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Northwest Africa 7755
Basic information Name: Northwest Africa 7755
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7755
Observed fall: No
Year found: 2013
Country: Morocco
Mass:help 30 g
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  Martian (shergottite)
Recommended:  Martian (shergottite)    [explanation]

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
Writeuphelp
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:
Place of purchase:Morocco
Date:P 2013
Mass (g):30
Pieces:1
Class:Martian (shergottite)
Fayalite (mol%):38.5±0.8
Ferrosilite (mol%):29.4±1.5, 18.2±1.2
Wollastonite (mol%):10.4±2.4, 34.2±2.4
Classifier:C. Agee, UNM
Type spec mass (g):6
Type spec location:UNM
Main mass:Matt Morgan
Comments:Submitted by C. Agee
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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
John A. Shea   
Geography:

Morocco
Coordinates:Unknown.

Statistics:
     This is 1 of 2012 approved meteorites from Morocco (plus 35 unapproved names) (plus 1 impact crater)

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