Study On The Gold Mineralization System In Xiejiagou-Shichengkuang Structure-magma Belt, Zhaoyuan, Shandong

Jiaodong gold deposit cluster in Shandong Province is the most important gold production base in China. Different from two famous gold deposit "Jiaojia deposit"and "Linglong deposit", Xiejiagou gold deposit, a large scale deposit found in 2002, was not located on the fault belt, but between Jiaojia fault belt and Zhaoping fault belt. Therefore, the investigation of Xiejiagou deposit is greatly advance on geological research and will enlarge our knowledge on exploration. Our study focused on Xiejiagou gold deposit. Xiejiagou deposit occurred in alteration granite and was controlled by brittle-ductility shearing belt. The age of main mineralization was from 115 Ma to 125 Ma. Mineralization type was divided into synshearing alteration type and sulfide quartz vein. Three kinds of ores, pyritization-pyrilic-phyllic alteration, multi-sulfide quartz vein and chalcopyritization-pyritization-pyrilic-phyllic alteration, formed in different mineralization periods. The alterations of wall rock related to mineralization were pyrilic phyllic, silicification, pyritization and so on. And the reason for alteration zoning was superposition of different kind of alteration. Several mineralization points have been founded in the surroundings of Xiejiagou gold deposit, such as Xiaosongjia, Baiheding, Beifengjia and Shanchenjia (still under investigation). According to macro-features on surface, it is believed that the deposit and all mineralization points were controlled by the same brittle-ductility shearing belt. Besides, magnetic anomaly research indicates that there occurred blind Guojialing type granite at the area. So we call it as Xiejiagou-Shichengkuang structure-magma belt. The study by CSAMT shows that the structure-magma belt was a low resistance geological body which was on large scale. According to deformation degree, alteration and mineralization forms of rock, Xiejiagou-Shichengkuang structure-magma belt is made up of Baiheding shearing belt, Xiejiagou shearing belt and Beifengjia shearing belt which were output parallel and controlled by the same stress field. Based on the integrated study on Xiejiagou gold deposit and other mineralization points, the Xiejiagou-Shichengkuang structure-magma belt was set up preliminarily in the paper after discussion on the basic elements of mineralization system. It was regarded that the coupling of different geological process was the key on regional setting for mineralization. The subduction of pacific plate was the main dynamic for tectonism and magmatism. The transfer of tectonic system provided benefic geological conditions for mineralization especially. Most of gold was from...