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Northwest Africa 12818
Basic information Name: Northwest Africa 12818
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12818
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 241 g
Classification
  history:
Recommended:  LL3-5    [explanation]

This is 1 of 7 approved meteorites classified as LL3-5.   [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 3 Sep 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12818 (NWA 12818)

(Northwest Africa)

Purchased: 2018

Classification: Ordinary chondrite (LL3-5)

History: Marc Jost purchased from a Moroccan dealer at the 2018 Ensisheim meteorite show.

Physical characteristics: The 241g sample has a brown weathered exterior with an irregular shape and a weathered fusion crust. The cut face shows the interior is a breccia composed of clasts of equilibrated lithologies set within a host of flattened chondrules that define a foliation.

Petrography: Description and Classification (A. Love, App) Sample is a breccia composed of sparse, angular-rounded clasts of recrystallized equilibrated chondrite set within a host of densely-packed, unequilibrated chondrules and fragments (avg. dia. 917 μm, N=58) with fine-grained rims and rare matrix lumps.

Geochemistry: (A. Love, App) Host: Olivine Fa18.6±11.1 (Fa0.5-37.6), Fe/Mn=53.5±17.0, mean Cr2O3 in ferroan olivine=0.1±0.1 (0.0-0.4), PMD=51% N=16; low Ca pyroxene Fs12.3±7.4Wo0.8±0.8 (Fs1.4-29.5Wo0.2-3.5), PMD=47%, N=14. Clast 1: Olivine Fa28.2±2.5 (Fa22.9-30.1), Fe/Mn=55.0, N=6; low Ca pyroxene Fs25.1±0.1Wo1.7±0.4, N=3. Clast 2: Olivine Fa30.4±0.2, Fe/Mn=56.5, N=6; low Ca Pyroxene Fs25.2±0.2Wo1.4±0.5, N=3.

Classification: Ordinary Chondrite (LL3, 5C-S3, W3) Based on chondrule size and magnetic susceptibility and mineral compositions, this sample is an LL ordinary chondrite. Based on textures and mineral compositions, this sample is an LL3-5 breccia. Host is ≥3.2 based on PMD of Ol and Opx, CL observations indicate ≥3.3 following Huss et al. (2006), and mean and standard deviation of Cr2O3 in ferroan Ol ≥3.2.

Specimens: Marc Jost (SJS) holds the main mass. 2 slices weighing 33.2 g and a polished mount and thin section and mount are on deposit at App.

Bibliography:
  • 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:
  MB108
  Table 0
  Line 0:
Place of purchase:Ensisheim
Date:P 2018
Mass (g):241
Pieces:1
Class:LL3-5
Shock stage:C-S3
Weathering grade:W3
Fayalite (mol%):18.6±11.1; 28.2±2.5; 30.4±0.2
Ferrosilite (mol%):12.3±7.4; 25.1±0.1; 25.2±0.2
Wollastonite (mol%):0.8±0.8; 1.7±0.4; 1.4±0.5
Magnetic suscept.:4.18
Classifier:A. Love, App
Type spec mass (g):33.2
Type spec location:App
Main mass:Marc Jost (SJS)
Finder:Unknown
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)
SJS: Space Jewels Switzerland, 2555 Brügg, Switzerland (private address; updated 3 Jan 2010)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7005 approved meteorites from (Northwest Africa) (plus 2002 unapproved names)

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