Bencubbinites are rare & aesthetic meteorites. Texturally, they are chondrites & are naturally dominated by chondrules. However, they are very strange chondrites, because many of the chondrules in bencubbinites are metallic iron.
The sample shown below is a slice from the Gujba Meteorite, a bencubbinite that fell in northeastern Nigeria on 3 April 1984, but has only been subjected to scientific study since the early 2000s.
The Gujba Meteorite is dominated by metallic chondrules. Gujba's metal chondrules are slightly elongated spheroids containing iron and a little nickel. The large, light-colored rounded structures are silicate chondrules. Published research has shown that the silicate chondrules consist of forsterite olivine or pyroxene plus feldspathic glass. The matrix surrounding the large metal & silicate chondrules is principally composed of small silicate chondrule fragments.
Very few meteorites can be classified as bencubbinites, or CB chondrites. The details of their origin are not yet clear, and several hypothesized formation mechanisms have been proposed.
Chondrules of the Gujba Meteorite have been dated to 4.5627 billion years.
Bencubbinite slice, 4.6 x 3.8 cm in size.
The above information is mostly synthesized from:
Rubin et al. (2001) - Gujba: a new Bencubbin-like meteorite fall from Nigeria. 32nd Lunar and Planetary Science Conference, March 12-16, 2001, Houston, Texas. Abstract 1779.
Weisberg et al. (2002) - Gujba and origin of Bencubbin-like (CB) chondrites. 33rd Lunar and Planetary Science Conference, March 11-15, 2002. Abstract 1551.
Krot et al. (2005) - Young chondrules in CB chondrites from a giant impact in the early solar system. Nature 436: 989-992.
Weisberg et al. (2006) - Discovery of coesite and significance of high pressure phases in the Gujba CB chondrite. 37th Lunar and Planetary Science Conference, March 13-17, 2006. Abstract 1788.
Specimen acquired through the generosity of Lee & Mary Ellen St. John.