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Northwest Africa 11880
Basic information Name: Northwest Africa 11880
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11880
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 32.9 g
Classification
  history:
Recommended:  R3.5-4    [explanation]

This is 1 of 2 approved meteorites classified as R3.5-4.   [show all]
Search for other: Rumuruti chondrites, Rumuruti chondrites (type 3)
Comments: Approved 17 Jul 2018
Writeuphelp
Writeup from MB 107:

Northwest Africa 11880 (NWA 11880)

Northwest Africa

Purchased: 2018 Jan

Classification: Rumuruti chondrite (R3.5-4)

Petrography: The sample is a breccia, consisting of light and dark clasts. The light clasts display well-defined chondrules surrounded by a fine-grained matrix. The dark clasts show very well-defined chondrules in a dark and glassy matrix. Mean apparent chondrule size is 550±377 μm in the dark clasts, and 694±316 μm in the light clasts. Maximum chondrule size is 2.65 mm. Undulatory extinction is visible in olivine grains. No oxidation rims are seen on sulphides or metal grains.

Geochemistry: As determined by EPMA, Dark Clast olivine compositions are: Fa=31.3±27.6 (n=35), coefficient of variation CV%=43.7, Cr2O3 (wt%) = 0.14. Dark clast pyroxene compositions are: High Ca Pyroxene - Fs18.2±5.5En52.5±7.3Wo29.2±12 (n=4), Low Ca Pyroxene - Fs29.6±5.6En66.2±1.2Wo4.2±5.1, (n=5). Light Clast olivine compositions are: Fa40.9±0.6 (n=10), CV%=1.1, Cr2O3 (wt%) = 0.08. Light clast pyroxene compositions are: Fs13.7±3.4En43.9±0.7Wo42.4±4.0 (n=6) (V. Di Cecco, ROM)

Classification: Pyroxenes: Dark/Unequilibrated Clast - High and low Ca pyroxenes occur in roughly equal proportions. Light/Equilibrated Clast - Ca pyroxene is dominant. This follows the summary of Bischoff et al. (2011) for R chondrites. Fa40.9±0.6 is consistent with reported composition of equilibrated R chondrites. CV% of 43.7 suggests petrologic type 3.5.

Bibliography:
  • A. Bischoff, N. Vogel, and J. Roszjar (2011) The Rumuruti chondrite group. Chemie der Erde 71, 101-133. (link)
Data from:
  MB107
  Table 0
  Line 0:
Place of purchase:Tucson Gem and Mineral Show
Date:P 2018 Jan
Mass (g):32.87
Pieces:1
Class:R3.5-4
Shock stage:S2
Weathering grade:W0
Fayalite (mol%):8.3-43.1
Ferrosilite (mol%):10.5-33.8
Wollastonite (mol%):1.1-46.3
Classifier:V. Di Cecco, ROM
Type spec mass (g):32.87
Type spec location:ROM
Main mass:ROM
Comments:Sample registered at ROM as M58493; submitted by V. Di Cecco, ROM
Institutions
   and collections
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 107, in preparation (2018)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6758 approved meteorites from (Northwest Africa) (plus 2048 unapproved names)

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