|Northwest Africa 7397|
|Basic information||Name: Northwest Africa 7397|
This is an OFFICIAL meteorite name.
Abbreviation: NWA 7397
Observed fall: No
Year found: 2012
Country: (Northwest Africa)
Mass: 2.13 kg
This is 1 of 141 approved meteorites (plus 1 unapproved name) classified as Martian (shergottite). [show all]
Search for other: Martian meteorites
|Comments:||Approved 1 Jan 2013|
Writeup from MB 102:
Northwest Africa 7397 (NWA 7397)
Purchased: 2012 Jun
Classification: Martian meteorite (Shergottite)
History: Found near Smara, Morocco and purchased by Darryl Pitt and David Gheesling from a dealer in Zagora, Morocco in 2012 June.
Physical characteristics: A 2130 g, partially covered in fusion crust. Interior larger ovoid crystals in a finer grained matrix.
Petrography: (A. Irving and S. Kuehner, UWS) Large oikocrysts (up to 1.5 cm across) of low-Ca pyroxene enclose multiple chadacrysts of olivine and Cr-rich chromite. Relatively equigranular domains between oikocrysts are composed of low-Ca and high-Ca pyroxene (showing very limited compositional zoning), maskleynite and olivine with accessory merrillite, Ti-chromite, pyrrhotite and ilmenite (with associated grains of baddeleyite up to 10 μm across). Olivine contains sparse melt inclusions composed of K-Na-Al-Si-rich glass surrounded by characteristic post-shock radial expansion microfractures.
Geochemistry: Olivine (Fa38.9-40.7; FeO/MnO = 47-54), orthopyroxene (Fs30.3Wo3.3; FeO/MnO = 36), pigeonite (Fs25.1-27.6Wo6.6-10.0; FeO/MnO = 28-33), subcalcic augite (Fs17.0-19.0Wo35.1-35.4; FeO/MnO = 22-25). Bulk trace element composition (G. Chen, UAb): analysis by ICP-MS of clean wire-saw cutting dust gave (in ppm) La 1.66, Ce 4.48, Nd 2.93, Sm 1.13, Eu 0.3, Gd 1.59, Dy 1.95, Yb 1.02, Lu 0.14, Hf 1.66, Th 1.15, Rb 2.89, Sr 33.6.
Classification: Martian (shergottite, poikilitic).
Specimens: A total of 20 g of type material and one large polished thin section are on deposit at UWB. The main mass is held jointly by DPitt and D. Gheesling.
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
|References:||Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015|
This is 1 of 5322 approved meteorites from (Northwest Africa) (plus 2131 unapproved names)
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