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Northwest Africa 13738
Basic information Name: Northwest Africa 13738
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13738
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 431 g
Classification
  history:
Recommended:  LL3    [explanation]

This is 1 of 369 approved meteorites classified as LL3.   [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 13 Feb 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13738 (NWA 13738)

Adrar, Algeria

Purchased: 2020

Classification: Ordinary chondrite (LL3)

History: John Higgins purchased 9 pieces totaling 430.8 g, sourced from a market in Adrar in June 2020.

Physical characteristics: Sample has a tabular shape, an orangish-brown weathered exterior showing abundant close-packed chondrules. A cut face shows the interior contains abundant chondrules set in a brown fine-grained matrix.

Petrography: Description and classification (A. Love, App) Sample shows chondritic texture composed of numerous, well-defined, close-packed, unequilibrated chondrules with an avg. apparent diameter 640µm (n=106) set within a fine-grained opaque matrix. The sample contains a rounded clast with dispersed chondrules (~5 vol%, avg. diam. of 317 µm, n=15). Additional minerals are: chromite, troilite, diopside, and Na and Ca-glasses.

Geochemistry: Host: Olivine (Fa16.8±10.8 (range Fa0.6-37.7), Cr2O3=0.12±0.06, Fe/Mn=32.7±16.5, n=21); low Ca pyroxene (Fs17.7±11.0Wo1.7±1.1, Fe/Mn=26.6±18.1, n=15); high Ca pyroxene (Fs27.2Wo30.1, Fe/Mn=14.3, n=1). Clast: Olivine (Fa7.6-8.7, Fe/Mn=106.2-34.0, n=2); low Ca Pyroxene (Fs5.0-5.3Wo0.6-0.3, Fe/Mn 10.3-16.4, n=2).

Classification: Ordinary Chondrite (LL3, C-S2, W3). Based on chondrule size and magnetic susceptibility, sample is an LL chondrite. Poorly equilibrated mineral compositions, mean and standard deviation of Cr2O3 in Type II chondrules (~3.2) (Grossman and Brearley, 2005), presence of yellow mesostasis in chondrules (3.1/3.2), abundant chondrule glass (<3.3) suggest sample is LL3.2/3.3.

Specimens: John Higgins holds the main mass. Three slices weighing a total of 23.09 g and a 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)
Data from:
  MB110
  Table 0
  Line 0:
State/Prov/County:Adrar
Date:P 2020
Mass (g):430.8
Pieces:9
Class:LL3
Shock stage:C-S2
Weathering grade:W3
Fayalite (mol%):16.8±10.8
Ferrosilite (mol%):17.7±11.0; 27.2
Wollastonite (mol%):1.7±1.1; 30.1
Magnetic suscept.:3.65
Classifier:A. Love, App
Type spec mass (g):23.09
Type spec location:App
Main mass:John Higgins
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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 110, in preparation (2021)
Find references in NASA ADS:
Find references in Google Scholar:
Geography:

Algeria
Coordinates:Unknown.

Statistics:
     This is 1 of 163 approved meteorites from Adrar, Algeria (plus 1 unapproved name)
     This is 1 of 1113 approved meteorites from Algeria (plus 27 unapproved names) (plus 4 impact craters)

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