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Northwest Africa 14635
Basic information Name: Northwest Africa 14635
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14635
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 72 g
Classification
  history:
Recommended:  Achondrite (brachinite-like)    [explanation]

This is 1 of 2 approved meteorites classified as Achondrite (brachinite-like).   [show all]
Search for other: Primitive achondrites, Ungrouped achondrites
Comments: Approved 26 Mar 2022
Writeuphelp
Writeup from MB 111:

Northwest Africa 14635 (NWA 14635)

(Northwest Africa)

Purchased: 2009

Classification: Brachinite-like achondrite

History: Purchased by Chalom Malka in 2009 from a meteorite dealer in Morocco.

Physical characteristics: Three stones with weathered fusion crust.

Petrography: (D. Sheikh, Cascadia) Sample displays a protogranular texture (Av. grain size=360±230 μm, n=253) predominantly composed of olivine (some grains are elongated and display a notable alignment) (~81 vol. %), orthopyroxene (some regions of the sample display orthopyroxene poikilitically enclosing olivine, chromite, and accessory plagioclase) (~15 vol. %), augite (~3 vol. %), chromite (~1 vol. %), and accessory plagioclase (observed only poikilitically enclosed within either orthopyroxene or chromite), troilite, chlorapatite, merrillite, and Fe-Ni metal (some altered to Fe-hydroxides). A fine-grained intergrowth of orthopyroxene + opaque minerals is observed along the margins of some olivine grains.

Geochemistry: Olivine (Fa28.0±0.7, range Fa26.7-29.0, CaO=<0.1 wt. %, Cr2O3=<0.1 wt. %, Fe/Mg=0.39±0.01, Fe/Mn=54±2, n=17), Orthopyroxene (Fs23.9±1.5Wo1.9±0.5, range Fs20.5-24.7Wo0.8-2.2, Fe/Mn=36±3, n=13), Augite (Fs9.8±0.1Wo43.5±0.1, range Fs9.7-9.8Wo43.4-43.5, Al2O3=0.7±0.1 wt. %, Cr2O3=0.9±0.1 wt. %, Fe/Mn=25±2, n=2), Plagioclase (An35.2±0.8Or1.1±0.1, range An34.4-35.7Or1.1-1.2, n=3), Chromite (Cr#=76.1±0.1, Mg#=23.9±2.4, TiO2=1.3±0.1 wt. %, n=5).

Classification: Achondrite (brachinite-like). While the overall texture, mineralogy, and mineral compositions of the sample are similar to brachinites, the high modal abundance of orthopyroxene, the presence of poikilitic pyroxene-rich areas, the near absence of plagioclase feldspar observed in the sample, the low abundance of CaO in olivine, the low Fe/Mg-Fe/Mn molar ratios of olivine, the fine-grained intergrowth of orthopyroxene + opaque minerals observed at olivine grain boundaries, and the more magnesian compositions of olivine and orthopyroxene indicate that this sample is representative of a brachinite-like achondrite (Goodrich et al., 2017), having similarities to NWA 595, NWA 1500, and NWA 5400.

Specimens: 14.5 g at Cascadia, main mass with Chalom Malka

Bibliography:
  • Goodrich C. A., Kita N. T., Sutton S. R., Wirick S. and Gross J. (2017) The Miller Range 090340 and 090206 meteorites: Identification of new brachinite-like achondrites with implications for the diversity and petrogenesis of the brachinite clan. Meteoritics & Planetary Science 52, 949–978. (link)
Data from:
  MB111
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2009
Mass (g):72
Pieces:3
Class:Achondrite (brachinite-like)
Shock stage:low
Weathering grade:moderate
Fayalite (mol%):28.0±0.7
Ferrosilite (mol%):23.9±1.5, 9.8±0.1
Wollastonite (mol%):1.9±0.5, 43.5±0.1
Classifier:D. Sheikh, Cascadia
Type spec mass (g):14.5
Type spec location:Cascadia
Main mass:Chalom Malka
Comments:CML 1493; 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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Daniel Sheikh      
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8674 approved meteorites from (Northwest Africa) (plus 1882 unapproved names)

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