滇黔桂湘地区中生代复合大陆动力成矿系统特征

FEATURES OF METALLOGENIC SYSTEM OF COMPOUND CONTINENTAL DYNAMICS IN YUNNAN-GUIZHOU- GUANGXI-HUNAN PROVINCES

通过大陆构造地质研究和分析认为在印支期SW→NE挤压构造应力场的驱动下,本区沉积盆地内可能形成自SW→NE向的盆地流体大规模流动(滇东南→桂西北)。在燕山早期,环太平洋板块自SE→NW挤压构造应力场驱动下,本区可能形成自SE→NW向的盆地流体大规模流动(桂东南→黔西北→滇东北),且可能被限定在康滇断块隆升区西边界的以东地区。在燕山晚期,伴随大陆构造进入伸展-走滑体制和山间断陷盆地的形成,幔源热物质侵位形成盆地流体的垂向热(流)应力驱动源,这种张剪性构造为流体成矿提供了良好的构造背景。古潜山、褶皱-断裂带、逆冲断裂-褶皱带和脆韧性剪切带可能是本区主要流体圈闭构造和矿床定位构造,成矿系列可划分为改造型拉分盆地中古潜山控制的F-Fe-S-Sb-Au成矿系列、褶皱-断裂带热水再造成因的Sb-As-Hg-Au成矿系列、改造型盆地边部逆冲断裂-褶皱带中热流体成因的Ge-Ag-Pb-Zn成矿系列和脆韧性剪切带中W-Sb-Au成矿系列。

Based on research and analysis of continental tectonics, it is proposed in this paper that the basinal fluids, migrating from the southwestern part of the basin （southeastern Yunnan） to the northeastern part of the basin （ northwestern Guangxi） and driven by NE-directed tectonic compression field during the Indosinian orogeny, might be at large-scale, and the basinal fluids, migrating from the southeastern part of the basin to the northwestern part of the basin and driven by northwest-directing tectonic compression field derived from the western margin of the Pacific Plate during the early Yanshanian orogeny and confined by the western margin of the Kangdian uplifting faultblock, might also be at large-scale. Vertical uplifting thermodynamic field derived from mantle-sourced materials under the basin serves to facilitate migration of the basinal fluids, resulting in extension of continental crust and formation of intracontinental basins. The extension-shearing background of the continental crust may have supplied the tectonic space for localization of the basinal fluids in the study area. The paleo-buried mountains, fault-fold zones and thrusting fault-fold zones could have been the traps and tectonic sites for the basinal fluids in the area. The metallogenic series can be classified into the F-Fe-S-Sb-Au of metallogenic series controlled by the paleo-buried mountains in the superimposed-type pull-apart basin, the hot-fluid reworking Sb-As-Hg-Au series in the fault-fold zones, the Ge-Ag-Pb-Zn series in thrusting fault-fold zone of the superimposed basin and the W-Sb-Au series in the brittle-ductile shear zone.