Petrogenesis and Tectonic Implications of the Ore-Associated Intrusions in Bayanbaolege Ag Polymetallic Deposit, Inner Mongolia, NE China

The large Bayanbaolege Ag polymetallic ore deposit is located in the Tuquan-Linxi Fe (Sn)-Cu-Pb-Zn-Ag-Nb (Ta) metallogenic belt, which an important part of Great Xing’an Range province, northeast China. sulfide–quartz vein-type orebodies are mainly hosted Cretaceous granodiorite porphyry and Late Permian Linxi formation. U-Pb dating zircon from post-ore diorite porphyrite yields age 124.8 ± 1.1 Ma, constrains mineralization time at Early Cretaceous. Sr-Nd isotope values (87Sr/86Sr)i = 0.708576~0.710536; εNd (t) −0.51~+0.69; Hf 176Hf/177Hf 0.2827278~0.2830095, εHf +3.1~+11.2, TDM2 615~1341 Ma porphyry. 0.2828596~0.2829451, +5.7~+8.8 porphyrite, 827~1108 indicating that ore-forming materials were possible involvement heterogeneous juvenile sources including moderately depleted mantle newly underplated lower crust. major trace elements (including REEs) implied these intrusions I-type granite linked intimately to westward subduction Paleo-Pacific Ocean plate. From whole-rock ages, as well Sr-Nd-Hf data, we conclude ore-associated granites formed extensional tectonic setting Cretaceous, compactly related retreat subducted plate rather than closure Mongol–Okhotsk Ocean. Furthermore, by integrating geological background work previous research work, implying should have been 125–130 Ma.