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Northwest Africa 5782
Basic information Name: Northwest Africa 5782
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 5782
Observed fall: No
Year found: unknown
Country: Morocco
Mass:help 130 g
Meteoritical Bulletin:  MB 97  (2010)  Acapulcoite (anom)
Recommended:  Acapulcoite/lodranite    [explanation]

This is 1 of 11 approved meteorites classified as Acapulcoite/lodranite.   [show all]
Search for other: Acapulcoite-lodranite family, Primitive achondrites
Comments: Approved 17 Dec 2009
Writeup from MB 97:

Northwest Africa 5782


Found: Purchased: September 2008

Classification: Achondrite (acapulcoite/lodranite)

History and physical characteristics: Purchased by Blaine Reed at the Denver Mineral Show. Two pieces with a total mass of 130 g were found in a batch of meteorites. The stones experienced moderate terrestrial weathering, but some fusion crust is still visible.

Petrography: (T. Bunch and J. Wittke, NAU; A. Irving, UWS; P. Sipiera, PSF): A polymict breccia of subrounded to subangular clasts (exhibiting some preferred orientation) set in a cataclastic matrix with minor glass and secondary Fe hydroxide veinlets (Fig. 3). The most abundant clasts (45 vol%) are recrystallized acapulcoites with polygonal texture (mean grain size is 0.225 mm). Coarser grained, protogranular to polygonal textured clasts (25 vol%) are various types of lodranites (mean grain size is 0.745). The matrix (30 vol%) contains debris from both types of lithology, and additionally rare, small xenolithic fragments of augite with exsolution lamellae of Ca-poor pyroxene.

Mineral compositions and geochemistry: Acapulcoites Olivine Fa8.7–13.3 (FeO⁄MnO = 17–27); low-Ca pyroxene Fs9.0–4.1, Wo2.1–3.0; clinopyroxene Fs4.8–7.5, Wo45.7–47.9. Lodranites Olivine Fa8.6–13.7 (FeO⁄MnO = 16–18); low-Ca pyroxene Fs12.7–13.7, Wo2.8; clinopyroxene Fs4.6, Wo46.7 (Al2O3 1.10 wt%, Cr2O3 1.83 wt%, TiO2 0.63 wt%). Xenolithic fragment clinopyroxene Fs19.5, Wo42.8 (FeO⁄MnO = 24); orthopyroxene Fs40.7Wo4.1 (FeO⁄MnO = 32). Oxygen isotopes (D. Rumble, CIW): acid-washed material analyzed in duplicate by laser fluorination gave, respectively δ17O = 0.53, 0.66; δ18O = 3.24, 3.03; Δ17O = -1.172, -0.936 per mil.

Classification: Achondrite (acapulcoite, anomalous). This specimen is unusual among acapulcoites in that it is a breccia and contains a significant component of lodranite clasts.

Specimens: A total of 20.8 g of material and one polished thin section are on deposit at FMNH in the PSF collection; another thin section is on deposit at NAU. The main mass is held by B. Reed.

Data from:
  Table 1
  Line 261:
Place of purchase:Denver Mineral Show
Date:September 2008
Mass (g):130
Class:Acapulcoite (anom)
Ferrosilite (mol%):8.7-13.3
Wollastonite (mol%):Fs9.0-14.1
Classifier:Bunch and Wittke, NAU
Type spec mass (g):20.8
Type spec location:NAU
Main mass:Reed
Comments:Polymict breccia, see written description
Plots: O isotopes:  
   and collections
FMNH: NW Quadrant/Geology The Field Museum of Natural History 1400 South Lake Shore Drive Chicago, IL 60605-2496, USA, United States; Website (institutional address; updated 22 May 2024)
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
PSF: Planetary Studies Foundation,10 Winterwood Lane, Unit B, Galena, Illinois 61036-9283, United States; Website (institutional address; updated 1 Dec 2011)
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)
Reed: Blaine Reed, P.O. Box 1141, Delta, CO 81416, United States; Website (private address)
References: Published in Meteoritical Bulletin, no. 97, MAPS 45, 449-493 (2010)
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     This is 1 of 2089 approved meteorites from Morocco (plus 32 unapproved names) (plus 1 impact crater)

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