Geological And Geochemical Characteristics Of Iron-copper Deposits In Lushan Area, Weining,Northwest Guizhou

In the paper, this study area in the Lushan, weining, northwestern of Guizhou, take Iron-copper Deposits in Ore-bearing rock series between the top of the Permian Emeishan basalt group and the bottom of the Permian xuanwei group as the research object. Used in a variety of theories and methods of the stratigraphy, mineral petrology, structural geology, ore deposit geochemistry, element geochemistry. Study regional geological background, geological features of the mining area, the composition of ore-bearing rock series, the geochemical characteristics of deposit,ore, mineralogy and so on.Through the above research, the following conclusions:1.Through the study of mineral petrology characteristics shows that, ore-bearing rock series between the top of the Emeishan basalt and the bottom of the xuanwei group in the area has a close genetic relation with basalt rock, diagenetic material mainly from Emeishan basalt weathering products.2. The study of deposit, ore, mineralogy characteristics shows that, Iron and copper mineralization mainly are layered or like a layered, layer is produced in the red-brown volcanic breccia and light grey fine sandston, the characteristic of the sedimentology with iron copper deposit is obvious, the source of ore-forming materials shall be the homologous diagenetic material sources of ore-bearing rock series, mainly from the Emeishan basalt and volcanic tuff.3. SiO2is the main oxides on various of rocks, followed by Fe2O3, Al2O3.At the same time, K2O, MnO are low, TiO2is high, and ignition loss is higher. Besides basalt, other samples have lower MgO, Na2O and CaO.4. Trace elements Th, U, Be, Bi, Pb, Sn, In, Ag, Ta, Nb, Zr generally have gradually increasing trend according to basalt--tuff--clay rock--siltstone--volcanic breccias--fine sandstone, while the content of elements such as W, Ba, Sr in the basalt is significantly higher than other rocks, the content of elements such as Li, Hf in the basalt is significantly lower than other rocks,. Compared with the entire crustal abundance value, the elements such as In, Cd, Tl, Cs, Ag are characterized by features of loss in all kinds of rocks, Among them,In, Cd element loss is obvious;W, Ta, Hf, Zr, Nb are characterized by features of enrichment.5. The overall trend of the change of rare earth element content:the content of REE in volcanic rock is lower than Sandstone and mudstone, volcanic breccia has the lowest REE, the∑REE,∑HREE,∑LREE of tuff, basalt are medium, at the same time, the∑REE,∑LREE of clay rock are higher than sandstone, the∑HREE of clay rock is lower than sandstone. Overall, the characteristics of REE of ore-bearing rock series and deposit are the same as rock basalt,∑LREE>∑HREE.6. The iron-copper deposits in the Lushan, weining, northwestern of Guizhou area shall be epigenetic enrichment after the Syngenetic sedimentary. The formation of the iron-copper deposit is not only related to the sedimentary diagenesis, but also related to the underground hydrothermal activities after volcanic period, the underground hydrothermal after the volcano lead to enrichment.The following main results:1. The former generally believed that iron-copper deposits in the area belong to weathering crust type deposits; I think that iron-copper deposits in the area have obvious sedimentology characteristics, so, it shall be the epigenetic enrichment iron-copper deposits after the Syngenetic sedimentary.2. Put forward the formation of the iron-copper deposit that is not only related to the sedimentary diagenesis, but also related to the underground hydrothermal activities after volcanic period, the underground hydrothermal after the volcano lead to enrich.