POSSIBLE SOURCE OF SULFUR IN THE PORPHYRY CU-MO ORE-MAGMATIC SYSTEM: EVIDENCE FROM THE ZHIREKEN DEPOSIT, EASTERN TRANSBAIKALIA

Abstract

Large porphyry Cu–Mo deposits containing hundreds of million tons of ore with high S/(Cu + Mo) values within commercial ore stockworks are surrounded by wide (up to 0.5 km or more) pyrite halos. Thus, such deposits represent a giant sulfur reservoir in the earth’s crust. Therefore, deciphering their genesis provides insight into the source of sulfur. This primarily concerns deposits related to the evolution of ore-bearing granitoid-dominated porphyry complexes. As was reported in [1–5 and others], the granitoid magmas of some porphyry Cu–Mo ore districts have sulfur contents that are too low (only up to 100 ppm) to provide a complete sulfur balance in the ore-magmatic system.