会泽型(HZT)富锗银铅锌矿床成矿构造动力学研究及年代学约束

Metallogenic Tectonic Dynamics and Chronology Constrains on the Huize-type(HZT) Germanium-rich Silver-Zinc-Lead Deposits

川-滇-黔多金属成矿域是会泽型（HZT）富锗银铅锌矿床的主要分布区。近十年来，该类矿床成矿时代及其成矿构造动力学一直是该区研究的主要热点之一。针对铅锌矿床准确定年的难题，首次综合应用地质推断-构造变形筛分-构造古应力系统测量-同位素定年技术，提出冲断褶皱构造形成时代与矿床成矿时代一致，其主体时代为印支晚期（2.0~2.3亿年）。研究认为，该期发生的铅锌多金属成矿作用是川-滇-黔接壤区重要的地质事件，其成矿构造动力学为印支晚期特提斯洋闭合与造山作用在扬子地块西南缘前陆盆地诱发强烈的斜冲走滑，形成一系列冲断褶皱构造带，并发生流体大规模运移，在有利的构造部位形成一批大型-超大型矿床。该认识对深化川-滇-黔多金属成矿域铅锌矿床成矿模型、优选找矿标志、圈定重点找矿靶区和实现找矿突破具有现实意义。

TheHuize-type （HZT） Ge-rich Ag-Zn-Pb deposits are located in the famous Sichuan-Yunnan-Guizhou zinc-lead poly-metallic mineralization domain （SYGD）. The metallogenic epoch and tectonic dynamics background for the HZT Zn-Pb deposits havebeenintensively researched and actively debated in the last decade. Based on systematic geological investigation, analysis of the ancient structural stress, and isotopic geochronology study, we propose that the major ore-forming epoch is the late Indosinian （230–200 Ma） which is coincident with the main formation epoch of thrust-folding in SYDG. The late Indosinian Zn-Pb polymetallic mineralization is very important in SYGD, which has not yet been widely recognized. We suggest that the formation of the late Indosinian ore deposits was resulted from massive migration of basin flow associating with the thrust-fold structures in the foreland basin on the southwestern margin of the Yangtze Block related to the closing of the Tethys Ocean and oblique slips during the orogenic processes.