CONCENTRATION VARIATIONS OF MAJOR AND MINOR ELEMENTS ACROSS VARIOUS ALTERATION ZONES IN PORPHYRY COPPER DEPOSIT AT SUNGUN, EAST AZARBAIDJAN, IRAN

The porphyry copper deposit at Sungun is located in East Azarbaidjan, NW of Iran. The Sungun porphyries (Oligo-Miocene) occur as stocks and dikes and intruded a series of Oligocene pyroclastics and lavas, Eocene arenaceous-argillaceous rocks, and Upper Cretaceous carbonates. The porphyry stocks are divided into two groups, 1) porphyry stocks I (quartz monzo-diorite) and 2) porphyry stock II (quartz monzonite, granodiorite, and granite). Porphyry stock II hosts the copper and molybdenum ores. Numerous and various cross-cutting veinlets and micro-veinlets of quartz, sulfides, sericite, carbonates, and sulfates were developed in porphyry stock II. Three distinct types of hydrothermal alterations and sulfide mineralizations are recognized at Sungun; 1) hypogene, 2) contact metasomatic, and 3) supergene. The vertical variations in concentration of 12 elements (S, Cu, Mo, K, Rb, Ca, Sr, Na, Mg, Fe, Al, and Si) across various hypogene alteration zones at Sungun demonstrate that S, Cu, Mo, Fe, K, and Rb are mainly concentrated in the phyllic and potassic-phyllic zones where the abundance of Ca, Sr, Mg, and Na are appreciably low relative to the potassic zone. The values of Al and Si are relatively high in the supergene zones and their abundance gradually decrease downward toward the potassic zone. The copper and molybdenum are substantially localized in the phyllic and potassic-phyllic zones particularly in the central part of the mineralized porphyry stock where the rocks underwent severe stockwork-type fracturing and micro-fracturing. Their concentrations are relatively low in the potassic zone.