长江中下游地区中生代构造体制转换的精细过程研究

Under the guide of plate tectonics and continental dynamics, various structural deformations, associated with Tethys and the Pacific tectonic regime transition, are aimed at. Taking the southern margin of the Dabie orogenic belt, the southern end of the Tan-Lu fault zone, the northern margin of Jiangnan Uplift belt , the middle and lower Yangtze combination structural belt and metamorphic core complex as marks, and four cross sections as key lines, then we use the geological mapping of key areas, profile drawing, structural analysis and other conventional methods, study significant tectonic events such as formation and evolution of Dabie orogenic belt, multistage strike-slip movement of Tanlu fault zone, structural overlap of Jiangnan uplift since the Mesozoic era. This project focuses on problems of formation and evolution of eastern China continent and intracontinental geological processes. Mesozoic tectonic movements and corresponding stress fields of eastern China are recognized, and stress, tectonism, sedimentary response to evolutionary process of basin and dynamic mechanics are analyzed. Tectonic events and evolution laws of basins are revealed. Fine geochronology of crust activities and tectonic events are carried out for inversion of transitions between Tethyan tectonic domain and Pacific tectonic domain. Explore some scientific problem of continental dynamics, such as formation and evolution of continent and intracontinental geological processes. Enrich content and methods of structural geology and try to make some theoretical innovations.

以板块构造学和大陆动力学的探索为指导，瞄准特提斯与太平洋两大构造体制转换有关的各种构造变形，以大别造山带南缘、郯庐断裂带南端、江南隆起北缘、中下扬子复合构造带和变质核杂岩为标志体，沿四条主要观察剖面，通过重点地区的构造地质填图、剖面绘制、构造解析等常规的构造研究方法，研究大别造山带的形成和演化过程，郯庐断裂带的多期走滑运动；江南隆起中生代以来的构造叠加等一系列重大地质事件，围绕着中国东部大陆形成、演化和陆内地质作用这一核心问题，厘定中国东部中生代构造运动和应力场，分析应力方式、构造作用、沉积响应与盆地演化时-空关系及动力学机制，揭示区内中生代构造事件、盆地演化规律，确定地壳活动和构造事件的精细年代学框架，反演特提斯构造域和太平洋构造域的发生、发展和转换过程，探索大陆形成、演化、陆内地质作用过程等大陆动力学问题，丰富构造研究的内容和方法，争取在理论上有所创新。

本项目查明了早中侏罗世中下扬子侏罗纪盆地具有北断南超、北深南浅的构造-古地理特征以及半地堑式的盆地原型；分析了大别造山带南缘襄樊-广济断裂带上缓下陡几何学特征，斜向汇聚的运动学方式和板块边缘的构造属性；细化了大别造山带南缘殷店-马垅断裂带多期右行走滑的构造性质、不同时期变形环境差异性和流变学特征；发现了桐柏-大别造山带内发育的“L构造岩”，分析了造山过程中岩石变形的构造物理环境及流变学特征；厘定了郯庐断裂带的构造属性、组合样式、演化过程，以及特提斯-太平洋两大构造体制转换的构造标志；揭示了大别造山带南缘中生代以来的叠加构造，尤其是侏罗纪末期由北向南掩盖于前陆断褶带之上的逆冲推覆构造；厘定了江南隆起带内 “表里不一”的构造变形标志，以及扬子板块北缘地壳不同层次的变形方式和构造叠加方式；解析了中下扬子地区浅表南北对冲，深部构造叠置的构造样式，研究了 “长江复合构造带”及其陆内动力学过程；研究了中下扬子地区中生代以来的构造运动、应力状态、演化过程，以及特提斯-太平洋两大构造体制转换的记录；提出了“长江中下游转换构造结概念”，分析了长江中下游中生代构造-岩浆-成矿的成因联系和时-空关系。