MINERALIZATION AND METASOMATITES ZONING IN PORPHYRY СOPPER DEPOSITS OF GOSHGARCHAI ORE MAGMATIC SYSTEM (LESSER CAUCASUS, AZERBAIJAN)

Abstract

The Purpose of the paper is to analyze the zoning nature of mineralization and metasomatites in the known porphyry copper deposits of the Goshgarchai ore magmatic system (OMS) associated with the Murovdag group of intrusives. The Methods used in the study include complex structural and geological, metallogenic, geological-petrological, ore metasomatic and petrochemical parameters of metasomatites as well as the studies that take into account science-based geological prospecting works carried out earlier. There is some regularity between the petrochemical parameters of metasomatites and the contents of copper and molybdenum. Results. It has been found that the thickness of methasomatically altered rocks varies from several meters to tens and hundreds of meters (in the intersections of multi-oriented faults) within the Goshgarchai OMS. Their length ranges from 500-1000 m to 2000-3000 m. Three gradually changing each other elliptical metasomatic zones are distinguished around the ore generating intrusives of the Goshgarchai OMS. They border the intrusive massif of porphyry composition. The inner zone including the endocontact and apical parts of the porphyry intrusive is represented by strongly silicified rocks, which are almost completely transformed into secondary quartzirtes. The middle zone is determined as quartz-sericite-chlorite facies of secondary quartzirtes. The third external zone of the metasomatic column is represented by the propylite facies of secondary quartzirtes. Conclusions. Having studied ore zoning within the borders of the Goshgarchai deposit we have obtained the following series of vertical zonality of elements (bottom-up): Mo→Cu→Со→Ni→Cr→Ag→Pb→Zn. Hydrothermal metasomatic variations of enclosing rocks in the zones of different types of metasomatites generated under deposit formation have been studied and compared on the basis of petrochemical data.