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Northwest Africa 6454
Basic information Name: Northwest Africa 6454
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6454
Observed fall: No
Year found: 2005
Country: (Northwest Africa)
Mass:help 300 g
Classification
  history:
Meteoritical Bulletin:  MB 99  (2011)  L-melt rock
Recommended:  L-melt rock    [explanation]

This is 1 of 35 approved meteorites classified as L-melt rock.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Melted chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 28 Dec 2010
Writeuphelp
Writeup from MB 99:

Northwest Africa 6454 (NWA 6454)

(Northwest Africa)

Purchased: February, 2005

Classification: Ordinary chondrite (L, melt rock)

History: In February 2005, Mr. Blaine Reed sold a portion of the sample to Mr. Turecki and that same year pieces were acquired by Cascadia from both Mr. Reed and Mr. Turecki.

Physical characteristics: The single stone is largely covered by a shiny black fusion crust that appears to be relatively unweathered.

Petrography: (A. Ruzicka and Melinda Hutson, Cascadia): The meteorite lacks chondritic texture and is dominated by fine-grained (<20 μm) euhedral to subhedral olivine set in glass. Metal and sulfide (~5-10% of sample) form cellular and dendritic intergrowths in composite particles up to a few millimeters across. Silicate portions can be subdivided into coarser, clast-like portions (olivine grain size 5-15 μm across) and finer-grained interstitial areas (olivine grains <3 μm across). Shock veins connect some of the metal-sulfide particles and in places merge into the finer-grained silicate regions. Clasts of olivine and low-Ca pyroxene are present which show a recrystallization texture (granular subgrains meeting in triple junctions).

Geochemistry: (K. Hauver and A. Ruzicka, Cascadia) Metal consists of kamacite with Ni = 6.12 ± 1.54 wt% and Co = 0.84 ± 0.06 wt% (N=7); martensite with Ni = 12.8 ± 2.9 wt% and Co = 0.77 ± 0.10 wt% (N=51), taenite with Ni = 27.7 ± 6.8 wt% and Co = 0.61 ± 0.11 wt% (N=12), and tetrataenite. Sulfide dominated by troilite with a minor Cr-sulfide phase.

Classification: Ordinary chondrite melt rock (shock melt). Textures of silicate and metal-sulfide particles suggest rapid cooling from a melt and the presence of shock-recrystallized xenocrysts. Kamacite Co contents fall within the range of L chondrites and the overall metal + sulfide content is consistent with this type of protolith.

Specimens: Type specimens available at Cascadia include 4 pieces totaling 20.0 g, plus one polished thin section and one polished potted butt. Turecki holds the main mass.

Data from:
  MB99
  Table 0
  Line 0:
Place of purchase:Tucson Gem and Mineral Show
Date:P February, 2005
Mass (g):300
Pieces:1
Class:L-melt rock
Weathering grade:W1
Classifier:Alex Ruzicka, Kristy Hauver, Melinda Hutson (Cascadia)
Type spec mass (g):20.0
Type spec location:Cascadia
Main mass:Turecki
Comments:Submitted by Alex 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)
Reed: Blaine Reed, P.O. Box 1141, Delta, CO 81416, United States; Website (private address)
Turecki: Stan Turecki, 5618 Regis Ave., Port Richey, Florida, United States (private address; updated 28 Dec 2010)
Catalogs:
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6900 approved meteorites from (Northwest Africa) (plus 2027 unapproved names)

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