Geological setting and geochemistry of the Güzelyayla (Maçka-Trabzon) porphyry Cu-Mo deposit pontid ne Turkey

Geological Setting and Geochemistry of the Güzelyayla (Maçka-Trabzon) Porphyry Cu-Mo Deposit, Pont id NE Turkey SUMMARY Within the framework of this investigation, the litholo- gic units exposed around the Zigana-Hamsiköy (Trabzon) area were investigated in relation to the stratigraphic locations, petrographical and petrochemical characteristics of the rock units. Furthermore, through obtaining data regarding the mi- neralogical and geochemical properties of the Güzelyayla por phyry Cu-Mo deposit, various interpretations have been drawn under the light of the data obtained. The basement of the study area consists of basalt, ande- site, diabase and their spilitized product which are Jurassic in age and are called Pontid Lower Basic Complex. This series is overlain by crystallized limestones commonly known as Berdiga Formation. The Bekçiler Formation, which is asserted to overlic discordantly these rocks, consists of ore-bearing dacite and the Dikkaya Dacite that lacks mineralization. This rock assemblage is of Cenomanian age, The Hamsiköy Sedimentary Volcanic Complex of Cenomanian age is composed of basalt, andesite and their pyroclastics, as well as the volcano-sedi mentary rocks which are observed as interbeds in these rocks. The Zigana Granitoid intruded, by crosscutting all the rocks already present, at the end of Cretaceous. The youngest units of the study area are dacite-microgranite dykes and traverti nes which are still being formed. The rocks belonging to the Pontid Lower Basic Complex are generally tholeiitic transiti onal to calc-alkaline in character and characterize an island-arc environment. Dacitic and basaltic volcanic rocks of Upper Cretaceous age, are also formed in a subduction zone and are calc-alkaline in affinity. The Zigana Granitoid is of I-type and calc-alkaline features and characterizes an island arc environment that is getting mature. The hydrothermal Güzelyayla porphypy copper-molydenum mineralization is porphyry copper in type formed as a conse quence of hydrothermal activity related to granitic intrusron in the area. The ore deposit is found in the Pontid Lower Ba sic Complex and the quartz microdiorites of the Zigana Grani toid and it is Stockwork and dissemineted in form. The argi- llic zone did not flourished in the deposit, while the potas- sic, phyllic and propylitic alteration zones were developed. The Güzelyayla porphyry Cu-Mo deposit is mesothermal in cha racter, and is formed between the temperatures of 280 and 460 °C. When the geochemical exploration data compared with those obtained from the drillings, it has been found Cu ano malies don't show the mineral-bearing zones, where as Mo anomalies indicate mineralization zones of high tenor values. In conclusion, the regional stratigraphic, petrographic, mineralogic, geochemical and petrogenetic properties for the porphyry type Cu-Mo mineralization are determined. VI