保山—镇康地块及邻区早古生代地质特征及特提斯构造演化

发布时间：2017-12-26 17:45

本文关键词：保山—镇康地块及邻区早古生代地质特征及特提斯构造演化　出处：《中国地质大学(北京)》2016年博士论文　论文类型：学位论文

【摘要】：保山—镇康地块位于三江特提斯构造带西南部,夹持在潞西—三台山结合带与昌宁-孟连结合带相接之间,是研究特提斯演化关键地区。该区也是我国著名的铅锌铜金矿集区,被列入国家整装勘查区。保山—镇康地块及邻区的时空结构和演化对于中国大地构造分区、多金属找矿以及特提斯研究等具有重要的地质意义。前人对该区研究主要侧重于晚古生代古生物、沉积古地理及岩浆岩演化等方面,研究区早古生代地质记录保存相对少且后期变质变形叠加影响强烈,研究程度相对较低。本论文以保山—镇康地块及邻区为研究对象,探讨早古生代地质特征及构造演化具有重要的理论和实际意义。本论文以板块构造理论和大陆动力学思想为指导,运用盆地分析和构造解析理论和方法,将沉积-岩浆-构造-年代学紧密结合,以承担的“云南大理至瑞丽基础地质综合调查”等项目为依托,综合22幅1:5万区调新资料,系统研究了保山—镇康地块及邻区早古生代地质特征及构造演化。通过沉积地层系统研究认为保山—镇康地块早古生代为西北澳大利亚冈瓦纳被动大陆边缘盆地的一部分,新元古代末至中寒武世呈现“中间地垒两侧地堑”古地理格局;晚寒武世至早奥陶世裂谷活动发育,“堑、垒”古地理格局差异明显;中奥陶世晚期至志留纪保山-镇康地块东缘发育单斜地堑盆地,演变为“西台、东堑”构造古地理格局。新发现的蛇绿岩地球化学及同位素年代学研究认为,昌宁—孟连原特提斯大洋至少于早古生代早期已开始发育,经与龙木错—双湖结合带奥陶纪堆晶岩的对比研究,证实龙木错—双湖—怒江—昌宁—孟连是分隔泛华夏与冈瓦纳大陆的古特提斯大洋最终消亡的巨型结合带,形成时代从早古生代持续到中三叠世。研究区岩浆岩岩石学、地球化学及同位素年代学系统研究结果表明,中奥陶世昌宁-孟连洋由扩张转为向东俯冲消减,形成了早古生代中晚期西南三江陆缘弧盆系构造格局。在探讨了研究区区域构造演化基础上,提出了新元古代末至中寒武世昌宁-孟连原特提斯大洋开始扩张及冈瓦纳大陆北缘被动大陆边缘盆地发育、晚寒武世至早奥陶世昌宁-孟连洋向两侧快速扩张及冈瓦纳大陆北缘被动大陆边缘裂谷盆地发育、中奥陶世至志留纪昌宁-孟连洋向东俯冲消减形成西南三江陆缘弧盆系及冈瓦纳大陆北缘转变为被动大陆边缘盆地三个阶段构造演化模式。
[Abstract]:Sanjiang is located in the Tethys tectonic zone in the southwest of Baoshan - Zhenkang block, held in Taishan with three Luxi and Changning Menglian belt is connected between the key areas of Tethyan evolution research. This area is also a famous collection area of lead, zinc and copper gold in China and is included in the national rectification and exploration area. The space-time structure and evolution of Baoshan Zhenkang massif and its adjacent areas have important geological significance for tectono zoning, polymetallic prospecting and Tethys research in China. Previous studies focused on Late Palaeozoic paleontology, sedimentary palaeogeography and magmatic rock evolution. The early Paleozoic geological records in the study area are relatively less preserved, and the influence of late metamorphic deformation and superposition is strong, and the degree of research is relatively low. This paper takes the Baoshan Zhenkang block and its adjacent area as the research object, and discusses the important theoretical and practical significance of the geological characteristics and tectonic evolution of the early Paleozoic. In this paper, the theory of plate tectonics and continental dynamics theory, the use of basin analysis and structural analysis theory and method, combining the sedimentary magmatic tectonic chronology, taking "Yunnan Dali to Ruili based comprehensive geological survey" project, a comprehensive 22 1:5 000 regional geological data, system research the Baoshan - Zhenkang block and adjacent areas in Early Paleozoic geological characteristics and tectonic evolution. Through the study of sedimentary strata system that Baoshan - Zhenkang block to the northwest of Australia early Paleozoic Gondwana passive continental margin basin is a part of the late Neoproterozoic to Cambrian middle Horst graben shows the paleogeographic pattern on both sides "; the late Cambrian to early Ordovician rift development activities," Qian, Lei "paleogeographic pattern the difference is obvious; in the Ordovician to Silurian in Baoshan - the eastern margin of Zhenkang massif development monoclinic graben basin evolved into the western Taiwan, East graben tectonic palaeogeography pattern. The newly discovered ophiolite, geochemistry and isotope geochronology that Changning-Menglian original Tethys ocean to less than early Paleozoic era has begun to develop, with the Longmucuo Shuanghu - combined with the comparative study with the Ordovician cumulates, confirmed the Longmucuo Shuanghu - - Nu River - ning Chang Menglian is separated with the pan Cathaysian giant the palaeotethys ocean between Gondwana and the final demise of the band, formed from early Paleozoic era until three triassic. The study area magmatite petrological and geochemical and isotopic geochronology study results show that the Middle Ordovician Changning - by Meng Lianyang expansion to the eastward subduction of the early Paleozoic, late formation in southwest Sanjiang continental margin arc basin system structure. In the study area was discussed on the basis of regional tectonic evolution, the late Neoproterozoic to Cambrian Changning Meng Lianyuan Tethys ocean began to expand and the passive continental margin of the northern margin of Gondwana basin, late Cambrian to early Ordovician Changning - Meng Lianyang to the rapid expansion of both sides and the northern margin of Gondwana passive continental margin rift Middle Ordovician to Silurian Changning Meng Lianyang eastward subduction of the continental margin arc formed southwest of Sanjiang basin and the northern margin of Gondwana into a passive continental margin basin three stages of tectonic evolution pattern.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P534.4;P548

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