Sample No.: PCA82518

Location: Pecora Escarpment

Field No.: 2782

Weight (gms): 21.9 Meteorite Type: E4 Chondrite

Physical Description: Roberta Score

The fusion crust covering PCA8 is shiny, iridescent, and ranges in color from orangish-red to brown to black. The exterior is dotted with numerous vugs that are lined with fusion crust. Dark brown matrix with abundant chondrules (as large as 3 mm in diameter) and metal make up the interior surfaces. Dimensions: 3 x 2.5 x 2 cm

Petrographic Description: Brian Mason

Chondrules are abundant, but are small, ranging from 0.3 to 0.9 mm in diameter; they consist of granular or fine-grained pyroxene. The matrix consists largely of granular pyroxene, with lesser amounts of nickel-iron and sulfides, and a little plagioclase. The meteorite is considerably weathered, with brown limonitic staining throughout the section. Microprobe analyses show that the pyroxene is almost pure MgSiO3 (FeO 0.2-0.8%, mean 0.5%; A12O3 0.07-0.7%, mean 0.5%; CaO 0.04-0.7%, mean 0.2%; TiO2, MnO, less than 0.1%). Plagioclase is almost pure albite (K2O 0.6%, CaO less than 0.1%). One grain of forsteritic olivine was analyzed. The meteorite is an enstatite chondrite, and since part of the pyroxene is polysynthetically twinned clinoenstatite, it is classified as E4.