吉南太古宙岩群中的大型构造置换及其对BIF矿体的控制

LARGE-SCALE TRANSPOSITION IN ARCHAEAN ROCKS OF SOUTHERN JILIN PROVINCE AND ITS CONTROLLING EFFECT ON THE BIF ORE BODIES

以吉林省白山市板石沟铁矿区为典型实例 ,系统地论述了太古宙岩群中广泛发育的大型和区域性构造置换的几何特征和对BIF矿体的控制规律。本区构造置换主要表现为 :在紧闭同斜褶皱发育的持续变形过程中形成S1 ≈S0 ,并伴有钩状褶皱、石香肠构造和各类型线理的生成。按照主构造面均匀性法则 ,划分了构造均匀区段 ,并对其中 8个区段 (Ⅰ～Ⅷ )进行了详细的SFLπ组构分析。基于构造置换规律研究 ,提出本区褶皱轴与包络线双向找矿的理论与方法 ,经工程验证 。

The geometrical characteristics and its controlling effect on the BIF ore bodies were systematically described of a large scale tectonic transposition developed in the Archaean rocks in Banshigou Iron Ore Mine area, Baishan city, Jilin Province, where was taken as a typical example for studying the Archaean structures. The main feature of transposition, S 1≈S 0, was considered to be developed by progressive deformation during formation of the tight to isoclinal folds. The hook shaped folds, boudinages and lineations of many types were structures accompanying tectonic transposition. The homogeneous domains were divided within the typical area by considering homogenity of the main structural foliation, among these 8 domains (Ⅰ～Ⅷ) were selected for detailed SFL π fabric analysis. In looking for buried iron ore bodies, two direction (i,e along both the axial line and the enveloping line directions) exploration was theoretically and methodically proposed and generally in use in this mine, which showed a prominent economical advantages.