||CBb (Bencubbin-like meteorite)
||Found 2003, Russia
||1 dpu thin section, 1 spc thin section
Carbonaceous chondrite (Bencubbin-like meteorite)
One stone, weighing 16 kg, was found by a tractor driver in a field during harvest carrying in
the Ishimbai region of Bashkortostan, close to the Isheyevo village. A small piece of the
meteorite was issued to the Vernadsky Institute by Kazakov D.A., and Polozkov A.G,
September 2004. Mineralogy and classification (Ivanova M.A. Vernad., Ulianov A.A. MSUM).
Fusion crust is well developed, dark brown. The meteorite consists of FeNi metal grains, C,
POP, rare BO chondrules (0.02-1 mm in size), chondrule fragments, CAIs, and matrix lumps.
FeNi metal comprises from 50 to 70 vol%, and contains 4.2-8.4 wt% Ni, 0.2-0.5 wt% Co, and
0.03-0.6 wt% Cr; Co/Ni ratio is approximately solar. C chondrules don’t contain any FeNi
metal grains, they are Mg-rich, and consist of pyroxene-rich cryptocrystalline material. Olivine,
Fa2.5, rare FeO-rich olivines, Fa10-38 ; pyroxene, Fs2.1Wo1.7 , FeO-rich pyroxene, Fs8-
12Wo0.8-1.8; troilite is Cr-rich, 2.5 wt% Cr. INAA data for a 20 mg chip: 2.74 wt.% Ni; 717
ppm Co; 2608 ppm Cr, 8.2 ppm Sc, and 1.59 ppm Ir. Petrological type 3; shock stage, S1;
weathering grade, W1. Specimens: a type specimen, 24.3 g, and two sections, Vernad; main
mass with anonymous finder.