Fluid inclusion studies and geochemistry of rare earth elements of hydrothermal fluorites from Pohrenk, Kirsehir, Central Turkey

Fluorite mineralization occurs along fractures and cracks of Middle Eocene and Pliocene limestones and marls in the north and northeast of the Pohrenk region (CiFekdagi, Kirsehir). Tb/Ca - Tb/La and Y/Ho ratios were obtained from REE contents of fluorites which have revealed that mineralization is o f hydrothermal type. Negative Ce anomalies and positive Eu anomalies reflec t that hydrothermal solutions once had high oxygen fugacity. Fluid inclusio n studies indicate that homogenization temperatures of mineralization varie d between 90 degreesC and 200 degreesC, and hydrothermal solutions are comp osed of NaCl + KCl + MgCl2 + H2O. In addition, salinity measurements show t hat hydrothermal solutions were mixed with meteoric or rock formation water . Geologic setting, REE geochemistry and fluid inclusion studies suggest th at mineralization was deposited from a solution generated by mixing of magm atic and meteoric water under epithermal conditions.