Mesozoic Weideshan granitoid suite and its relationship to large‐scale gold mineralization in the Jiaodong Peninsula, China

Abstract

The Jiaodong Peninsula in China underwent ultrahigh pressure (UHP) metamorphism in the Triassic and extensive magmatism in the Jurassic–Cretaceous, resulting in the formation of large‐scale gold deposits. This makes it an ideal site to study the destruction of the eastern North China Craton (NCC) as well as regional gold mineralization processes. The Weideshan granitoid suite is widely distributed in the Jiaodong Peninsula, with geochemical and isotopic data indicating that it formed through migmatization of crust‐derived silicic magma and mantle‐derived intermediate magma. This makes it different from the Jurassic Linglong suite, and the Cretaceous Guojialing and Laoshan suites in the Jiaodong Peninsula, although they have evolutionary continuity. U–Pb age estimates, from SHRIMP and LA‐ICP‐MS zircon dating, suggest that the Weideshan granitoid suite formed between 118.0 and 110.5 Ma, around the same time as the Jiaodong gold deposit, suggesting that the ore‐forming event was enabled during the stage of magmatic activity that formed the Weideshan suite, rather than during that which formed the Linglong or Guojialing suites. The initiation of Late Jurassic to Early Cretaceous magmatism reflects a regional switch from a collisional system with crustal thickening (compression) between the NCC and Yangtze Craton (YC) to lithospheric thinning (extension) during the subduction of the Pacific Plate. The upwelling of the Weideshan suite and the relevant extension structures that developed during this switching process provided favourable conditions for large‐scale gold mineralization.