Mesozoic Granitoids Constraints On Gold Mineralization In The Xiong’ershan-Waifangshan Region

The Xiong’ershan-Waifangshan region is one of significant gold metallogenic areas in China. We select the Huashan pluton, the Wuzhangshan pluton, the Heyu pluton, and the Taishanmiao pluton and typical gold deposits in the Xiong’ershan-Waifangshan region, determine the gold deposits’ ore-forming time, and constraint on gold mineralization. We achieved the following main results and understanding:(1) The Taishanmiao pluton can be devided into three phases: the coarse-grained granite, the coarse granite-porphyry, and the fine-grained granite, corresponding to their zircon U-Pb dating are 126 Ma,126.1±8.5Ma and 114.2±2.9Ma respectively.(2) This study suggests that the Huashan pluton, the Wuzhangshan pluton, the Heyu pluton and the Taishanmiao Pluton are from the same magma source and evolutionary trend. The Huashan pluton, the Wuzhangshan pluton and the Heyu pluton are I-type granites formed in the post-collision, and the Taishanmiao pluton as A-type pluton formed in the post-orogenic setting.(3) The Huaishuping gold deposit was fromed in transition from compression to extension tectonic environment. Before stage of gold mineralization is characterized by potassic alteration. Gold mineralization period contain three stage(sparse disseminated pyrite stage, quartz-pyrite veins stage, and polymetallic sulfide stage). After gold mineralization is mainly of quartz- carbonate veins.(4) We have proposed that plutons’ emplacement order indicates the Xiong’ershan- Waifangshan region’s tectonic environment entered transition from compression to extension since late Jurassic(about161Ma), and it last to early Cretaceous(about 126Ma). The region entered intraplate extension environment since emplacement of Taishanmiao pluton. Wuzhangshan pluton’s emplacement marked tectonic entering the stage of in favor of gold mineralization, Huashan pluton and Heyu pluton’s emplacement provided ore-forming fluids for gold mineralization, and the emplacement of Taishanmiao pluton marked the end of satge that in favor of gold mineralization.