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Northwest Africa 14790
Basic information Name: Northwest Africa 14790
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14790
Observed fall: No
Year found: 2012
Country: Morocco
Mass:help 402 g
Recommended:  L6    [explanation]

This is 1 of 12189 approved meteorites (plus 7 unapproved names) classified as L6.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 26 Mar 2022
Writeup from MB 111:

Northwest Africa 14790 (NWA 14790)


Purchased: 2012

Classification: Ordinary chondrite (L6)

History: Sample was purchased in 2012 from Adam Aaronson at the Tucson mineral show who acquired it from Morocco. Sample is catalogued at ROM as M58212.

Physical characteristics: A single, weathered individual with minor remnants of fusion crust, and well-developed desert polish. Broken surfaces are knobby mm-sized chondrule sockets and chondrules standing out in relief. Physical properties: Magnetic susceptibility measured for a 8.11 g slice is log χ (× 10-9 m3/kg) = 3.88.

Petrography: Cut face (17 cm2) shows a dun brown fine grained interior, hosting widely spaced dark chondrules that are poorly discerned. A few mm-sized metal grains are present. A 0.5 mm thick shock vein cuts across the cut surface. In polished thin section, an anastamosing shock vein consists of dark, turbid material and ranges 100-500 µm in thickness, with sharp contacts with the host chondrite. The vein locally contains a rounded mm size metal grain. The host chondrite is highly fractured, with olivine typically showing mosaic extinction. Chondrules are barely discernable, in a coarsely recrystallized matrix that has visible porosity. Metal and sulfide grains are extensively replaced by Fe oxides, and siliactes in the section show pervasive Fe staining. In BSE images, olivine, two pyroxenes and interstitial feldspathic material typically show simplified, recrystallized grain boundaries. Feldspathic material is featureless grey in BSE and in thin section appears isotropic black in cross-polarized light.

Geochemistry: EPMA: Olivine Fa24.95±0.16 (n=30); Ca-poor pyroxene Fs20.73±0.41Wo2.63±0.79 (n=21); Ca-rich pyroxene Wo36.37±1.20Fs11.87±1.37 (n=9).

Classification: Ordinary chondrite: L6 (S5) W3. EPMA compositions for olivine and pyroxene grains are consistent with L6 classification. Extensive breakdown of metal and sulfide grains to Fe oxides and porosity seen in matrix suggests weathering W3, supported by the low magnetic susceptibility, below typical values for L chondrites.

Specimens: Type specimen location: ROM. Main mass: D. Gregory.

Data from:
  Table 0
  Line 0:
Place of purchase:Tucson, AZ, USA
Date:P 2012
Mass (g):402.33
Shock stage:S5
Weathering grade:W3
Fayalite (mol%):24.95±0.16
Ferrosilite (mol%):20.73±0.41
Wollastonite (mol%):2.63±0.79
Magnetic suscept.:3.88
Classifier:P. McCausland, ROM, UWO
Type spec mass (g):21.46
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)
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)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
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 1902 approved meteorites from Morocco (plus 27 unapproved names) (plus 1 impact crater)

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