Geochemical, stable isotopic (S, O, H, C), microthermometric and geochronological (U-Pb) evidence on the genesis of the Pınarbaşı porphyry Cu-Mo mineralization (Gediz-Kütahya, Western Turkey) (original) (raw)

2019, Journal of Geochemical Exploration

The Pınarbaşı porphyry Cu-Mo mineralization is located at northwest of Gediz (Kütahya-Turkey) and east of Simav (Kütahya-Turkey) in western Anatolia. The Pınarbaşı Cu-Mo mineralization is hosted by Pınarbaşı granitoidic intrusion consisting of granite, granodiorite and quartz monzonite. Geochemical and geochronological evidences for Pınarbaşı granitoidic rocks show that they are high-K calc-alkaline, and I-type granitoid magma likely developed post-collisional extensional regime. The U-Pb zircon age of granite (18.88±0.17 Ma) and quartz monzonite porphyry (18.27±0.14) obtained from the Pınarbaşı granitoid show Early Miocene (Burdigalian). The Pınarbaşı Cu-Mo mineralization predominantly comprises molybdenite, chalcopyrite, galena, sphalerite, pyrite, fahlore, magnetite, bornite, hematite, jarosite, malachite and orpiment occurred in disseminated form in veins/veinlets associated with potassic, phyllic (sericitic) and advanced argillic alteration zones. According to the paragenetic and crosscutting relationships of veins/veinlets, the ore-forming process were divided into three stages; early-stage: quartz-molybdenite±K-feldspar±pyrite veins associated with potassic alteration, middle-stage: quartz±calcite±chalcopyrite±galena±sphalerite±molybdenite+pyrite veins in phyllic alteration and late-stage: quartz±calcite±pyrite veins associated with advanced argillic alteration. Three types of fluid inclusions in quartz distinguished were designated as L-rich L+V phases (Type-I), salt-bearing L+V+S (Type-II), and V-rich L+V phases (Type-III). FIs of the early and middle stages are predominantly Type-II and Type-III inclusions, whereas the late-stage minerals commonly contain Type-I inclusions. Homogenization temperatures and salinities of FIs trapped in the early-stage quartz range from 481 to 590 °C and 13.19 to 61.1 wt. %NaCl equivalent, respectively. FIs in quartz of the middle-stage yield homogenization temperatures (Th) of 310 to 460 °C, while halite dissolution temperatures are ranged from 264 to 430 °C, and salinities of 7.9 to 50.3 wt.% NaCl eq. Homogenization temperatures and salinities of FIs in calcite of the middle-stage are range from 270 to 420 °C, 3.4 to 49.1 wt.% NaCl eq. The late-stage homogenize at temperatures of 138 to 240 °C, and salinities of 0.9 to 6.5 wt.% NaCl eq. The δ 34 S H2S values (0.6 to 4.5‰) of sulfides (molybdenite, chalcopyrite, pyrite and galena) and the δ 18 O SMOW (6.9 to