NWA 15818 ( 4,550 g )

Northwest Africa 15818 (NWA 15818)
(Northwest Africa)
Purchased: 2022
Classification: Carbonaceous chondrite (CO3)
History: The meteorite was purchased from a meteorite dealer in Mauritania.
Physical characteristics: Two large rocks weighing 5005 and 645 g, plus many small fargments, some partly covered with fusion crust.
Petrography: The meteorite shows a brownish interior and is predominantly composed of abundant small chondrules, CAIs, and mineral fragments set into a fine-grained matrix. Chondrules have a mean diameter of about 150 µm. Opaque phases are metal and troilite partly altered to iron oxides and hydroxides.
Geochemistry: Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, D. Au Yang, CEREGE) from analysis of one acid-washed 2.5 mg aliquot of a powdered 104 mg bulk sample is δ17O=-4.398‰, δ18O=-1.324‰ , Δ17O=-3.710‰ (slope 0.52, analytical uncertainties 0.08‰, 0.12‰, 0.03‰, respectively)
 
Place of purchase:
Mauritania
Date:
P 2022
Mass (g):
5650
Pieces:
many
Class:
CO3
Shock stage:
S1
Weathering grade:
moderate
Fayalite (mol%):
19.7±21.0 (0.6-65.1, n=18)
Ferrosilite (mol%):
2.7±1.6 (1.0-5.6, n=12)
Wollastonite (mol%):
1.2±0.3 (0.9-1.7, n=12)
Magnetic suscept.:
4.64
Classifier:
A. Greshake, MNB
Type spec mass (g):
29.2
Type spec location:
MNB
Main mass:
Boulaouane Taleb Ahmed
Comments:
Submitted by Ansgar Greshake