A granite intrusion of 9x3.5-4 km Akkoitas possibly is sill-like in form. Biotite granites are the most abundant rocks with less abundant areas of riebeckite and aegirine-riebeckite granites. Aegirine-riebeckite granites are mostly restricted to the upper part of the intrusion, where they form dome-shaped outcrops containing xenoliths of country rock. There is a very strongly developed system of dykes.
ZIRYANOV, V.N. 1969. Petrology of the metasomatically altered granitoids and alkaline rocks of the Chingizsky zone. Nauka, Moscow. 160 pp.