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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 365 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, 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 162 approved meteorites from Adrar, Algeria (plus 1 unapproved name)
     This is 1 of 1088 approved meteorites from Algeria (plus 26 unapproved names) (plus 4 impact craters)

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