Characteristics Of Petrologic Geochemistry And Mineralization In Jiemeng Region, Northwestern Zhejiang

Jiemeng region is located in the Qinzhou-Hangzhou metallogenic belt. So far,there are only small mines in mining,due to only few works related metallogenic geological background and ore-forming regularity. In recent years,major breakthroughs were made in Panjia and Yinshan mine area,we have to think about:with similar ore-forming geological background and geological conditions of Jiemeng region covered with metallogenic prospects?Inorder to better understand mineralization of Jiemeng region,we combine Yanshanian magmatism,detailed petrology,rock geochemistry and chronology research,to comprehensively understand polymetallic deposit in this area and explore the relationship between Yanshanian magmatism of West Zhejiang and tectonic background with Jiemeng regional metallogenic process and characteristics of polymetallic deposits. Through the comparson Panjia,Yinshan mine areas with adjacent mining area to analysis of regional prospecting target and direction. The main achievements are as follows:1. Late Yanshanian granodiorite and Lantian formation are closely related to the lead and zinc polymetallic mineralization in this area,in which Lantian formation is the main mineral source bed and granodiorite is the main source of hydrothermal,at the same time provides a small amount of ore-forming materials; The Sinian system strata are fold strongly and the core is the main ore space.forming a layer-control type hydrothermal metasomatic deposit; While the contacted zone of Lantian formation stratum and granite diorite formed a skarn type deposit.2. The Chengjia,Yaojia granodiorites in Jiemeng region are belong to the alkali peraluminous high potassium calc alkali granite,formed in the environment of island arc or continental collision zone,being the product of late orogenic or syn-collisional period,and a deep molten lava formation of granite magma. The age of LA-ICP-MS zircon U-Pb are 142.0±.6Ma、146.3±1.2Ma,which was the transition period from the ancient tethys tectonic domain to the Pacific tectonic domain in the southeastern China,a double characteristics of extrusion stress and stretch stress of rock mass.3. Comparson Jiemeng region with Panjia and Yinshan mining area,they are have similar ore-forming geological background,mineralization process as two metallogenic period of hot water sedimentary period and magmatic hydrothermal alteration. The strata of Jiemeng region is relatively rich in Au,Ag,Zn elements,and this is the main prospecting target for hydrothermal metasomatic type and skarn type Au,Ag ore and Zn polymetallic deposits.4. Geophysical exploration results of Jiemeng suggest that the rock mass plunges toward the north west side of the mining area,deep in the rock mass contact zone develops by skarnization or pyrrhotite-bearing sphalerite body caused strong magnetic anomaly,the magnetic anomaly scale and intensity are higher,we infer that in the deep mining area is the most likely to find a certain size and mainly composed of sphalerite polymetallic skarn type mine.