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Northwest Africa 10311
Basic information Name: Northwest Africa 10311
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10311
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 184 g
Meteoritical Bulletin:  MB 104  (2015)  H5
Recommended:  H5    [explanation]

This is 1 of 11764 approved meteorites (plus 23 unapproved names) classified as H5.   [show all]
Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 15 Sep 2015
Writeup from MB 104:

Northwest Africa 10311 (NWA 10311)

(Northwest Africa)

Purchased: April 2013

Classification: Ordinary chondrite (H5)

History: Purchased online in 2013 by John A. Shea as an NWA meteorite and a portion subsequently donated to Cascadia.

Physical characteristics: Already cut piece shows well-developed fusion crust on external surfaces. Cut faces show chondritic texture with high metal content and significant reddish staining.

Petrography: (M. Ream and A. Ruzicka, Cascadia) Chondrules can be readily distinguished from the moderately coarse-grained matrix. Mean chondrule diameter is (N = 29) 0.8±0.2 mm. Sample contains ~10% metal and ~8% troilite. The olivine is mosaicized and most grains show 2 planar fracture sets, indicating a shock stage S4. Cl-apatite and merrillite (~70–150 μm) are present. Feldspar grain sizes are typically ~50 µm or less.

Geochemistry: Olivine, Fa19.5±0.4 (Fa1.9–20.6, N = 15); low-Ca pyroxene, Fs17.1±0.3Wo 1.6±0.2 (Fs16.8–17.9Wo1.2–1.9, N = 12); feldspar Ab9.6±0.6Or6.2±0.5 (Ab78.9–80.2Or5.9–6.9, N = 4)

Classification: High metal content and mineral compositions suggests an H chondrite, and feldspar grain sizes suggest a petrologic type 5.

Specimens: Cascadia holds 46.2 g and polished thin section. John Shea holds the main mass.

Data from:
  Table 0
  Line 0:
Date:P April 2013
Mass (g):184
Shock stage:S4
Weathering grade:W1
Fayalite (mol%):19.5±0.4
Ferrosilite (mol%):17.1±0.3
Wollastonite (mol%):1.6±0.2
Classifier:M. Ream and A. Ruzicka, Cascadia
Type spec mass (g):51.7
Type spec location:Cascadia
Main mass:John A. Shea, 201 East Valley Rd, Wallingford, PA, 19086
Comments:Lab number CML0757; submitted by A. Ruzicka
   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)
References: Published in Meteoritical Bulletin, no. 104, MAPS 52, 2284, Octover 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12930/full
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
John A. Shea   

     This is 1 of 9772 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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