Tectono-geochemical Exploration Model And Its Application In The Fulaichang Lead-Zinc Deposit,Northweastern Guizhou

The Fulaichang lead-zinc deposit is located in southwestern Yadu-Mangdong Pb-Zn Metallogenic belt in northwestern Guizhou,China,which is strictly controlled by structure and is suited between the Tianqiao lead-zinc deposit and the Maomaochang lead-zinc deposit.In this paper,on the basis of predecessors'research,under the guidance of tectono-geochemical exploration technology,and Theory and Method of Ore-field Geological-Mechanics,based on a large scale structural measurement,typical tectonic geometry,mechanics,kinematics analysis and tectonic rock characteristics,division of structural system,ore-controlling tectonic pattern are studied,then the structural ore-controlling regularities have been summarized,and metallotectonic system and structural ore-controlling model have been established.By the fine structural anatomy,the distribution characteristics of tectono-geochemical anomalies have beendiscussed,so as to infer the migration direction of the ore-forming fluid,establish the model of tectonic geochemical exploration,summarize the ore prospecting prediction signs,and delineate the key ore prospecting target areas.The main results are as follows:1.3 tectonic systems,including NE tectonic belt,NW tectonic belt and SN tectonic belt,have been identified and maybe correspond to the Hercynian to the early-mid Indosinian,the late Indosinian to early Yanshanian,the mid-late Yanshanian and himalayan epoch.The checkerboard structure controlling deposit,and the“xi-type”,and lambda–type structures,controlling ore bodies have furtherly been put forward,then the NE structural belt is major metallogenic tectonic system.The structural ore-controlling regularities have been summarize,and its ore-controlling model has been constructed.2.Data of 256 samples in mining area were carried out by mathematical statistics method.The results of the clustering analysis show that these elements maybe divide into five combinations:(1)Al₂O₃,K₂O,TiO₂,Hf,REE,Ga,Rb,Ba,Co,Sc,W and Sn,representing the combination of stratigraphic elements;(2)TFe,Cr,Ni,V,Mo,Tl,U,Cu,In,Na₂O,Zn,Pb,Cd,As,Sb and Hg represents a element combination of mineralization;(3)Li,Cs,Th,Be,Ge,Zr,Nb,Ta and Bi,its geological significance is unknown;(4)CaO,Sr and(5)MgO,MnO,respectively represent the element combinations of calcilization and dolomitization.The results of the factor analysis show that there are 7 factors in this mining area.There are:F1 factor(Nb,Sc,Th,Ga,Sn,Cs,Rb,Be,Zr,Li,Hf,In,W,HREE,Y(LREE),Ti O₂,Ta and Cr,Co,V)on behalf of the elements combination of the strata;F2factor(Zn,Pb,Hg,Cd,Mn O,Na₂O,Sb,As,Ge,(In))on behalf of the element combination of mineralization(element combination of near-ore halo and front-halo);F3 factor(Sr,Cu,Ca O,P₂O₅ and Mg O style),representing the element combination of dolomitization alteration;F4 factor(LREE,Al₂O₃,K₂O,HREE,TFe,Ti O₂,Y,Cr,Zr,V,Rb,Cs,Be)its unclear ignificance;F5 factor(Mo(U,TFe),Ca O),representing the element-combination of medium-high temperature hydrotherm(elements combination of tail-halo);F6 factor(Ni,Co)on behalf of the element combination of pyritization;F7 factor(Ba,Ti O₂),representing the element combination of baratization.3.Based on the tectono-geochemical geological map,the characteristics of the tectono-geochemical field in the mining area have been discussed.It is inferred that the migration direction of the ore-forming fluid is from the northeast-trending to the southwest-trending,and the ore bodies strike roughly the northwest-trending.4.The study summarizes the ore-controlling rules of structure,and summarizes the ore-prospecting criteria,which provides an important basis for the prediction of concealed ore deposits in the area,There are four target areas of one type,and further delineates two types of ore-prospecting prediction target areas.4.The study summarizes the ore-controlling rules of structure,and summarizes the ore-prospecting criteria,which provides an important basis for the prediction of concealed ore deposits in the area,and further delineates three types of ore-prospecting prediction target areas.