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Northwest Africa 618
Basic information Name: Northwest Africa 618
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 618
Observed fall: No
Year found: 2000
Country: (Northwest Africa)
Mass:help 126.1 g
Meteoritical Bulletin:  MB 103  (2014)  H3-5
Recommended:  H3-5    [explanation]

This is 1 of 81 approved meteorites classified as H3-5.   [show all]
Search for other: H chondrites, H chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 11 Dec 2014
Writeup from MB 103:

Northwest Africa 618 (NWA 618)

Northwest Africa

Purchased: 2000

Classification: Ordinary chondrite (H3-5)

History: One flattened 126.1 g stone containing weathered fusion crust and desert patina was found and sold to Michael Cottingham in Morocco. Thomas Webb acquired the sample in November 2000.

Physical characteristics: Dark orangish brown desert patina covers relict fusion crust, which covers ~45% of the oriented, flattened stone. Rollover lipping and minimal bubbling are displayed on the trailing edge of the specimen.

Petrography: Description and classification (A. Love, App): Sample is mottled orange, crosscut by a series of subparallel arcuate fractures and fine metallic shock veins, which separate roughly parallel regions of well-defined chondrules (average diameter 433 μm) and regions which display recrystallized chondritic texture composed of indistinct chondrules in recrystallized matrix with minimally weathered, irregular-shaped grains of FeNi and FeS. The sample does not appear to be brecciated, however arcuate fractures may obscure boundaries between clasts. Regions with unequilibrated material contain some zoned olivine, twinned grains of clinoenstatite and porphyritic chondrules with turbid mesostasis. CL observations show parallel regions containing less equilibrated material and equilibrated material segregated by arcuate metallic shock veins.

Geochemistry: (A.Love, App) Unequilibrated regions: Olivine Fa13.6±7.4 (Fa2.31-25.84 N=24); Low Ca pyroxene Fs12.9±4.9 (Fs3.39-18.4 N=19), Equilibrated regions: Olivine Fa21.1±0.3, N=12; Low Ca pyroxene Fs18.1±0.7, N=7.

Classification: Based on chemistry and CL signatures this is an ordinary chondrite (H3-5, S3, W2).

Specimens: 21.05g and 2 polished thin sections are on deposit at App

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2000
Mass (g):126.1
Shock stage:S3
Weathering grade:W2
Fayalite (mol%):13.6±7.4; 21.1±0.3
Ferrosilite (mol%):12.9±4.9; 18.1±0.7
Wollastonite (mol%):1.1±0.7; 2.41±0.2
Classifier:A. Love, App
Type spec mass (g):21.05
Type spec location:App
Main mass:TWebb
Comments:Submitted by Anthony Love
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
TWebb: No contact information provided., United States (private address)
References: Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
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     This is 1 of 8402 approved meteorites from (Northwest Africa) (plus 1899 unapproved names)

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