川滇黔接壤区MVT铅锌矿床年代学研究进展及成矿构造背景

Chronology Research Progress of the MVT Lead-Zinc Deposit in the Border Area of Sichuan-Yunnan-Guizhou and the Background of Metallogenic Tectonics

川滇黔接壤区处于扬子地块西南缘,经历过复杂的地质演化过程并分布有大量的大中型MVT铅锌矿床。对该区MVT铅锌矿床成矿年代学研究开展的大量工作成果显示该区至少经历过2次铅锌成矿事件,分别处于晚泥盆世-晚石炭世和中三叠世-早侏罗世。早期成矿事件与古特提斯洋的扩张(382~328 Ma)密切相关,在伸展构造环境下形成天宝山、大梁子、毛坪等矿床。晚期成矿事件与古特提斯洋闭合、印支期强烈挤压造山运动阶段(245~205 Ma)相对应,在挤压构造环境下形成会泽、茂租、金沙厂等矿床。不同地质背景下形成的矿床在控矿构造性质、矿体赋存规律等方面具有较大差别。在对川滇黔接壤区MVT铅锌矿床成矿时空分布规律总结的基础上,结合该区区域构造演化、矿床的控矿构造特征以及矿体赋存规律,探讨了该区不同时期控制MVT铅锌矿床形成的成矿构造环境。

The border area of Sichuan-Yunnan-Guizhou lies on the southwestern margin of the Yangtze block.It has undergone complicated geological evolution and is distributed with a large number of large and medium-sized MVT lead-zinc deposits.Previous researches were conducted on the mineralization chronology of the MVT lead-zinc deposit in the area.The result shows that the area has experienced at least two lead-zinc mineralization events,one in the Late Devonian-Late Carboniferous and the other in Middle Triassic-Early Jurassic.The early metallogenic event is closely related to the expansion of the ancient Tethys Ocean(382-328 Ma),and the extensional tectonic setting formed the deposits of Tianbaoshan,Daliangzi and Maoping.The late metallogenic event corresponds to the closure of the ancient Tethys Ocean and the strong orogenic stage of the Indosinian period(245-205 Ma).The extruded tectonic setting formed the deposits of Huize,Maozu,Jinshachang etc.The deposits formed under different geological backgrounds have great differences in the nature of ore-controlling structures and the occurrence of ore bodies.Based on the summary of the temporal and spatial distribution of MVT lead-zinc deposits in the area,together withthe regional tectonic evolution,the ore-controlling characteristics of the deposits and the occurrence of ore bodies,we discuss the ore-forming tectonic environment in different periods.