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Northwest Africa 7988
Basic information Name: Northwest Africa 7988
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7988
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 116 g
Classification
  history:
Meteoritical Bulletin:  MB 103  (2014)  LL6
Recommended:  LL6    [explanation]

This is 1 of 2740 approved meteorites (plus 1 unapproved name) classified as LL6.   [show all]
Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 23 Jun 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 7988 (NWA 7988)

(Northwest Africa)

Purchased: 2013 Jul

Classification: Ordinary chondrite (LL6)

History: Purchased by M. Ouzillou in July 2013 from a dealer in Zagora, Morocco.

Physical characteristics: Very fresh specimen (116 g) with partial black fusion crust composed of darker gray clasts (up to 1.1 cm across) in a lighter gray matrix. Minor terrestrial staining of sulfides locally present.

Petrography: (A. Irving and S. Kuehner, UWS; M. Zolensky, JSC) Fresh, highly recrystallized breccia. A single identifiable chondrule was found within the thin section. Composed of olivine, clinopyroxene, orthopyroxene, sodic plagioclase, troilite, unaltered Ni-rich metal (taenite) and Ti-bearing chromite (rimmed by ilmenite). Troilite and Ni-rich metal commonly form composite grains, but no kamacite is present.

Geochemistry: Olivine (Fa32.0-32.1; FeO/MnO = 60-61), orthopyroxene (Fs24.1-25.5Wo1.7-1.9), clinopyroxene (Fs10.4Wo43.2), metal (Ni 61.0 wt.%, Fe 37.1 wt.%, Co 1.0 wt.%). Oxygen isotopes (K. Ziegler, UNM) Analyses of acid-washed subsamples by laser fluorination gave, respectively (all in per mil) δ17O = 3.765, 3.873; δ18O = 4.914, 5.155; Δ17O = 1.170, 1.151 (for a TFL slope of 0.528).

Classification: Ordinary chondrite (LL6). The major mineral compositions and oxygen isotopes are consistent with an LL chondrite affinity, but the complete lack of kamacite, abundance of troilite, very Ni-rich taenite, and the Ti-rich chromite + ilmenite assemblage are rare features in comparison with typical LL chondrites.

Specimens: 21 g and one polished thin section are at UWB. The remainder is held by Mr. M. Ouzillou.

Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Zagora
Date:P 2013 Jul
Mass (g):116
Pieces:1
Class:LL6
Shock stage:S2
Weathering grade:W0/1
Fayalite (mol%):32.0-32.1
Ferrosilite (mol%):24.1-25.5
Wollastonite (mol%):1.2-1.3
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):21
Type spec location:UWB
Main mass:M. Ouzillou
Comments:38.12; submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
JSC: Mailcode KT, 2101 NASA Parkway, NASA Johnson Space Center, Houston, TX 77058, United States; Website (institutional address; updated 3 Sep 2013)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
Find references in NASA ADS:
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Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6758 approved meteorites from (Northwest Africa) (plus 2048 unapproved names)

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