Abstract:Jiaodong gold deposit area is the third largest gold deposit area in the world. The origin of gold has always been a hot topic in geoscience. The study of the genesis of contemporaneous magmatic rocks with spatiotemporal relationships with gold mineralization is an important direction in the study of gold sources. In this paper, selecting Huashan concealed rock mass in Weideshan period in southern Jiaojia gold deposit as the research object, petrography, Geochemistry and LA MC ICP MS zircon U Pb chronology and Sr Nd Isotope studies has been carried out systematically for the first time. It is showed that the lithology of Huashan rock mass is mainly composed of monzogranite, a high potassium calcium alkaline series of peraluminous granite, characterized by light rare earth enrichment, heavy rare earth element depletion, and europium negative anomaly. Its chemical characteristics are somewhat different from those of Zhouguan rock mass during the same period, with the characteristics of multiple batches of magma pulses during the same period. The U Pb age of LA MC ICP MS is (118.07±0.52) Ma, which can represent the crystallization age of the rock mass. The Sr value of the rock mass is 0.712189, indicating the involvement of mantle derived materials; And (87Sr/86Sr)i is 0.709729. The value of εNd(t) is 20.63, and the depleted mantle model age (tDM2) is 3808 Ma, indicating the involvement of the basement of Neoarchean Jiaodong group. The Huashan rock mass is of crust mantle mixing origin, which means that the mantle derived magma was initially subducted and mixed with the magma formed by the melting of the Jiaodong rock group in the lower crust, forming young intermediate acidic magma. The magma continued to invade and was formed by assimilation and contamination of Linglong period granite.
