Abstract: The Kızılcaören district is situated about 150 km. west of capital Ankara, is an unique LREE andthorium deposit of Turkey. The deposit is located on the eastern margin of the Karakaya formation between the Pontidebelt in the north and the Anatolide-Tauride platform in the south.The basement consists of serpentinites in late Paleozoic to early Triassic age, overlain by highly deformed andlocally variable anchimetamorphic sediments which are related to Triassic. Dominant Ethologies of Triassic formationinclude phyllite, sandstone, shale, slate and mudstones. This formation also contains limestone olistolithes of Permianage, diabasic dykes and lava flows with pillows. Standstone and massive fossiliferous limestone of Jurassic age overliethe Triassic formation. Late Oligocene intrusive activities produce carbonatites. Early Miocene extrusive activitiesproduce trachytic pyroclastic pyroclastics, trachytes and phonolites. Two different phase of carbonatite have been distinguished. The oldest ones occur as dykes up to 1.5 m. in widthand cut through the Triassic host rocks and ophiolities. Younger generation of carbonatites occur in the form of dykesranging in size 1-10 cm. and cut through the breccia pipes and veins.The deposit consists of bastnaesite-fluorite-barite mineralizations in economic grade. The mineralization ismainly hosted by anchimetamorphic sediments and rarely trachytic tuffs and breccia pipes. There are five breccia pipes inthe area which are formed by magmatic process. The mineralization consists of the infilling of radial circular and funnelshaped fractures and breccia pipes.Fracturing, brecciation and mineralization are associated with the late Oligocene carbonatite intrusions.Prebreccia mineralization is dominated by fluorite and barite. Post-breccia mineralization is dominated by REEmineral phases. Thorbastnaesite is the most abundant and widespread mineral phase.Minör phases are fluocerite andbrockite. Fluid inclusion studies suggest that early stage of prebreccia mineralization was between 550-300° and latestage 300-190 C°. The early stage of postbreccia mineralization was between 300-500 C°, whereas the final stage wasbelow 250 C°.The bastnaesite-fluorite-barite deposit of Kızılcaören is formed by the upwelling of the high temperaturecarbonatitic magmatic fluids (carbo-thermal fluids) guided by circular, radial and funnel shaped fractures, at lateOligocene-early Miocene time.