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Northwest Africa 720
Basic information Name: Northwest Africa 720
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 720
Observed fall: No
Year found: 2001
Country: Morocco
Mass:help 118.7 g
Recommended:  LL6    [explanation]

This is 1 of 2857 approved meteorites (plus 2 unapproved names) 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 8 May 2022
Writeup from MB 111:

Northwest Africa 720 (NWA 720)


Purchased: 2001

Classification: Ordinary chondrite (LL6)

History: Sample origin Boudnib, purchased Alnif in Jan 2001. Provisional 23.1 g sample at UCLA. Type sample is catalogued at the ROM as M52971.

Physical characteristics: Blocky individual with two generations of fusion crust, ranging from smooth curved to sub-cm regmalypted, implying that this stone is a fragment from a larger fall. Broken surfaces (40%) and fusion crust surfaces show mature desert polish. Physical properties: Magnetic susceptibilty of a 2.18 g specimen is log χ (× 10-9 m3/kg) = 4.03.

Petrography: Cut face (10 cm2) shows a green stone with dark, irregular cm wide veins of fine grained material. Metal is sparse, with associated local Fe oxides. Dark veins have associated Fe oxide staining but are generally devoid of visible metal grains. In polished thin section, chondrules are poorly delineated in a coarsely recrystallized matrix. A representative dark 8 mm wide vein cuts the chondrite with sharp contacts and contains fragments of large chondrules, lithic chondritic clasts and finer chondritic debris. Metal grains up to 400 µm in the host chondrite show embayed texture on silicates; metal grains are much smaller in the dark vein. Sulfides are abundant and finely disseminated in both chondritic host and vein. Shock veins up to 30 µm width partly defined by sulfide fill cross cut and offset the chondritic host and dark vein material. Olivine and pyroxene typically show undulatory to mosaic extinction.

Classification: Ordinary chondrite LL6 (S4) W2. Low observed metal content and magnetic susceptibility are consistent with LL chondrite. Stone appears to be an LL6 breccia with dark veins of fragmental material that subsequently developed shock veins.

Specimens: Type specimen ROM; main mass Gregory

Data from:
  Table 0
  Line 0:
Place of purchase:Alnif
Date:P 2001
Mass (g):118.69
Shock stage:S4
Weathering grade:W2
Magnetic suscept.:4.03
Classifier:P. McCausland (ROM, UWO), V Di Cecco (ROM)
Type spec mass (g):23.71
Type spec location:ROM
Main mass:DGregory
Comments:Submitted by V. Di Cecco, ROM
   and collections
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011)
UCLA: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, United States (institutional address; updated 17 Oct 2011)
UWO: University of Western Ontario, Department of Earth Sciences, BGS 1026, 1151 Richmond St. N, London, Ontario, Canada N6A 5B7, Canada (institutional address; updated 18 Jul 2015)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
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     This is 1 of 1887 approved meteorites from Morocco (plus 26 unapproved names) (plus 1 impact crater)

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