Gold metallogeny in Iran; implications for gold exploration and conceptual modelling

Abstract

Significant progress in the classification, definition, and understanding of the main Au deposit types could significantly aid improvements in Au exploration. Because of the wide occurrence of Au in the central part of the Tethyan Eurasian Metallogenic Belt, Iranian structures composed of more than seventeen zones (arcs and blocks) are considered as having one of the largest Au reserves in the Middle East. Without attempts at understanding the tectono-magmatic evolution of Iran and the geodynamic settings of Au deposition, the establishment of a reliable predictive exploration model for Au-type deposits in Iran and other parts of the world will be unsuccessful. By considering, a total number of 33 Au deposits and prospects in Iran, a mineralization sequence is revealed from VMS, orogenic, Carlin-type, epithermal/ porphyry Cu-Au/ skarn, epithermal/ and IOCG, respectively. The trend of deposition gradually changes in the SW-NE axis to intrusion-related, epithermal, and porphyry Cu-Au deposits at UDMA and post-arc magmatism. Orogenic and volcanogenic massive sulfide (VMS) deposits occur adjacent to the northeast Zagros Fold and Thrust Belt, at the SSZ. The Zagros Orogeny and associated post-collisional magmatism at Urumieh-Dokhtar Magmatic Arc (UDMA) host many porphyry, epithermal, and intrusion-related Au deposits, with a major magmatism peak in the Miocene. The finding of the manuscript reveals that orogenic and Carlin-type Au mineralization are linked genetically. After each associated subduction for paleo-tethys (286-215 Ma) and Neo-tethys (210-68 Ma) in Iran, VMS and orogenic Au-deposits are formed in the border of the subduction (±obduction) zone. The porphyry, intrusion-related, epithermal, and IOCG mineralization are emplaced in appropriate formations and structures during collision and post-collision processes.