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Northwest Africa 7870
Basic information Name: Northwest Africa 7870
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7870
Observed fall: No
Year found: 2004
Country: (Northwest Africa)
Mass:help 42 g
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  L4
Recommended:  L4    [explanation]

This is 1 of 1709 approved meteorites (plus 4 unapproved names) classified as L4.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 9 May 2013
Writeuphelp
Writeup from MB 102:

Northwest Africa 7870 (NWA 7870)

(Northwest Africa)

Purchased: Feb 2004

Classification: Ordinary chondrite (L4)

History: The rock was obtained by Edwin Thompson from a Moroccan trader at the Tucson Gem and Mineral Show and a portion was donated to Cascadia in February 2004.

Physical characteristics: The rock has a grey and pitted/bumpy exterior, and appears grey in cut faces.

Petrography: (K. Armstrong and A. Ruzicka, Cascadia) The specimen shows chondritic texture with readily discernible chondrules (mean diameter = 0.5 ± 0.3 mm) and matrix that appears translucent in transmitted light. The abundance of metal and troilite as determined by pixel counting in reflected light images is 3.1±0.1 and 3.5±0.7 area%, respectively.

Geochemistry: Olivine Fa25.3±1.2 Fe/Mn=47.4±6.5 (N=36) and low-Ca pyroxene Wo1.6±0.2 Fs16.2±6.4 Fe/Mn = 25.3±6.9 (N=25).

Classification: Mineral chemistry, chondrule sizes, and metal abundance are most consistent with an L4 chondrite.

Specimens: 14.6 g in two pieces and a polished thin section are on deposit at CascadiaThompson holds the main mass.

Data from:
  MB102
  Table 0
  Line 0:
Place of purchase:Tuscon, Arizona
Date:P Feb 2004
Mass (g):42
Pieces:1
Class:L4
Shock stage:S4
Weathering grade:W1
Fayalite (mol%):25.3±1.2
Ferrosilite (mol%):16.2±6.4
Wollastonite (mol%):1.6±0.2
Classifier:K. Armstrong and A. Ruzicka , Cascadia
Type spec mass (g):14.6
Type spec location:Cascadia
Main mass:Edwin Thompson
Comments:Lab Sample CML0173; submitted by A. Ruzicka
Institutions
   and collections
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
Thompson: Edwin Thompson, 5150 Dawn St., Lake Oswego, OR 97035, United States (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7579 approved meteorites from (Northwest Africa) (plus 1969 unapproved names)

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