Integrated Information Prognosis Of Xiaohongshilazi Pb-Zn Deposit In Jilin Province

The Xiaohongshilazi Pb-Zn deposit is located in the eastern part of the Central Asian Orogenic Belt between the Siberian Craton and the North China Craton,and the southern margin of the Songnen Block.Since the late Paleozoic,it experienced a complex tectonic setting that the closure of Paleo-Asian Ocea,post-orogenic extension environment and the subduction of Paleo-Pacific Plate.The study area has good metallogenic potential and occurred a variety of deposits.Based on theories of geological anomaly metallogenesis and integrated information prediction,this paper is started by metallogenic geological background and geological characteristics of Xiaohongshilazi Pb-Zn deposit.We analyzed the main ore-controlling factors and geological conditions of Pb-Zn deposit.Accroding to interpretation of integrated information on existed geochemical and geophysical data,the prospecting information is extracted by geophysical and geochemical information.On this basis,the prospecting model has been established,and the study on metallogenic prediction is carried out,and then metallogenic prediction area has been delineated to indicate the direction for further prospecting.The outcropped strata in the area is Early Permian Daheshen Formation.The intrusive rocks are mainly composed of Mesozoic diorite porphyry and granite porphyry.The faults are intensively developed in the study area,and the NS-trending fault is the main ore-controlling structure.The ore bodies occurred as layered and veined,and hosted mostly in dacite tuff,dacite breccia,andesite tuff,argillaceous slate and interlayer fracture zone.The mineralization is divided into hot water eruption stage,medium-low temperature hydrothermal stage and supergene stage.The wallrock alteration is mainly composed of chloritization and carbonatization.Silicification and sericitization are locally developed,and limonitization is developed on the surface.Silicification,pyritization and chloritization are important geological prospecting indicators.Integrated analysis shows that ore genesis of the deposit is hydrothermal exhalation sedimentary superposed by the hydrothermal.Achievements of high-precision magnetic measurements are processed by methods of polarization,ontinuation,horizontal first-order derivation and vertical second-order derivation.Anomalies of high-precision magnetic measurements and polarization anomalies in the mining area indicate that the study area is background for a large area of negative anomaly field and positive anomalies are predominantly in the central and southeastern regions.Based on the results of high-precision magnetic measurements,7 annular structures and 12 fault structures(physical structural planes)are obtained in the mining area.The fault structures are mainly composed of the NS-and NE-trending structures,which constitute the basic tectonic framework of the study area.The output and distribution characteristics of orebodies are controlled by the intersection of NS-trending faults and annular structures.The results of IP measurements indicate that low resistivity and high polarization are important indicators of electrical prospecting.The results of interpretations for soil geochemical measurements in the mining area show that Sb,Ag,Pb and Zn elements in the study area are highly concentrated,with a large coefficient of variation and good metallogenic potential.According to the results of cluster analysis and factor analysis,Pb and Zn are characterized by two-stage metallogenesis.Metallogenic element assemblages are composed of Au-Pb-Ag-Sb-As-Sn and Zn-Mn-Cu,which indicate Pb and Zn are products of different metallogenic stages in this area,and the mineralization is well developed in the overlapping area.Meanwhile,Pb,Zn,As,Sb,Ag and Cu are indicative elements for prospecting of Pb-Zn deposits in the area.10 Pb anomalies,5 Zn anomalies and 5 combination anomalies are delineated.Ht-4 combination anomaly with multiple concentration centers of Pb and Zn anomalies is the main ore-forming anomaly in the mining area.The existing Pb-Zn orebodies in the mining area occur within the anomaly,and the areas where no ore bodies and mineralization have been found still have good ore-forming potential.On the basis of the work mentioned above,an integrated information prospecting model is established.According to the favorable degree of metallogenic geological conditions and the development degree of integrated information prospecting indicators(geology,geophysics and geochemistry),integrated information mineral prediction research is carried out.Three metallogenic prognostic areas are delineated,and their prospecting potential is evaluated,which points out the direction for the follow-up prospecting work deployment.