滇东北-黔西北地区隆升剥蚀过程对区内铅锌矿床成矿后变化与保存的影响：锆石、磷灰石裂变径迹年代学制约

Metallogenic system contains formation and post-ore change and preservation (POCP) of deposits. Great attention has been paid to the former, not the latter in previous studies, which restricted the understanding of evolution of post-ore formation and exploration in this area. The northeast Yunnan and northwest Guizhou have excellent ore-forming conditions, which leads to forming the unusual high grade giant Pb-Zn deposits. It is mainly in northeast Yunnan that the large and super-large scale Pb-Zn deposits was found, however, the northwest Guizhou just found small and medium scale ones, and nobody knows the reason. The Pb-Zn deposits in this area have been deeply studied, which shows that they have similar metallogenic mechanism. Then, whether is it the differential denudation that lead to the giant Pb-Zn ore body in northwest Guizhou has been run out or deeply buried because of exceeding or weak erosion? This proposal intends to collect typical igneous and Paleozoic sandstone rock samples in northeast Yunnan and northwest Guizhou respectively and analyze zircon and apatite fission-track thermochronology to reveal the regional uplift and denudation process and its influence on the POCP of Pb-Zn deposits within this area. This research will be helpful in deeply understanding the distribution law of Pb-Zn deposits in northeast Yunnan and northwest Guizhou and guiding the exploration in this area.

成矿系统包含矿床的形成和成矿后的变化与保存两个方面。以往国内外的研究对前者特别关注，对后者则较少涉及，这对理解矿床形成后的演化和找矿勘查形成严重制约。滇东北-黔西北地区成矿条件优越，造就了全球罕见的高品位超大型铅锌矿床，但该区大型—超大型矿床主要发现于滇东北，黔西北则主要为矿点和中小型矿床，造成这种差异的原因目前不明。前人对该区铅锌矿床如何形成进行过深入研究，显示矿床具有相同成因。那么，是否是由于矿床形成后两地的差异性抬升、剥蚀，导致黔西北的铅锌矿体已大部分被剥蚀，或者由于剥蚀程度低而深埋地下，因而还没能在黔西北找到大型-超大型铅锌矿床？本项目拟对这两个地区典型岩体及古生代砂岩中的锆石、磷灰石的裂变径迹年代学进行对比研究，揭示两地矿床形成后的隆升剥蚀过程及其对矿床形成后变化与保存的差异性影响。本研究对把握矿床形成后的变化保存程度、深入认识研究区铅锌矿床的分布规律和指导找矿勘查具有重要意义。