The Tleumbetskii intrusion is situated in the region of Chingiz-Tarbogotay. It is a large complex with an area of 175 km2. The earliest rocks are porphyritic medium-grained riebeckite-arfvedsonite-biotite granites and syenites which are cut by small stocks and dykes of peralkaline granosyenite and granite porphyry. Alteration of these rocks is expressed by the development of albite and chlorite and zones of greisen. The rocks are exceptionally rich in accessory minerals including fluorite, zircon, orthite, monazite, ferrothorite, topaz, ilmenite, titanite, apatite, pyrite, baryte, columbite and garnet with more rarely scheelite, rutile, anatase, galena and wulfenite.