The Source Of Metallogenic Materials And Genesis Of The Henglingdi Copper Deposit In Zhongtiao Mountain Area

The Henglingdi Sigou copper deposit belongs to Henglingguan type copper deposit,which is located in the north of Zhongtiao Mountain metallogenic belt.Although research regarding to the Henglingguan type copper mine started early,there are still some weak points needed to solve,such as the lack of a systematic summary of the geological characteristics of henglingdi copper mine,the metallogenic age,the source of ore-forming materials,the type,nature,source and enrichment mechanism of ore-forming fluids.On the basis of field investigation,fluid inclusion characteristic observation,sulfur and lead isotope geochemical and metallogenic geochronological study,this thesis carried out a detailed study on the geological characteristics,metallogenic materials and fluid sources,metallogenic age,and genesis of the deposit.The main conclusions are as follow:(1)The mineralization process of henglingdi Sigou copper deposit can be roughly divided into two stages and three stages.They are early sedimentary diagenesis,star point mineralization,metamorphic hydrothermal quartz sulfide and calcite quartz sulfide.The Ar-Ar dating results of altered biotite in the surrounding rock of the chalcopyrite quartz vein indicate that the mineralization of Henglingguan copper deposit occurred in 1.83 billion years,which may represent the main mineralization event.(2)Fluid inclusion observation and H-O isotope analysis shows that the ore-forming fluids during the metamorphic hydrothermal stage consists of metamorphic fluids with medium to low temperature and high salinity at the earlystage.Fluid boiling leads to the precipitation of a large volume of metals in form of sulfides.Due to subsequent mixture with meteoric fluids with lower temperature,ore-forming fluids are characterized by medium to low temperature and low salinity atthe late stage.Calcite and quartz sulfide vein formed during this stage.(3)Sulfur and lead isotopic compositions show that the main source of sulfur of the Henglingdi and Sigou copper deposits is biogenic,but a small amount of sulfur was derived from mantle magma.Lead in the ore,except for a small proportion from country rocks,is mainly derived from deep crust,which may be related to the mafic intrusions along the fault.(4)A comprehensive study shows that the genetic type of the Henglingdi and Sigou deposits are sedimentary metamorphic copper deposit.