4 Wo5.3±0.4, Fe/Mn=31, n=12), high-Ca pyroxene exsolution lamellae (Fs36.7±2.1 Wo28.8±2.5, Fe/Mn=28, n=9), calcic plagioclase (An90.5±2.0 Or0.3±0.1, n=19), olivine (Fa64.7±1.6, Fe/Mn=46,n=3), chromite (Cr/(Cr+Al)=82, n=2), ilmenite (Fe/(Fe+Mg)=92, n=2).

Classification: Eucrite (polymict breccia)

Specimens: 9.06 grams at UCLA; main mass with Matthew Stream.

Data from:
  MB108
  Table 0
  Line 0:
Date:2016
Mass (g):38.57
Pieces:1
Class:Eucrite-pmict
Shock stage:moderate
Weathering grade:moderate
Classifier:D. Sheikh, FSU
Type spec mass (g):9.06
Type spec location:UCLA
Main mass:Matthew Stream
Comments:Submitted by Daniel Sheikh
Institutions
   and collections
UCLA: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, United States (institutional address; updated 17 Oct 2011)
FSU: Department of Geological Sciences, Florida State University, Tallahassee FL 32306-4100, United States (institutional address; updated 16 Dec 2010)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Daniel Sheikh   
Geography:

Algeria
Coordinates:Unknown.

Statistics:
     This is 1 of 983 approved meteorites from Algeria (plus 26 unapproved names) (plus 4 impact craters)

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