Platinum-group elements in the chromitites of the Bushveld Complex: New evidence on how the PGE got there

摘要

The Bushveld Complex contains 75% of the world's resources of Pt, and of this, 58% occur in one unit, the UG-2 chromitite. Most of the other 20 chromitite horizons of the Bushveld are enriched in PGE to varying degrees. However, in contrast to other major PGE hosts, the Merensky Reef and Platreef, in which the PGE are closely associated with Fe-Ni-Cu sulfides, most of the chromitites contain very little sulfide. This paper reports preliminary results of a study of the PGE contents of the 21 chromitite horizons in the Bushveld complex, in 6 specific locations that have been chosen to represent the main "troughs" of the Eastern and Western lobes of the complex. It should be stressed that not all chromitite horizons are developed in every trough.