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Northwest Africa 8457
Basic information Name: Northwest Africa 8457
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8457
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 54.6 g
Classification
  history:
Meteoritical Bulletin:  MB 103  (2014)  LL3.2
Recommended:  LL3.2    [explanation]

This is 1 of 20 approved meteorites classified as LL3.2.   [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 4 Jul 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 8457 (NWA 8457)

(Northwest Africa)

Purchased: 2014

Classification: Ordinary chondrite (LL3.2)

History: A partially crusted stone weighing 54.6 g was found in Morocco and purchased by Blaine Reed at the Tucson Gem and Mineral Show in February of 2014

Physical characteristics: Sample is irregularly shaped and contains minor amounts of weathered fusion crust.

Petrography: Description and classification (A. Love, App): Sample is dark-colored and displays numerous close-packed large (up to 2.5 mm) unequilibrated chondrules (avg. dia. 702 μm). Chondrules commonly contain mesostasis that displays yellow CL (44%) and blue CL (53%). Many chondrules display fine-grained rims composed of clastic and amorphous silicate and metal materials. Sample contains many Fe-Oxides and a single irregular-shaped metal grain composed of rounded taenite nodules with surrounded by rims of kamacite and troilite.

Geochemistry: (A.Love, App) Fa12.0±7.4 (Fa0.0-29.3 n=23), Fe/Mn=53.68, Cr2O3 in ferroan olivine is 0.28±0.09 wt%; Low Ca pyroxene Fs8.4±7.6Wo1.6±1.5, N=8.

Classification: Ordinary Chondrite (LL3.2 S3 W3). LL based on chondrule diameter and Fe/Mn ratios in olivine. Estimation of subtype based on mean content and variability of wt% Cr2O3 in ferroan olivine after Grossman and Brearley (2005) and CL signature of chondrule olivines and mesostasis of Huss et al. (2006).

Specimens: A 10.95 g type specimen and one polished thin section are on deposit at App.

Bibliography:
  • Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)
  • Huss, G.R., Rubin, A.E. and Grossman, J.N. (2006) Thermal Metamorphism in Chondrites. in Meteorites and the Early Solar System II, D.S. Lauretta and H.Y. McSween Jr. (eds.), University of Arizona Press, Tucson, 943 pp., 567-586. (link)
Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Tuscon Gem and Mineral Show
Date:P 2014
Mass (g):54.6
Pieces:1
Class:LL3.2
Shock stage:S3
Weathering grade:W3
Fayalite (mol%):12.0±7.4, N=23
Ferrosilite (mol%):8.4±7.6, N=8
Wollastonite (mol%):1.6±1.5
Classifier:A. Love, App
Type spec mass (g):10.95
Type spec location:App
Main mass:Blaine Reed
Finder:Anonymous
Comments:Submitted by Anthony Love
Institutions
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
Reed: Blaine Reed, P.O. Box 1141, Delta, CO 81416, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6781 approved meteorites from (Northwest Africa) (plus 2061 unapproved names)

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