Ore-controlling Model Of Permeabilitystructures In Fault Zone,sanshandao Gold Deposit,shangdong Province,china

Sanshandao gold deposit is a typical super-large Jiaojia-type gold depositin Sanshandao-Cangshan ore controlling fault.It's not only an important gold industrial base,but also one of the prospecting and mineralization potential in China.The deposit is controlled by the fault structure,and there are still some differences in relationship between the fault zone and ore body and mechanism.The thesis focused on fault zone structure and its effects on gold mineralization.On the basis of detail field geological survey and indoor observation analysis,get the following understanding:(1)The fault zone of Sanshandao gold deposit has obvious zonation,which can be divided into four zones,the fault gouge zone,tectoniclens zone,dense joints and weak deformation zone.From the main fault to the outer,microstructure deformation from ductile brittle to brittle deformation,combined with EBSD,the fault gouge zone is divided into three layers.The deformation temperature is about 300~400°Ctectoniclens zone and dense joints zone with compressive shear environment;the temperatureof about 200~300°Cin weak deformation zone withtensile shear totension environment.(2)The ore-controlling mechanism of Sanshandao fault zone structure is characterized by horizontal zonation of mineralization-alteration.The types of hydrothermal alteration in the extruded schistosity zone are sericitization and sulfuration,and being as the pyrite-sericite-quartz type gold ore-bodies.The types of hydrothermal alteration in the joint zoneare the vein type of(pyrite)-sericite-quartz and silicification;the weak deformation zone are the potassium of fine vein type ore bodies.(3)According to the connectivity of the fracture,the permeability structure of the fault zone can be divided into three types: the backbone fracture,dangling fracture,isolated fracture,and with the evolution of mineralization,stress changes constantly,there three types of permeability structure can also be transformed into each other,which can provide the fluid migration and mineralization to provide adequate accesses and ore storage spaces.Estimate permeability of rocks in different alteration-zonation of early stage and main stage mineralization.Therefore,the permeability can be used as a prospector for the study of hydrothermal deposits.(4)Based on the characteristics of the permeability structure of the fault zone and the alteration-mineralization,the influence of the permeability on the thickness of the ore body is analyzed by regression analysis,the ore-controlling model of the structures in Sanshandao fault zone.