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Northwest Africa 16347
Basic information Name: Northwest Africa 16347
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 16347
Observed fall: No
Year found: 2021
Country: (Northwest Africa)
Mass:help 288 g
Classification
  history:
Meteoritical Bulletin:  MB 112  (2024)  L3.10
Recommended:  L3.10    [explanation]

This is 1 of 10 approved meteorites classified as L3.10.   [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 3 Jan 2024
Writeuphelp
Writeup from MB 112:

Northwest Africa 16347 (NWA 16347)

(Northwest Africa)

Purchased: June 2021

Classification: Ordinary chondrite (L3.10)

History: Mr. Jasper Spencer purchased two pieces (219 and 69 g) of a chondrule-rich meteorite from a Mauritanian dealer in June 2021 via Facebook Messenger. Mr. Spencer donated pieces from each stone to Cascadia for classification

Physical characteristics: Physical Characteristics: Samples received by Cascadia showed numerous well-defined chondrules on a brownish polished cut face. Samples are cross-cut by weathering veins. Exterior is covered by desert varnish and caliche.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): Most (~90-95%) of the metal and troilite in the section has been replaced (borderline W3/W4), making a determination of metal abundance difficult. Weathering product is approximately 7-10 area% both in thin section and on cut faces of hand specimens. The thin section is small and contains two large clasts, along with occasional chondrules and a large number of chondrule fragments set in a fragmental matrix. Mean chondrule apparent diameter (2D measurements) in the section is 521±224 µm (range=277-1093 µm), N=13. A comparison of the thin section with the cut face of the largest hand specimen indicates that this measurement is typical of the sample. Chondrule mesostases are predominantly glassy, containing few or no crystallites. The larger of the two clasts is rectangular (3 × 2.3 mm exposed area) and is partially surrounded by a very fine-grained rim enriched in Fe, Ni, Al, and Ca compared to both the clast and nearby host meteorite. The clast is comprised of thin bars of olivine separated by aluminous low-Ca pyroxene grains. Small patches of intergrown aluminous high-Ca pyroxene and anorthitic glass occur interstitial to olivine and low-Ca pyroxene. The smaller of the two clasts (1.9 mm × 1.4 mm exposed area) consists mainly of large (up to ~0.6 mm long) orthopyroxene grains with oscillatory and asymmetric Fe-Mg zoning, poikilitically enclosing notably smaller (up to 30 µm across) olivine grains. No mineral-chemical data was obtained for this clast.

Geochemistry: Host meteorite olivine (Fa18.1±10.2, range Fa0.2-36.0, N=57; Cr2O3=0.34±0.21 wt% (low FeO grains excluded), N=51); low-Ca pyroxene (Fs13.5±9.0Wo0.9±0.8, range Fs1.0-26.2Wo0.3-2.7, N=39). Largest clast olivine Fa5.9±0.3, N=9; low-Ca pyroxene Fs2.5±0.4Wo4.5±0.2, Al2O3=1.0±0.1 wt%, N=5; high-Ca pyroxene Fs4.1±0.4Wo34.5±6.0, Al2O3=2.5±0.9 wt%, N=6. Glass co-existing with high-Ca pyroxene is close to stoichiometric feldspar (5.02 cations per 8 oxygen) and is anorthitic (~An94, N=4) with excess Fe, Ni, Ti, and Mg.

Classification: Ordinary chondrite (L3.10). The mean chondrule diameter is most consistent with L-group meteorites; Cr2O3 abundance and standard deviation in olivine indicates type 3.10.

Specimens: Cascadia holds 48.3 g in three pieces, as well as a polished thin section and material in an epoxy butt; Mr. Jasper Spencer holds the main mass.

Data from:
  MB112
  Table 0
  Line 0:
Place of purchase:FB Messenger
Date:P June 2021
Mass (g):288
Pieces:2
Class:L3.10
Shock stage:S2
Weathering grade:W3
Fayalite (mol%):18.1±10.2 (N=57)
Ferrosilite (mol%):13.5±9.0 (N=39)
Wollastonite (mol%):0.9±0.8 (N=39)
Classifier:M. Hutson and A. Ruzicka, Cascadia
Type spec mass (g):49.4
Type spec location:Cascadia
Main mass:Mr. Jasper Spencer
Comments:Lab number CML 1436; submitted by Melinda Hutson
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)
Catalogs:
References: Published in Gattacceca J., McCubbin F. M., Grossman J. N., Schrader D. L., Cartier C., Consolmagno G., Goodrich C., Greshake A., Gross J., Joy K. H., Miao B. and Zhang B. (2024) The Meteoritical Bulletin, no. 112. Meteoritics & Planetary Science 59, 1820–1823. ?
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Melinda Hutson      
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 9829 approved meteorites from (Northwest Africa) (plus 1851 unapproved names)

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