The 7.5 km2 Iisorskii intrusion lies on the northwestern margin of a much larger granitoid massif of the same age. The relationship of the Iisorskii peralkaline granite, which contains riebeckite and annite, to the more extensive granitoids is not clear, but many investigators consider the peralkaline granites to be an alkaline facies generated by alkali metasomatism and zirconium-niobium mineralization.
ERMOLOV, P.V., VLADIMIROV, A.G. and TIKHOMIROVA, N.I. 1988. The petrology of silica oversaturated agpaitic alkaline rocks. Nauka, Novosibirsk. 86 pp.
ZIRYANOV, V.N. 1964. Nepheline syenites of the middle Prichingiz. Izvestia Akademii Nauk Kazakhstan SSR, Alma-Ata. Seriya Geologicheskaya, 5: 57-67.