东川矿区几个关键构造问题与铜矿远景评估

本文初步提出了东川大型推覆体的几何结构、烂泥坪黑矿尖子控制特高品位裂隙富矿的层控脉型脆－韧性剪切带及白锡膜矿段的构造推覆模型。根据上述研究结果著者们认为：东川地区具有发展成超大型铜矿的成矿地质条件,因而生产矿山仍有地质找矿潜力。

Some key structural problems of the Dongchuan ore district and prospective evaluation of copper deposit

Large- and medium-sized copper deposits such as Yinmin, Luoxue, Lanniping and Tangdan are in "Z"-shaped distribution in the Dongchuan copper ore district. They occur in Yinmin Formation and Luoxue Formation on the hanging wall of Dongchuan nappe. "Yinmin breccia" at the bottom of Yinmin Formation is a kind of complex tectonite formed by bedding decollement and stripping of Dongchuan nappe, rather than being volcanogene sedimentary breccia or syngenetic breccia. Based on the above viewpoint, the present paper has put forward new ideas on the copper prospects and ore-hunting targets in the Dongchuan copper district. The genesis of rich fissure ores in the Lanniping copper deposit and the structure in the Baixila deposit are also dealt with in this paper. It is held that the rich fissure ores in the Lanniping copper deposit are controlled by the interlayer brittle-ductile shear zone formed by relative movement of two bedded planes (the upper plane being the boundary between 2nd Member and 3rd Member of the late Sinian Doushantuo Formation, and the lower plane being fault surface between Doushantuo Formation and underlying Proterozoic strata), and that the predicted rich fissure ores assume equidistant en echelon arrangement relative to the known rich fissure ores, lt is also considered that in the Baixila ore deposit the eastern orebody and the western orebody are of different types and hence do not belong to one ore bed, and that the connection of the orebodies of two different beds is attributed to the dislocation of a nearly SN-trending left-lateral strike-slip fault, with the distance of the translational dislocation of the fault being some 180 m.