[S-CG61_2AM2] Petrology, Mineralogy and Resource Geology

[SCG61-12] Assessment of Nakhile porphyry Cu mineralization potential using geological, geochemical and statistical studies: a case

*Mohammad BOOMERI¹, Kazuo NAKASHIMA², Yavari F¹ (1.Univ. of Sistan and Baluchestan, 2.Yamagata Univ.)

The Nakhile Cu mineralization is located in 145 km northwest of Zahedan in Sistan and Baluchestan province of Iran. This area is geologically located in boundary part of Lut block and flysch zone of east Iran. Geology of the study area consists of Cretaceous to Eocene andesitic lavas and tuffs that were intruded by a dioritic to quartz-dioritic stock. The intrusive rocks are mainly altered and mineralized. Based on the petrography and XRD studies, main mineral in all types of the igneous rocks is plagioclase and the main texture is porphyry. Other minerals are clinopyroxene, amphibole, biotite, quartz, and secondary minerals that vary in the igneous rocks. A large part of the intrusive rocks is rich in pyrite. The pyrite occurs as veins, veinlets and disseminated in the stock. Cu mineralization occurs as vein and can be divided into hypogene and supergene mineralization. Hypogene mineralization is characterized by chalcopyrite and pyrite while supergene mineralization is characterized by malachite, azurite, jarusite, ghothite, hematite and limonite. The propylitic alteration is dominant feature of the intrusive rocks as a wide outer zone. Potassic, phyllic and argillic alterations are also important in the area. The potassic alteration is probably important in the center part of the stock in depth. phyllic and argillic alterations are mainly formed by supergene processes.The samples that were collected from the least altered and altered rocks in the study area were analyzed by ICP were processed by convenient software such as EXEL and SPSS to obtain statistic parameters of: skewness, maximum, minimum and standard deviation. Then, the histograms for the amount of Cu, Au and related elements were drawn and their correlation coefficients were calculated. There are remarkable positive correlations between Cu, Au and Ag indicating their similar origin. The highest content of Cu is 7000 ppm in the study samples. The Cu anomalies are mainly observed in central and eastern parts of the area. The highest content of Au is 6000 ppb. The Au anomalies are mainly observed in western parts of the area. The higher contents of Pb, Zn and Ag are observed more away from the intrusive rocks. The outcrops in the area are mainly similar as propylitic alteration zone of porphyry Cu deposits that is characterized by secondary hydrothermal epidote and chlorite and pyrite. The Cu porphyry mineralization and other alteration zones specially potassic probably occur in depth in the area.