The 17 km2 sub-volcanic intrusion of Tokailuashu is emplaced in late Ordovician sediments and is located south of the Kolbashinskii volcanic field (No. 1). The rocks consist of augite, aegirine-augite and aegirine peralkaline syenites, melasyenite, syenite porphyry, monzonites and shonkinites. Dyke rocks include peralkaline syenite pegmatite and lamprophyres. The country rocks are granitoids and volcanics.