Geology, origin and economic importance of the copper mineralization of Keban (Elazığ) east euphrates Keban Dere area

ABSTRACT Ph.D Thesis GEOLOGY, ORIGIN AND ECONOMIC IMPORTANCE OF THE COPPER MINERALIZATION OF KEBAN (ELAZI?) EAST EUPHRATES KEBAN DERE AREA Leyla KALENDER Fırat University Gradute School of Secience and Technology Department of Geologycal Engineering 2000, Page: 110 The studied area is located in and around Keban township which is 40 kms west of Elazığ. The study deals with the geology, mineralogy, geochemistry, fluid inclusion studies, ore microscopy, structural geology and petrological features of lithological units in order to investigate origin of the copper mineralization. Two geological units are present in the study area. These are; Keban Metamorphites (Permo-Carboniferous) and Keban magmatic rocks (Upper Createous). According to fracture analysis, copper mineralizations are placed in KB-GD striking syngenetic tension fractures and pyrit, fluorit and molybdenite mineralizations in shear fractures. Occurance of sulfides change upward from dissemination and finally vein occurance indicating effect of structural control. Microthermometric measurements made on primary and secondary fluid inclusions in quartz in the mineralized quartz veins and inclusions in quartz, calcite and fluorite related to copper mineralizations. The temparature for the quartz ^formationVI change in temperature interval of 360-380°C and have salinity values of avarage 22 wt %NaCl eq. The fluid inclusions which are in quartz of mineralized veins and cointain doughter minerals, have an average homogenization temperature of 374 °C and avarage salinity of 17 wt %NaCl eq. In primary fluid inclusions of calcites, the formation temperature interval is 124 -193°C and have salinity values of 23-28 wt %NaCl eq. In flourites fluid inclusions the formation temperature are avarege 109°C and have salinity values 18,9 wt %NaCl eq. In secondary fluid inclusions salinity values are low because, hydrothermal fluids have effected by meteoric water. In primary fluid inclusions salinity values are high, implying circulations of hydrothermal fluids in the marine sediments. All of the fluid inclusion studies and investigations on mineralization, suggest that quartz is mineralized in catathermal system and the other minerals calcite, fluorit in epithermal system. Magmatic rocks of the studied area are called Keban magmatic rocks by previous workers. This unit consists of syenite, quartz syenite, monzonites, quartz monzonites. Copper deposits have high concentration in quartz monzonites and quartz syenite. The correlation analysis shows that TİO2 correlate with Th, Y, Nb, Ga, Sr, Ba ; Fe203 with Co ; K20 with Y, Ba, Zn ; Zr with Cu. The mineral assemblage is made of pyrite, chalcopyrite, baryite, calcite, galena, sphalerite, and represents a hydrothermal type mineralization. Investigation results, indicate a low- sodic- calcitic- potassic alteration type. In Y-Nb and Y+Nb-Rb diagrams, Keban Magmatic rocks were plotted in the volcanic arc area. Rl and R2 diagram shows Keban magmatic rocks formed in the late orogenic stage. In conclusion, the origin of the Keban Dere copper mineralization is considered as porphyry type deposit in magmatics and vein type mineralizations connected with porphyry system. Key words: Fluid inclusion, porphyry copper, copper and Keban. v >- ?