It is surrounded by intensely deformed granite gneiss. The basal unit of the complex is anorthosite, overlain by gabbro and monzonite. A charnockite alteration zone rims the complex. The contacts between the ore and host rock are generally sharp, however, at the flanks of the ore zone xenoliths of anorthosite are common. Banding is either weak or absent.
Magnetite occurs as euhedral crystals.
Apatite is also common with trace quantities of chromium spinel. Genesis Generally thought to be the product of immiscible liquid segregation, but still remains controversial among European geologists. Occur in a geographically continuous belt. Charnockite, an anhydrous felsic rock, is common surrounding the anorthosite complexes. Genesis not well understood, but thought to be related to buoyant blockage of magma at the crust-mantle boundary and subsequent partial melting and fractionation.