Astudy of Geological Characteristics and Ore-formation Type of Pb-Zn Deposit in the Central Part of Xunbei Basin

　　Astudy of Geological Characteristics and Ore-formation Type of Pb-Zn Deposit in the Central Part of Xunbei Basin
　　The central part of Xunbei basin is one of the important ore belts in Shaanxi province with superior metallogenic condition. In recent years, geologist have gradually found and accessed some lead-zinc deposits such as siren ditch, guanzi ditch, nansha ditch and yellow stone, ect. Topology of stay in Xunbei basin has becomes a prosperity ore concentration area. So it is necessary to increase the knowledge of metallogenic condition and law in lead-zinc ore, which is in the stratum of the topology of stay in Xunbei basin, and investigate the character and metallogenic condition in the main lead-zinc deposit.Through a comprehensive collection of information available in the Block Neodymium magnets North Basin, they worked with a systematic analysis and a geological study in the study area, then analyzed the features of the lead-zinc deposits in the central part of Northern Basin. Analysis its ore-control condition based on the features of lead-zinc deposit, and then discusses the reason of it in their study area.From the results, these lead-zinc deposits are mainly come from the the Silurian in Meiziya group, shuanghezhen Group and the water tunnel. The simple shape is stratified and stratoid beds with simple structure ores, monotone mineral composition, and rock alteration weak with asymmetric.The rock between the up and down deposits displays the property of continuous sediment http://www.999magnet.com and characteristics of sequences. There is a close relationship between formation of deposit and hot water sedimentary rocks, which mainly consist of albitite and cherts oriented. According to the study of mineral inclusions, the deposit for the main mineralization temperature is 225-275℃, which belongs to the low-temperature conditions. The mainly chemical composition of ore-forming fluids is K+,Na+,Ca2+,Mg2+,SO42-,Cl-,F-, and Na+> K+> Ca2+> Mg2+, reflecting the deposit is generated by thermal deposition or underground brine causes. REE and isotope studies show that mineralization metal elements are mainly from the underlying sediment column, and mineralization fluid is from the sea.Based on the results, we consider that the deposit in the study area is produced by the hot water sedimentary from the pieces of rocks. Hot water sediment mineralization is the main reason of lead-zinc deposit underneath the Xunbei Basin Paleozoic.