Description
0.068g part slice sold in a collection box with label/certificate.
Northwest Africa 11345 (NWA 11345)
(Northwest Africa)
Purchased: 2016 Nov
Classification: Carbonaceous chondrite (CM2)
Physical characteristics: Irregular dark stone. Cut surface reveals a dark interior with lighter chondrules to mm size.
Petrography: Chondrules (some with dust rims) and chondrule fragments (33 vol%) set in a fine-grained matrix (67 vol%). Modal abundances from point counting (N=296). Chondrule average apparent diameter 230±110 μm (N=32). XRD over a several mm2 area on a polished section (D. Borschnek, B. Devouard, CEREGE) reveals the presence of phyllosilicates as typically observed in type 2 chondrites using the same experimental setup.
Geochemistry: Olivine Fa46.1±10.4, range Fa33.0-58.0 (N=6). Orthopyroxene Fs3.0±0.9Wo1.9±0.8, range Fs2.1-4.5 (N=5). Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 320 mg bulk sample is δ17O=2.13‰, δ18O=8.95‰, Δ17O=-2.55‰ (linearized, slope 0.5247, analytical uncertainties 0.08, 0.12, 0.03 all ‰ respectively). Magnetic susceptibility log χ (× 10-9 m3/kg)=4.46.
Classification: CM2
Specimens: Type specimen at CEREGE. Main maiss with Kuntz.
