Study On Geological Characteristics And Genetic Mechanism Of The Depth Of Shuiwangzhuang Gold Deposit In Jiaodong Peninsula

The Shuiwangzhuang gold deposit locates in the northwest of the Jiaodong Peninsula and is affiliated to Zhaoyuan City,Shandong Province.Geotectonic ally locates in the northwestern part of the Jiaobei uplift area on the southeastern margin of the North China Craton.The deposit is controlled by the NEE to the potouqing fault.It is a very large gold deposit discovered in the Linglong gold ore field in recent years.This work mainly studies two ore bodies No.2 and No.53.The types of ore include three types:disseminated-fine veined-vein-like pyrite.The ore structure is mainly composed of Self-form Semi-self-shaped structure and fragmentation structure.The ore structure mainly includes disseminated structure,fine vein structure and network vein structure.The ore body is present in the tectonic altered rock belt.The deep part is mostly vein-like veins,fine veins are disseminated and fine veins are dominant,and the main gold-bearing minerals are pyrite.The occurrence of gold minerals mainly includes three types:inclusion gold,gap gold and crack gold.The sulfur isotope composition of the pyrite in Shuiwangzhuang gold deposit shows that the?³⁴S of the deposit is between+7.0‰and+8.5‰,the range is 1.5‰,and the average value is+7.7‰,which is characterized in high?³⁴S and isotopic composition.The distribution is concentrated and the degree of homogenization is high.The sulfur source may be mainly from the source of the sulphur and mixed with a small amount of shell-source sulfur.The hydrogen-oxygen isotope composition of quartz shows that?D_V-SMOW=-91.7‰^-82.6‰,the average value is-87.6‰,?18O_V-SMOW=9.5‰¹2.6‰,the average value is 11.3‰,the corresponding oxygen isotope composition in water?¹⁸O water=1.8‰⁴.9‰,the average value is 3.6‰,?¹⁸O-?D diagram shows that the ore-forming fluid of the Shuiwangzhuang deep gold deposit is mainly magmatic water,and shows a trend of drift to the atmospheric precipitation evolution line,indicating that there is an atmosphere in the later stage.Mixed in precipitation.The fluid inclusions of the deep gold deposits in Shuiwangzhuang can be divided into four categories:H₂O two-phase inclusions,H₂O-CO₂ two-phase inclusions,H₂O-CO₂three-phase inclusions and inclusion mineral inclusions.The inclusion size is 3?m^Between20?m,mainly concentrated in 12?m¹8?m,the uniform temperature is between 120°C⁴10°C,mainly concentrated between 290°C³50°C,and the salinity is between1.0%¹3.8%,mainly Concentrated between 4.0%and 8.0%,the whole is characterized by medium and high temperature and low salinity.Multiple types of inclusions coexist in the same fluid system,indicating that immiscibility?phase separation?or boiling of the fluid leads to precipitation of gold.The Jiaodong area was in a strong extensional tectonic setting in Early Cretaceous,controlled by the subduction and retreat of the Pacific plate,accompanied by large-scale magmatic activity and strong crustal uplift.This hot-extension structure provides favorable conditions for the concentrated outburst mineralization of the large-scale gold mine in Jiaodong.The Shuiwangzhuang gold deposit is formed in the background of the structural transformation of extrusion to extension,and is controlled by the NE-oriented fracture in the region.The ore-forming materials and fluids exhibit the characteristics of the mixed source of crust and mantle,and the ore-forming fluid Immiscibility is the key to gold precipitation.