【作者】 蒲伟；

【导师】 曾凡桂；

【作者基本信息】 太原理工大学 ， 矿产普查与勘探， 2012， 硕士

【摘要】 聚煤盆地煤化作用对深部过程耦合和响应事件-时间序列的厘定是研究盆地有机烃源岩生烃、聚气、成油的有效途径之一，同时也是分析盆地动力学背景的关键所在。本文在广泛收集前人关于华北克拉通中部形成、演化与盆地煤变质等资料的基础上，结合野外地质调查，以沁水盆地为研究对象，建立了盆地煤化作用及其深部过程演化的事件-时间序列，并将煤化作用放入地球深部不同圈层相互作用的框架内，对沁水盆地煤变质序列与深部过程演化的耦合关系和响应机制进行了研究，主要结论如下1、沁水盆地煤化作用具时空不均一性。沁水盆地晚古生代煤至三叠纪末期，受沉积作用控制在深成变质作用下达气肥煤变质阶段，煤镜质组反射率R0等值线的平面展布继承中下三叠统沉积地层的分布特征；至中侏罗世末期，盆地南北两端近东西向的R0等值线平面分布基本成形，其时代下限为早侏罗世，盆地中部R0等值线展布方向较三叠纪末期出现异常；至早白垩世末期，盆地中部近南北向的R0等值线分布成形，其时代下限为晚侏罗世，盆地煤化作用于早白垩世末期结束，最终形成现今的煤变质格局。2、沁水盆地不同部位软流圈体系不同。扬子板块和华北板块碰撞后，于三叠纪末期自鄂尔多斯块体南部沿NNE向向山西地块北部形成一个软流圈上涌通道，并在北纬38°一线与石炭纪-二叠纪西伯利亚板块和华北板块碰撞后形成的深部流上涌带汇聚；侏罗纪-白垩纪，受太平洋板块俯沖碰撞的影响，软流圈甚至地幔流分别沿阳泉、平顺一带自东向西与三叠纪末期形成的软流圈通道相连通，深部活动达到峰值；新生代，印度-欧亚板块碰撞的远程效应使得沁水盆地北部构造体制发生转变，深部活化爆发系列火山活动。3、沁水盆地煤化作用与深部过程存在时空耦合和响应关系。将沁水盆地煤变质序列放入深部过程演化序列中发现：三叠纪，沁水盆地深部处于正常活动期；自三叠纪末期开始，深部活动受板块俯沖碰撞影响，在中侏罗世末期以前软流圈分别于沁水盆地南北两端和中部部分地区上涌，同时来自华北东部自东向西移动的深部流于盆地南北两端土涌叠加。受深部活动控制，沁水盆地南北两端晚古生代煤变质格局于中侏罗世末期已基本成形，同时中部煤变质格局出现异常；晚侏罗世-早白垩世，沁水盆地中部在再次活化的深部过程控制下煤变质格局成形，而盆地南北两端深部活动一直持续至早白垩世末期，最终沁水盆地于早白垩世末期深部活动减弱，现今煤变质格局定型。4、沁水盆地存在时空不均一的岩石圈改造/减薄。受扬子板块、太平洋板块和印度-欧亚板块的影响，沁水盆地深部软流圈整体上涌，可能在热/化学侵蚀作用下导致岩石圈减薄；岩石圈减薄的时代下限可能为三叠纪末期，于晚侏罗-早白垩世达到峰值，最早结束于晚白垩世。更多还原

【Abstract】 It was an effective way for the coalification delinking the coupling and response event-time sequences of deep processes to research the hydrocarbon generation, gas accumulation and oil formation of the coal-accumulating basin, which was also the key method to analyze the basin dynamics background. Based on the collected data about the formation, evolution and coal metamorphism of the central North China Craton, combined with the field geological survey, the event-time sequences of the coalification and deep processes of the Qinshui basin were established. After placing the coalification in the interaction framework of different spheres in deep earth, the coupling relationship and response mechanism between coal metamorphism sequence and deep process of the Qinshui basin were studied. The following results were obtained:1. The coalification showed non-uniform characteristics in space and time for Qinshui basin. The late Paleozoic coal of the Qinshui basin was controlled by the geothermal metamorphism up to gas-fat coal stage at the late Triassic, and the vitrinite reflectance (R0) isoline inherited the planar distribution of the middle-lower Triassic strata. To the end of the middle Jurassic, the nearly EW distribution of the Ro isoline in the northern and southern basin was formed, and the Ro isoline in central basin showed abnormal to the late Triassic. To the end of the early Cretaceous, the nearly NS distribution of the R0isoline in the central basin was earliest formed in the late Jurassic, when the present coal metamorphism pattern was finally completed and the coalification terminated.2. There were different asthenospheric systems in different areas of the Qinshui basin. Because of the collision between Yangtze and north China plate, a NNE asthenosphere channel from the southern Ordos block to the northern Shanxi plot upwelled during late Triassic, and at the38°N it was converged with another deep flow belt caused by the collision between Siberia and north China plate. Being influenced by the Pacific plate subduction and collision during Jurassic to Cretaceous, the asthenosphere or mantle convection was connected westwards to the asthenosphere channel shaped in late Triassic at Yangquan and Pingshun, respectively, and the deep process achieved. The volcanic activity showed a typical explosived characters in northern Qinshui basin which was related to the distant effect of the India-Eurasia collision in Cenozoic.3. Coalification showed a spatio-temporal coupling and response to the deep process. Some results from the sequence of the coalification in the deep process of Qinshui basin indicated:i. In Triassic the deep activities exhibited normally, ii. Because of the plate subduction and collision before the middle Jurassic, the asthenosphere upwelled in the northern and southern and parts of the central basin by the end of Triassic. Meanwhile, the deep flow moving westwards superimposed at the northern and southern basin. The metamorphism pattern of the late Paleozoic coal at the northern and southern basin was shaped by the control of deep activities. iii. The metamorphism pattern of the central Qinshui basin completed because of the reactivated deep process in late Jurassic to early Cretaceous, while the deep activities in the northern and southern basin continued to the end of the early Cretaceous. The present coal metamorphism pattern completed and the deep process terminated at that time.4. The modification or thinning of the lithospheric showed non-uniform characteristics in space and time for Qinshui basin. The asthenosphere deeper Qinshui basin upwelled due to the subduction and collision of the Yangtze, Pacific and India-Eurasian plate, meanwhile, the lithospheric thinning was possibly controlled by the thermal or chemical erosion. The lithospheric thinning may be started from the latest Triassic, reached peak value in late Jurassic to early Cretaceous, and early finished in the latest early Cretaceous.更多还原