李坝金矿田构造地球化学特征及其找矿意义

本文从野外地质实际出发 ,系统研究了区内广泛发育的断裂构造特征及其与金矿化的关系 ,将断裂分为三级 , 、 级断裂主要为导矿和配矿构造 ,NW、NWW向的 级断裂为最有利的赋矿构造。据此 ,以构造地球化学的观点为指导 ,借助计算机化探数据处理系统 ,对系统采集的构造地球化学样品的 17个元素分析成果进行系统研究和 R型聚类分析等处理 ,将构造与金矿化的关系转化为构造地球化学特征 ,进而转化为找矿指标。研究表明 :含矿 (赋矿 +矿化 )断裂的特征元素组合为 :Au、Ag、As、Sb、Pb;非矿断裂的特征元素组合为 :Cr、Mn、Ti、V。将已知的赋矿、矿化和非矿断裂作为母体 ,利用多类判别分析建立了非矿、矿化和赋矿断裂判别函数 ,对已知的 2 3条断裂进行判别分类 ,错判 3条 ,准确率为 87%。该成果已应用于实际找矿工作中 ,通过对 11处未知区构造的含矿性研究 ,系统采取构造地球化学样品和进行相应的多元素分析 ,经判别后指导找矿 ,共发现金矿体三条 ,矿化体五条 ,取得了良好的找矿效果

TECTONIC GEOCHEMISTRY OF THE LIBA GOLDOREFIELD AND APPLICATIONS FOR PROSPECTING

Based on our field geological investigation, features of pervasive faults in the Liba orefield and the relationship between faults and gold mineralization have been studied in this paper. Faults can be divided into three stages: Ⅰ , Ⅱ and Ⅲ. Stage Ⅰ and Ⅱ are conductive and auxiliary structures, while faults of stage Ⅲ in NW and NWW directions are the best structures related to gold orebody among them. Furthermore, guided by views of tectonic geochemistry, the relationship between faults and gold mineralization has been transformed into characteristics of tectonic geochemistry and further into prospecting criteria and analysis results being processing by data processing system of geochemical exploration. It shows that Au, Ag, As, Sb and Pb association of faults is related to gold mineralization by means of systematically collecting tectonic samples, of which 17 elements were analyzed and related to gold orebodies, but Cr, Mn, Ti and V association of faults is not related to gold mineralization. Three discriminant functions of faults not related to/related to/gold mineralization and to gold orebodies have been built respectively with the method of multivariate discriminant analysis and on the basis of using three types of faults known above as standard samples. 23 known faults have been reclassified by discriminant functions, only 3 of which got wrong classifications. The rate of discrimination is close to 87%. By the practical use of such a method, 3 gold orebodies and 5 gold mineralized bodies among 11 fresh faults have been discovered in the Liba orefield.