Khushagol

This massif covers an area of about 7 km2 and cuts Proterozoic schists, granites and limestones, the last of which contain graphite. The intrusion consists of syenites, in which gabbro xenoliths occur, peralkaline syenites, which are the dominant rocks of the complex and include riebeckite and riebeckite plus pyroxene types, granosyenites and nepheline syenites. Gabbros, gabbro-diorites and syenite-diorites were the first rocks to be emplaced and occur as minor bodies of 0.2x0.2 km up to 0.4-2.8 km across. They are fine- and medium-grained rocks of plagioclase (45-50%), hedenbergite (15-20%), biotite (10-20%), amphibole (10-15%) and olivine (0.6%) with accessory apatite, carbonate, ilmenite, magnetite and zircon. These were followed by hedenbergite syenites then by the intrusion of nepheline syenites, which are essentially foyaites. Igneous activity was completed by the injection of aegirine-hedenbergite-riebeckite syenites. Peralkaline granites are also present, but their place in the igneous sequence is not clear, although they are likely to be a younger part of the complex. Details on rock and mineral chemistry and temperatures of crystallization will be found in Romanov (1974 and 1976).