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Northwest Africa 7755 | |||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 7755 This is an OFFICIAL meteorite name. Abbreviation: NWA 7755 Observed fall: No Year found: 2013 Country: Morocco Mass: ![]() | ||||||||||||||||||||||||||
Classification history: |
This is 1 of 307 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||||||
Comments: | Approved 27 Mar 2013 | ||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 102:
Northwest Africa 7755 (NWA 7755) Morocco Purchased: 2013 Classification: Martian meteorite (Shergottite) History: Purchased by Matt Morgan and Lee Morgan in 2013 from a Moroccan meteorite dealer. Physical characteristics: Single stone with black glassy fusion crust, with some light-colored desert sediment coating. A saw cut reveals poikilitic texture. Petrography: (C. Agee, UNM) Microprobe examination of a polished epoxy mount shows ~45% olivine, ~35% pyroxene, ~20% maskelynite, ubiquitous Cr-Ti-Fe oxides. Pyroxenes and olivines are highly equilibrated, with no zonation in BSE images, heavily shocked, grain size ranges from 200-1000 μm. Geochemistry: (C. Agee and L. Burkemper, UNM) EMPA. Olivine Fa38.5±0.8, Fe/Mn=48±2, n=38; pigeonite Fs29.4±1.5Wo10.4±2.4, Fe/Mn=28±1, n=33; augite Fs18.2±1.2Wo34.2±2.4, Fe/Mn=26±2, n=7; maskelynite Or2.3±0.3Ab46.0±2.3An51.6±2.4 N=20. Oxygen Isotopes, laser fluorination (K. Ziegler, UNM), analyses on 3 acid-washed aliquots, 1.5, 1.4, 1.0 mg, gave values δ17O=2.988, 2.882, 2.735; δ18O=5.188, 4.886, 4.696; Δ17O=0.249, 0.302, 0.256 (linearized, all permil). Classification: Achondrite (Martian, shergottite), petrologically equilibrated ultramafic rock, poikilitic shergottite group, with relatively high modal maskelynite, but lacking pyroxene crystallization trends seen in olivine-phyric basaltic shergottites. No known pairings, but pyroxene and olivine compositions are similar to RBT 04262. Specimens: 6 g including microprobe mount on deposit UNM, Matt Morgan holds the main mass. | ||||||||||||||||||||||||||
Data from: MB102 Table 0 Line 0: |
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Plots: | O isotopes: | ||||||||||||||||||||||||||
Institutions and collections |
UNM: Institute of Meteoritics
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
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Photos: |
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Geography:![]() |
Statistics: This is 1 of 2012 approved meteorites from Morocco (plus 35 unapproved names) (plus 1 impact crater) |