Geochemistry of Rhenium and Other Trace Elements in Molybdenite, Sar Cheshmeh Porphyry Cu‐Mo Deposit, Iran

Abstract

LA‐ICP‐MS analysis of molybdenite from the Sar Cheshmeh porphyry Cu‐Mo deposit (PCD), Iran, shows moderate concentration of Re (average ∼207 ppm) and low concentration of chalcogenides (average of Pb + Te + Bi, ∼31 ppm) as well as metalloids (average of As + Sb + Ge, ∼4.5 ppm). The early‐formed quartz–molybdenites associated with potassic alteration are characterized by moderately low concentration of Re (21–215 ppm with an average of 83 ppm), whereas the transitional quartz–molybdenite veins related to the sericitic stage of mineralization contain more Re (62–465 ppm, with an average of 207 ppm). In contrast, the late‐formed quartz–molybdenite veins associated with phyllic alteration show the highest concentration of Re (up to 1273 ppm with an average of 395 ppm). Gradual increase in Re content of molybdenites deposited throughout the evolution of the porphyry system is probably related to elevated ƒO2 and acidic conditions of the ore fluids governing the transitional and late stage of mineralization, when compared to the moderately low ƒO2 and basic conditions of the ore fluids precipitating the low‐Re molybdenites associated with potassic alteration. The mixed mantle/crustal source of the ore‐related magma and its fractionated composition in Sar Cheshmeh are consistent with magmatic conditions for the formation of Mo‐rich and Re‐poor PCDs in the world.

Magmatic‐hydrothermal Evolution and Mineralization Mechanisms of the Wangjiazhuang Cu (‐Mo) Deposit in the Zouping Volcanic Basin, Shandong Province, China: Constraints from Fluid Inclusions

“…These include similar alteration types, high temperatures (up to 466°C), highly oxidized ore-forming fluids (as indicated by the presence of hematite in fluid inclusions) and the stockwork-/ dissemination-type mineralization typically associated with porphyry deposits. It is also regionally linked to the volcanic formations that are common in porphyry systems (Sillitoe, 2010;Lan et al, 2018;Behnam et al, 2021;Yang et al, 2022;. However, its magmatic-hydrothermal processes cannot be well constrained by traditional porphyry models alone (Sillitoe, 1972;Mao et al, 2014;Lu et al, 2016;Yang and Cooke, 2019;Hou et al, 2020;Zhou et al, 2022), owing to the deposit's unique characters: (1) the deposit occurs in the intra-continental extensional environments and the Cu (-Mo) orebodies exclusively occur in the altered quartz monzonite but not as a calc-alkaline porphyry, which usually forms in the arc environment and is favorable for the production of porphyry Cu (-Mo) deposits (Sillitoe, 2010); (2) porphyry-type Cu deposits are scarce at the Luxi Block (Zhu and Sun, 2021), even in the eastern North China Craton (Yang and Cooke, 2019) where the metallogeny was widespread; (3) in addition to porphyrytype ore, the deposit also contains pegmatitic veins and cryptoexplosive breccia ore.…”