U–Pb and Re–Os Geochronology of Karamay Porphyry Mo–Cu Deposit in Western Junggar, NW China

Abstract The K aramay porphyry M o– C u deposit, discovered in 2010, is located in the W est J unggar region of X injiang of northwest C hina. The deposit is hosted within the K aramay granodiorite porphyry that intruded into E arly C arboniferous sedimentary strata and its exo‐contact zone. The LA‐ICPMS U – P b method was used to date the zircons from the granodiorite samples of the porphyry. Analyses of 12 spots of zircons from the granodiorite samples yield a U – P b weighted mean age of 300.8 ± 2.1 Ma (2σ). R e– O s dating for five molybdenite samples obtained from two prospecting trenches and three outcrops in the deposit yield a R e– O s isochron age of 294.6 ± 4.6 Ma (2σ), with an initial 187 Os / 188 Os of 0.0 ± 1.1. The isochron age is within the error of the R e– O s model ages, demonstrating that the age result is reliable. The R e– O s isochron age of the molybdenite is consistent with the U – P b age of the granodiorite porphyry, which indicates that the deposit is genetically related with an E arly P ermian porphyry system. The ages of the K aramay M o– C u deposit and the ore‐bearing porphyry are similar to the ages of intermediate‐acid intrusions and C u– M o– A u polymetallic deposits in the W est J unggar region. This consistency suggests the same geodynamic process to the magmatism and related mineralization.