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Northwest Africa 13444
Basic information Name: Northwest Africa 13444
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13444
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 909 g
Classification
  history:
Recommended:  CK4/5    [explanation]

This is 1 of 15 approved meteorites classified as CK4/5.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated), CK chondrites, CK chondrites (type 4-6), and CV-CK clan chondrites
Comments: Approved 11 Nov 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13444 (NWA 13444)

(Northwest Africa)

Purchased: 2017 oct 29

Classification: Carbonaceous chondrite (CK4/5)

History: Purchased at Munich mineral show 2017 by Marc Jost from Aziz Habibi

Physical characteristics: Dark brownish black, wind-eroded, pitted surface, no fusion crust. Some protruding CAIs.

Petrography: Chondrules have a mean apparent diameter of 0.96 mm (N=48), maximum diameter 1.8 mm. Matrix (~70%) is significantly recrystallized with feldspar grain size of 10-40 μm. Magnetite is by far the most abundant opaque mineral, occurring as fine dust in the silicates, as single grains up to 50 μm and composite grains up to 300 μm. Sulfides only occur as inclusions in magnetite, but common iron hydroxides indicate the former presence iron sulfides. The meteorite is weakly shocked (S2). Almost complete weathering of sulfides (excluding inclusions in magnetite), olivines partly stained with Fe-hydroxides and partial transformation of magnetite to maghemite indicate strong weathering. Some veins of secondary calcite. The meteorite is brecciated based on some clearly visible clasts up to 3 mm.

Geochemistry: Olivine Fa32.1±1.5 (range Fa30.0-35.5, N = 18); low-Ca pyroxene Fs12.9±6.8Wo1.5±1.1 (N = 12); high-Ca pyroxene Fs17.1±0.9 (N = 4); feldspar An34.9±13.0Or1.7±1.2 (N =5). Silicates in the matrix are well equilibrated, large chondrules show Fe-poor, unequilibrated central parts. Magnetite is Cr-rich with Cr2O3 3.9±0.3 wt% (N = 11).

Classification: Based on abundance and recrystallization of matrix and mineral composition including Cr-content of magnetite this is a CK chondrite. Based on feldspar grain size and partially incomplete equilibration the petrographic grade is estimated as 4/5. Shock grade S2, strong weathering.

Specimens: 20.675 g and one polished thin section at NMBE, main mass: Marc Jost.

Data from:
  MB110
  Table 0
  Line 0:
Place of purchase:Munich
Date:P 2017 oct 29
Mass (g):909
Pieces:1
Class:CK4/5
Shock stage:S2
Weathering grade:strong
Fayalite (mol%):32.1±1.5 (N=18)
Ferrosilite (mol%):12.9±6.8 (N=12)
Wollastonite (mol%):1.5±1.1 (N=12)
Magnetic suscept.:4.68
Classifier:B. Hofmann, A. Rosén
Type spec mass (g):20.675
Type spec location:NMBE
Main mass:Marc Jost, Switzerland
Comments:Number as received: SJS 1802; NMBE number: 43407; submitted by Beda Hofmann
Institutions
   and collections
NMBE: Natural History Museum Bern Bernastrasse 15 CH-3005 Bern Switzerland, Switzerland; Website (institutional address; updated 2 Mar 2012)
SJS: Space Jewels Switzerland, 2555 Brügg, Switzerland (private address; updated 3 Jan 2010)
Catalogs:
References: Published in Meteoritical Bulletin, no. 110, in preparation (2021)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8416 approved meteorites from (Northwest Africa) (plus 1899 unapproved names)

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