扬子地块西南缘区域成矿的大地构造背景和矿床形成的构造控制

GEOTECTONIC SETTING OF REGIONAL MINERALIZATION ON THE SOUTHWESTERN MARGIN OF THE YANGTZE TERRAIN AND TECTONIC-CONSTRAINTS ON THE FORMATION OF ORE DEPOSITS

扬子地块西南缘正处在欧亚板块，印度板块和太平洋板块等三大板块的复合部位，其大地构造经历了前震旦纪、震旦纪至三叠纪和侏罗纪至第四纪等三大演化阶段。其发展演化导致该区沉积岩和岩浆岩中含有多种丰度较高的成矿元素，并在构造发展演化过程中，促使成矿元素活化、迁移、多次叠加富集，形成具有工业价值的金、银、铜、铅锌、汞锑等贵金属和有色金属的低温矿床成矿域。它们在时间上和空间上均呈现有规律的分布，并明显受地层、岩性、岩相和构造控制。特别是受构造控制更加明显，具多级构造控矿的特点，通常一级构造控制矿带；二级构造控制矿田、矿床；三级构造控制矿体的形态和产状。

The southwestern margin of the Yangtze terrain is located in the conjunction area of the Indian plate,the European-Asian plate and the Pacific plate,and it has undergone three developing stages:Pre-Sinian,Sinian to Triassic and Jurassic to Quaternary. Its development and evolution also caused the high concentration of ore-forning elements in sedimentary rocks and magmatic rocks in this region,thus leading to the mobilization,migration and enrichment of ore-forming elements during the process of tectonic evolution. As a result, precious metal deposits of Au, Ag,Cu, Pb, Zn,Hg,Sb,etc. were formed. These deposits showed regular distribution in space and time,and were controlled mainly by strata, lithological character, lithological facies and structure in particular,showing the characters of multiple tectonic-controlling. Generally,ore belts are controlled by main structures, orefields and ore deposits by secondary structures, and the forms and occurrences of orebodies by third-ordered structures.