On Tectono-Fluids-Metallogenic System Of Gold Ore Fields Of The Western Henan

The Western Henan, situated in the Hua-Xiong massif of the southern margin of the North China Platform, is of typical basin-range structure. Outcropped rocks include Archean granites and greenstones of Taihua group, Proterozic vocanics and sedimentary rocks and Cretaceous-Tertiary fliuvial-lacustrine facies sedimentary rocks ect. Gold deposits are genetically closely related with the Yanshanian granites.Au, Mo mineral resources are abundant in the Xiaoqinling, Xiaoshan, Xiongershan and Waifangshan gold ore fields etc. Large amount of gold accumulated in tens of gold-concentrated regions. Their ore-forming elements, deposit types and mineralization stages are comparable. Ore-forming processes were controlled by the same thermo-tectonic events.On the basis of the outstanding difference of crustai thickness between the lifted block regions and the fault basins, with deep faults (marginal fault) as the boundary of lifted block regions and basins, the boundary faults corresponding to the mantle slopes, the crust-mantle mix-melting origins of the magmatism and the modern geothermal activities of the Mesozoic Yanshanian lifted block regions and basins, and the fault basins subsided in the Cretaceous-Tertiary period, the author has considered that the basin-range structure of this region is the result of the long-lasting activities of the synsedimentary faults that were caused by the melting of materials close to the crust-mantle boundary and the lateral intrusions of the magma, the nonuniform rolling of upper mantle, and chilling of magma as well as volume contraction in the Mesozoic-Cenozoic era.According to ore-forming concentrated province of Au-Ag-Pb-Mo deposits has a close spatial relationship with Mesozoic upwarping faulted region and fault basin, Yanshanian granite bathblites and small granite-porphyry bodies, characteristics of ore-forming fluids and the regional fluid alteration results,the results of isotopic analyses revealing that the ore fluids were mainly derived from a mixed source ofMesozoic Yanshanian magmatism and meteoric water, mix sources of sulfur, the deep igneous origincharacteristics of lead and carbon, and the coincidence of the mineralisation, granitoid magmatism, fault-lifting and the basin development, the following conclusions can be drawn.The vertical zoning of gold deposits can be subdivided into four zone types: (1) the deep zone-gold-quartz vein type, controlled by ductile-shear zone within the Taihua group (Xiaoqinling-type); (2) the middle zone-the Xiaoqinling-type and the Jiaojia-type gold deposits, the later controlled by fracture zones within the vocanics of the lower covering strata Xionger group of Proterozic and occurred in altered rocks (Xiaoshan -type); (3) the shallow zone-Jiaojia-type gold deposits and explosion breccia-type gold deposits (Xiongershan-Waifangshan-type) and (4) the top zone-the polymetallic deposit type and few gold deposits controlled by fracture zones within the sedimentary rocks of top covering strata of Proterozic and occurred in altered rock.(Luanchuan-Lushi-type). The different gold deposits occurred in the western Henan actually reflect different exhumations at different sites.The gold deposits in the area are products in the development of the Yanshanian basin-range tectonic regime. The mineralisation energy were mainly derived from the tectono- and magmatic thermal activities. The ore-forming fluids are deep-circulated meteoric water and magma fluids. The ore substance was mainly derived from Mesozoic Yanshanian granitoids probably derived from the melting of mantle-crust mix, and minor derived from the Mesozoic basins and other crystalline basement rocks. The deep fault zones (marginal fault zone), the boundaris of lifted block region and basin, as well as their fault-fissure network are the ore fluid channel ways and ore-forming spaces.The metallogenic system can be classified as the deep-circulating fluid from the basins and magmatic solution metallogenic system under the tectonic dynamic regime of the basin-range system i...