Genesis And Metallogenic Prediction Of Kangshan Gold Deposit,luanchuan County,henan Province

Kangshan gold deposit is located in the southern margin of North China Craton and Xiong’er mountain gold-molybdenum polymetallic metallogenic belt.The tectonic development and magmatic activity in this area are strong,showing the complex metallogenic mechanism of the deposit and the characteristics of multi-stage magmaticstructural superposition mineralization.In this paper,Kangshan gold deposit is taken as the research object.Based on the study of existing geological data,the genetic mechanism of the deposit is discussed through the study of geology,geochemistry and ore deposit.Combined with the ore-controlling factors of the deposit,the spatial distribution characteristics of the ore body and the signs of element anomalies,the metallogenic regularity is summarized,the geochemical exploration model is established,and the metallogenic prediction is carried out,obtaining the following main understanding:(1)The Xiong’er mountain area experienced frequent Mesozoic magmatic activity and four large-scale magmatic intrusions successively.Based on zircon U-Pb isotopic chronology of subdike at different periods in Heyu rock mass,The time of magma intrusion is limited to >144.7Ma,138.0～134.5Ma,130.7～128.1Ma and 126.3～123Ma respectively.The rock mass was formed under the background of Mesozoic tectonic system transformation,and was the product of partial melting of crust-mantle material caused by lithosphere subsidence.(2)In-situ carbonatite laser U-Pb isotope dating technique was used to study the chronology of calcite veins of hydrothermal phase II in Kangshan gold deposit.The isotopic age of calcite veins is 46.3～45.4Ma,indicating that the gold deposit was affected by hydrothermal activity events accompanied by tectonic movement after the main mineralization event of Yanshanian,and its overall strength is weaker than that of Yanshanian.Although there may be local enrichment and mineralization,it is not the main prospecting direction in the area.(3)Through the study of rare earth elements,trace elements and isotopic geochemical elements in different geological bodies,it is considered that the oreforming fluid of the deposit not only inherits the deep magmatic hydrothermal fluid,but also has the metasomatism and superposition transformation of the hydrothermal fluid to the surrounding rock.The temperature of the fluid in the early stage of mineralization is high.As the mineralization continues,the temperature gradually decreases.The ore-forming fluid is generally characterized by a Cl-rich fluid system in a reducing environment.(4)On the basis of the study of structural characteristics,the "three-level structural ore control model" of Kangshan gold deposit is established.Among them,Class I eastwest fault structure controls the whole tectonic pattern of the region.Class II NE trending fault structure is the main migration channel of ore-forming fluid,which controls the spatial distribution of gold deposits or orebodies in the area.The orebodies controlled by this fault zone are dominated by altered rock type mineralization.The grade III fault structure is the secondary fault structure derived from the grade I and II faults.The orebodies occur mostly in the Grade II and III fault zone within the grade I fault fracture zone or at the intersection of faults.The orebodies controlled by the fault are mainly quartz vein type gold mineralization.(5)A comprehensive analysis of the genesis of Kangshan gold deposit,Among them,the source: the source of the immediate mineral originates from the deep source mantle.With the continuous upward invasion of the hydrothermal fluid,some surrounding rock substances are added in the upward invasion process.Transport: that is,fluid migration.Majaoying fault(I grade fault)and a series of NE trending faults(II grade fault)near the region are the main migration channels of hydrothermal fluids in the shallow part of the surface within the region and the mining area.Storage: that is,the occurrence and placement of ore bodies.The distribution of ore bodies is controlled by the three-stage structural ore-controlling mode,and the ore bodies mostly occur in the II and III grade fault zones within the I grade fracture zone,or in the intersection of faults and the unconformable contact surface of regional strata.In the whole metallogenic system,the subduction of the Pacific plate to the North China Craton is the basic driving force of the tectonic movement,magmatism and mineralization in the Xiong ’er mountain area during the Cretaceous period,and the main migration channel of magmatic-hydrothermal is also a large number of faults and tectonic fracture systems formed under the action of the intracontinental plate movement.(6)The delineation of the predicted target area and the verification of the exploration borehole.Through the study of the geochemical characteristics of the primary halo of the 210 ore body of the Kangshan gold mine and the fractal characteristics of the elements of the 803-1 ore body,the geochemical exploration model of the ore body was established.On this basis,combined with the study of ore genesis and metallogenic regularity,metallogenic prediction is carried out.This time,three grade I prediction target areas,one grade II and one grade III metallogenic prediction target areas were delineated.Among them,the prospecting target area was verified in the I-level prediction target area,several verification boreholes have been drilled.There are 53 figures,18 tables and 266 references in this paper.