Mid-upper Devonian Series Of Mutonggou Deposit Genesis Analysis In Qinling Fen Zhen Subregion

Mutonggou Pb-Zn deposit lies in the north of East Qinling Hercynian-Indosinian fold belt and south of Shuibaigou-Tanjiazhuang anticlinorium of Fentai ore field, which is a typical medium sized Pb-Zn deposit in Qinling mountain. In the aspect of tectonic position, it lies in the middle of Fenxian-Zhenan subregion miogeosyncline in north of Qinling geosynclinal system. This article makes conclusions in the ways of studying deposit geology, thin section analysis, stable isotope geochemical characteristics of Mutonggou Pb-Zn deposit as follows:1. By the influence of fold structure and stratum layer, Mutonggou Pb-Zn deposit has characteristics that Ⅰore body has thick saddle and thin alar part and Ⅱore body hosted in Gudaoling formation and Xinhongpu formation in the ways of single tabular and layered.2. This article study the geological features ore deposit and make conclusions as follows: the ore body appears saddle, stratiform-like and lenticular; ore composition are sphalerite, galena, pyrite etc; mineral composition are quartz, dolomite and calcite etc; the ore has the formation of barred, infection, net vein and massive and has the structure of metasomatic, raspberry-like, cycle, skeleton crystal; surrounding rocks undergo alteration like silicification, iron carbonation and pyritization, which limited to mineralization zone; silicification, iron carbonation has close relationship to metallogenic.3. It can be infered that the lead of Mutonggou Pb-Zn deposit mainly come from upper crust and mixed with some mantle material by using lead isotope to draw lead composition model. It also can be proved that the formation environment of the ore is reducing environment by the low total rare earth, light ree enrichment, ratio of ∑LREE and ∑HREE, unconspicuous Ce negative anomaly and weaker europium anomaly.4. By studying on composition of S isotope, it showed that the outcome of δ34S changes between 4.3‰ to 13.2‰ and the average is 7.47‰ and the worst is 8.7‰, of which character reflect that the sulfur comes form deeper or mantel. And meanwhile without biological organic sulfur, It can be infered that the sulfur of sulfide probably comes from the mixture of reduced sulfur of sulfate in seawater and deep sulfur.5. By the comparative and comprehensive analyse the character of Mutonggou Pb-Zn deposit and MVT and SEDEX deposit, we analyse that the deposit type belongs to exhalation sedimentary type.