哀牢山变质杂岩新生代构造-热演化和剥露研究

This project focuses on the Ailao Shan metamorphic complex to study on its exhumation history and mechanism, which have important implications on understanding the shear zone formation, evolution and its regional geodynamic significance. Based on comprehensive regional geological field survey, we will have detailed study on Ailao Shan metamorphic complex, mainly including: 1)major structure components and extensive anatomy; 2)deformation- metamophic relationship of rock and mineral assemblages; 3)high- and low-temperature deformation structural and fabric analysis; 4)mineral chemical composition and deformation conditions analysis (e.g.,chlorite thermometry; Ti-in quartz thermometry; amphibole barometry; phengite barometry and so on); 5)high- and low-temperature thermochronology (U-Pb zircon dating granitic plutons; Ar/Ar geochronology on amphibole, muscovite, biotite, K-feldspar; zircon and apatite fission trackand (U-Th)/He dating). Comprehensive analysis all of deformation- metamophic relationship of rock and mineral assemblages, tectonic-thermal state and their evolution history together help to create a complete PTt-D parth, and also have comparative study to the southern Day Nui Con Voi metamorphic complex and Northern Diancang Shan metamorphic complex. All these results will reveal the exhumation mechanism of the metamorphic complex during Cenozoic and related restraining factors, as well as intensify understanding the tectonic processes of Ailao Shan-Red River strike-slip shear and further help to illuminate its role in accommodating the Indian-Eurasian plate collision and post collisional processes.

以哀牢山变质杂岩为研究对象，在系统区域构造研究基础上，深入开展哀牢山杂岩新生代构造-热演化和剥露机制的研究，主要包括：1)杂岩主要组成单元及其精细的构造解剖；2)岩石和矿物组合及变形-变质关系研究; 3)高、低温变形构造及组构分析; 4)矿物成分与变形环境计算分析(如绿泥石温度计、石英中Ti含量的TitaniQ温度计、多硅白云母压力计等); 5)高、低温热年代学分析（岩浆锆石U-Pb、角闪石/二云母/钾长石40Ar/39Ar、锆石与磷灰石裂变径迹和(U-Th)/He测年分析）。通过对杂岩精确的杂岩变形-变质关系和作用、构造-热状态及它们之间的变化规律和冷却历史地综合分析，建立一个完整的PTt-D轨迹，并与南部大象山杂岩和北部的点苍山杂岩对比研究，综合阐明变质杂岩新生代时期的剥露机制及制约因素; 深化对于红河-哀牢山走滑剪切构造过程的认识，阐释其在印度-欧亚板块碰撞和后碰撞过程中的调解作用。

新生代印度-欧亚板块碰撞与后碰撞过程是东南亚地区岩石圈结构形成与构造演化的重要事件。沿着红河-哀牢山走滑剪切带内发育的多个孤立狭长的变质杂岩体（雪龙山、点苍山、哀牢山和瑶山-大象山）记录了该构造带新生代演化历程, 但是对于该区域深变质杂岩构造-热演化及剥露未得以很好解决。该项目开展了红河-哀牢山走滑剪切带内变质杂岩及对比性地开展了阿尔卑斯爱琴海地区的野外区域地质调查与构造分析，应用多种先进实验与分析手段，重点开展了变质杂岩体内岩石、矿物变形微观构造特征(显微镜，扫描电镜及阴极发光-CL)、组构（EBSD）及变形机制的精细分析和它们的变化规律，阐释了深变质杂岩中岩石变形行为和特性及制约因素，开展了构造年度学(LAICP-MS锆石U-Pb测年)、热年度学分析（角闪石，二云母，钾长石40Ar-39Ar和磷灰石(U-Th)/He测年）、矿物成分（电子探针成分分析, 矿物对温压计算及相图）及流体作用（流体包裹体，拉曼，红外光谱）分析，限定了这些变质杂岩剥露变形构造-岩浆活动及时限，深变质岩石的深熔作用、峰期变质及多期变形-变质作用、流体活动及环境，阐明了这些变质杂岩新生代时期剥露的热-动力演化过程、剥露机制与制约因素，为正确理解变质杂岩的构造-热演化规律提供了可靠证据。项目资助的相关成果部分已经发表在如Earth-Science Reviews (2016), Geological Society of America Bulletin (2017), Tectonophyscis (2018), Journal of Asian Earth Sciences (2015, 2017), SCIENCE CHINA Earth Sciences (2018)，以及中国科学地球科学D辑等高质量刊物上。其中另外两篇被接收（地学前缘和中国科学D辑），一篇（SCIENCE CHINA Earth Sciences）修改之后将被接收，已经有两篇分别投到岩石学报，地质学报，以及Journal of Structural Geology上。参加重要的国内外大型学术会议（如EGU、CGU、青年地质大会等）交流近30次，并作相关口头学术报告。并很好地开展了国际合作交流，该项目资助数名研究生毕业论文工作，并取得了很好成绩。