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Northwest Africa 2400
Basic information Name: Northwest Africa 2400
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2400
Observed fall: No
Year found: 2003
Country: (Northwest Africa)
Mass:help 136 g
Meteoritical Bulletin:  MB 89  (2005)  Achondrite-ung
MetBase:  v. 7.1  (2006)  Achondrite-ung
Recommended:  Achondrite-ung    [explanation]

This is 1 of 84 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Writeup from MB 89:

Northwest Africa 2400

Morocco or Algeria

Purchased 2003 April

Achondrite (ungrouped)

A 137 g light tan to rusty brown, fully crusted stone was purchased in Rissani, Morocco in April 2003. Description and classification (T. Bunch and J. Wittke, NAU; A. Irving and S. Kuehner, UWS): composed mainly of approximately mm-sized, randomly oriented pigeonite (Fs64-64.8Wo5.6-6.4) with very fine, parallel exsolution lamellae of augite (Fs38-49.1Wo36.7-23), and interstitial, recrystallized plagioclase (<0.10 mm in size, ~An86Or0.5) with prominent triple junctions, and rare, unrecrystallized, tabular plagioclase relicts (<1 mm, zoned from An80to An89). FeO/MnO ratios for all pyroxenes range from 59.5 to 68.7 (avg. 64.7). Only small amounts of pyroxene are present in the recrystallized zones. Accessory minerals occurring predominantly in the recrystallized plagioclase zones include a silica polymorph, chromite [Cr/(Cr + Al) = 83, Fe/(Fe + Mg) = 67], ilmenite (53.5 wt. % TiO2, 43.6 wt. % FeO; with small baddeleyite inclusions), merrillite (some with minor amounts of Na2O, MgO, and FeO), Zn-bearing troilite, pentlandite, Cr-ulvöspinel and altered Fe metal (associated with minor troilite, barite and calcite). Shock damage is not apparent and, with the exception of the oxidation of minor metal, weathering effects are very low. Oxygen isotopes (D. Rumble, CIW): replicate analyses by laser fluorination gave δ17O = - 0.15 ± 0.1, δ18O = 3.27 ± 0.2, Δ17O = -1.57 ± 0.03 per mil. In its texture, mineral mode, mineral compositions and oxygen isotope composition NWA 2400 is nearly identical to the anomalous achondrite NWA 011 (Yamaguchi et al., 2002; Promprated et al., 2003), which strongly indicates that these two stones are paired. Specimens: type specimen 20.2 g and three polished thin sections, NAU; main mass, anonymous purchaser.

Data from:
  Table 7
  Line 240:
Place of purchase:Erfoud
Mass (g):136
Classifier:Ted Bunch, NAU
Type spec mass (g):20.2
Type spec location:NAU
Plots: O isotopes:  
   and collections
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
References: Published in Meteoritical Bulletin, no. 89, MAPS 40, A201-A263 (2005)
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Christophe PICQ   
Mohammed HMANI      

     This is 1 of 6759 approved meteorites from (Northwest Africa) (plus 2047 unapproved names)

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