IIG Iron Meteorites


Description: This is a brand-new group of iron meteorites, formerly known as the Bellsbank grouplet. Structurally, the iron meteorites of the IIG group are all hexahedrites or coarsest octahedrites.


Formation history & Origin: In their structural and elemental compositions the IIG irons resemble the iron meteorites of group IIAB, but they contain even less nickel and unusual, abundant ribbons of the iron-phosphide schreibersite. These ribbons often cover 15% of the etched surface of a IIG iron. This strongly suggests that the formation of the IIG iron meteorites occurred in the outer regions of the core of a differentiated asteroid, probably distinct from the IIAB parent body.


Members: Thus far, this small group consists of just five members: Bellsbank, La Primitiva, Tombigbee River, Twannberg, and the recently discovered Guanaco, a meteorite that was found in the Atacama Desert, Chile, in 2000.

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