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Northwest Africa 16464
Basic information Name: Northwest Africa 16464
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 16464
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 5.02 kg
Classification
  history:
Recommended:  L3.15    [explanation]

This is 1 of 11 approved meteorites classified as L3.15.   [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 16 Feb 2024
Writeuphelp
Writeup from MB 113:

Northwest Africa 16464 (NWA 16464)

(Northwest Africa)

Purchased: 2022

Classification: Ordinary chondrite (L3.15)

History: Four partially fusion crusted stones were purchased in June 2022 by Pat Brown from Mostafa Hnini. One mass of 1891.0 g was cut; the other masses are: 1446.9, 1588.3, and 93.0 g.

Physical characteristics: The fusion crust (covering about 60% of the surface area of each stone) is black and relatively fresh. The fractured surfaces are a dark brown to black color and are well covered by desert varnish. Under reflected cross polarized light all stones show closely packed chondrules with very little matrix.

Petrography: (P. Brown, MeteoriticsLab; D. Sheikh, Cascadia) Sample is composed of well-defined chondrules (Av. ~601±320 µm, up to 1.8 mm, n=106) containing both primary and devitrified glass, and mm-sized clasts, set within a dark, mostly opaque matrix. Some of the clasts identified include fine-grained dark inclusions that are compositionally similar to mean CI/CM carbonaceous chondrite groups (Wasson and Kallemeyn, 1988). Accessory phases identified include Fe-Ni metal and troilite.

Geochemistry: (D. Sheikh, Cascadia) Olivine (Fa18.7±8.0, range Fa1.7-44.1, n=178), Cr2O3 in ferroan olivine (0.24±0.15 wt. %, range 0.08-0.74, n=176), Low-Ca Pyroxene (Fs9.6±8.2Wo1.2±1.4, range Fs1.4-25.3Wo0.2-5.4, n=47); Dark inclusion bulk (in mg/g) (Na=6.3±0.5, Mg=115.3±2.8, Al=9.6±0.9, Si=127.1±5.3, P=1.6±0.1, S=51.6±1.1, Ca=9.3±1.1, Ti=0.3±0.1, Cr=3.1±0.5, Mn=1.7±0.1, Fe=227.7±2.0, Ni=9.2±0.1, n=2).

Classification: Ordinary Chondrite (L3.15). L group suggested from magnetic susceptibility and average chondrule diameter; subtype 3.15 estimated due to mean Cr2O3 value and standard deviation from ferroan olivines according to Grossman and Brearley (2005), similar to Bishunpur.

Specimens: 24.6 g type specimen at Cascadia, main mass with Pat Brown.

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:
  MB113
  Table 0
  Line 0:
Place of purchase:Online
Date:P 2022
Mass (g):5019.2
Pieces:4
Class:L3.15
Shock stage:S3
Weathering grade:W1
Fayalite (mol%):18.7±8.0
Ferrosilite (mol%):9.6±8.2
Wollastonite (mol%):1.2±1.4
Magnetic suscept.:4.58
Classifier:D. Sheikh, Cascadia; P. Brown, MeteoriticsLab
Type spec mass (g):24.6
Type spec location:Cascadia
Main mass:Pat Brown
Comments:CML 1645; PB-07; submitted by Daniel Sheikh
Institutions
   and collections
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 113, in preparation (2024)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 9829 approved meteorites from (Northwest Africa) (plus 1851 unapproved names)

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