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华北地块北缘晚古生代盆地演化及盆山耦合关系

The Evolution of Late Paleozoic Basins in North Margin of North China Block and the Coupling Relationship between Basin and Range

【作者】 周安朝

【导师】 张国伟;

【作者基本信息】 西北大学 , 构造地质学, 2000, 博士

【摘要】 华北地块北缘晚古生代聚煤盆地自西至东包括内蒙古大青山、河北兴隆、平泉、辽西南票等聚煤盆地,它们紧邻于内蒙古造山带的南侧。这些聚煤盆地中的石炭二叠含煤岩系均平行不整合于下古生界寒武奥陶系以碳酸盐岩为主的沉积地层之上。盆地的形成、沉积充填及发展演化均受控于内蒙古造山带的板块构造作用,因而是研究造山带与盆地耦合关系的良好场所,具有大陆动力学探索意义。 本次研究以板块构造理论和大陆动力学探索为学术指导思想,从活动论观点出发,以沉积作用研究为主线,重点选择具代表意义的内蒙古大青山和辽西南票两个晚古生代聚煤盆地,并把盆地的形成、沉积充填与内蒙古造山带的造山作用过程联系起来,综合分析研究,主要取得以下认识: 1.华北北缘晚古生代聚煤盆地形成于华北板块北部陆缘发生向北向西伯利亚南缘南蒙微板块之下强烈俯冲的挤压构造背景之中,并随内蒙古造山带板块构造作用的演化而盆地性质发生转化。晚石炭世-早二叠世早期华北北缘晚古生代聚煤盆地是在统一华北晚古生代克拉通盆地背景下的断坳陷盆地;早二叠世中晚期-晚二叠世由先期的断坳陷盆地转化成为前陆盆地。因而华北北缘晚古生代聚煤盆地是复合性叠合盆地。 2.华北北缘两个晚古生代聚煤盆地的砂、砾岩古流向测量、砾岩的物源分析、砂岩的骨架颗粒类型及其量比统计分析,表明陆源剥蚀区在盆地以北,且不同时期陆源区母岩组合呈规律性变化。证实石炭二叠纪时盆地北侧陆源区的风化剥蚀具有先从下古生界寒武奥陶系开始,逐渐过渡到中、新元古代沉积盖层和出现大面积的太古界变质岩及侵入其中的花岗岩为主的风化剥蚀时空演 摘 要化特点.早二叠世末-晚二叠世,内蒙古造山带先期喷发的中酸性火山熔岩也成为重要的母岩类型.陆源区的母岩组合及其变化决定于内蒙古造山带不同时期的板块构造作用。 3.华北北缘两个晚古生代聚煤盆地石炭二叠煤系地层中赋存有34-39层火山碎屑沉积事件层,可划分出12个火山事件沉积序列,且不同时期的火山碎屑沉积事件层中的主要微量元素值或比值呈规律性的变化,具有可对比性。通过与内蒙古造山带区晚石炭世、早二叠世火山岩的岩石学、岩石化学、稀土元素对比分析研究,确认华北北缘晚古生代聚煤盆地中的火山碎屑物来源于内蒙古造山带C厂P;的大规模>酸性火山喷发.盆地中的火山碎屑物是在强烈的火山爆发过程中由大气流顺并降落于盆地中、得以保存,固结成岩而成.为华北北部晚古生代聚煤盆地煤系地层的煤岩层精细对比提供了新的依据,同时也为研究盆山关系提供了证据. 个“阴山古陆”并非是古老隆升的古陆.它是在晚石炭世华北板块北部陆缘向西伯利亚板块南缘南蒙微陆块俯冲碰撞的挤压构造背景中发生拱起隆升,成为华北北缘晚古生代聚煤盆地的物源区.随造山作用的演化,在早二叠世末期-早三叠世的强烈诬撞全面造山与隆升的过程中转化成为造山带的前陆诏皱冲断带,并后又遭受中新生代构造运动的强烈叠加改造,始才成为现今古老变质结晶基底岩系广泛剥露的隆起带. 5.内蒙古造山带和华北北缘晚古生代聚煤盆地是在统一的构造框架和动力学体制下形成的孪生体,它们的形成和发展演化都受控于西伯利亚和华北两大板块构造作用,山-盆两者之间存在着耦合关系.具体表现为华北北缘晚古生代聚煤盆地伴随北侧造山带造山作用的发生和演化而形成;盆地的性质随内蒙古造山带板块作用的演化而转化;盆地的沉降、沉积充填速率及其变化、砂踞的碎屑成分变化均受控于内蒙古造山带不同时期的板块作用,同时也客观地记录和反映了内蒙古造山带的造山与隆升过程.因而内蒙古造山带和华北北缘晚古生代聚煤盆地两者之间存在着造山带与盆地在同一动力学过程中相伴共生的构造演化关系.显然,具有重要的大陆动力学探索意义.

【Abstract】 The Evolution of Late Paleozoic Basins in North Margin of North China Block and the Coupling Relationship between Basin and RangeZHOU an’chao (Dopt. of geology, Northwest University,Xi’an, 710069)AbstractThe late Paleozoic coal-gathering basins in North margin of North China Block consist of Daqingshan basin in Inner Mongolia, Xinglong basin and Pingquan basin in Hebei, Nanpiao basin in west Liaoning, etc. from west to east. The basins are closely adjacent to the south side of Inner Mongolia orogehic belt. In them, the Permo-Carboniferous coal-bearing series are parallel unconformity to the lower Paleozoic Cambrian-Ordovician sedimentary strata, which are dominated by carbonate. The formation, sedimentary insertion and evolution of basins were controlled by the plate tectonic processes of Inner Mongolia orogenic belt. Therefore, it provides us a good place for researching an orogenic belt and basin-range coupling relationship, being of great significance during studing on the continental dynamics.Based on the theories of plate tectonics and the continental dynamics as an academic advisor, the two representative basins (Daqingshan basin and Nanpiao basin) are studied. The mobilism views and the sedimentation analysis are emphasized during researching. Meanwhile, a comprehensive analysis has been used when we considered the relationship between the formation, sedimentary insertion of two basins and the processes of Inner Mongolia orogenic belt. Some conclusions are listed as follows:l.The late Paleozoic coal-gathering basins in North margin of North China Block came into the ground of compressional structure, which was affected by the strong subduction from north continental margin of North China Block to southMongolia micro-plate. With the plate tectonic evolution of Inner Mongolia erogenic belt, the attribute of the basins varied from fault and down-warped basins, which is in the ground of late Paleozoic North China craton basin in late Carboniferous, early stage of early Permian to foreland basins in middle and late of early Permian and late Permian. So the conclusion can be reached that the basins were composite overlap basins.2. The paleo-current measurement of sand and conglomerate, conglomerate source analysis, sand skeleton-grain type and the analysis of its quantity ratio obtained from the two basins indict that the terrigenous denudation lies in the northto the basin, and mother rock assemblage in land-source area is regularly variable, which has been demonstrated that the Permo-Carboniferous denudation in the north to the basins started from lower Paleozoic Cambrian-Ordovician, then the middle and late Proterozoic sedimentary cover, to mainly the vast Archaeozoic metamorphic rock and intrusion granite. In the end of early Permian and late Permian, the intermediate-acid lava erupted in The Inner Mongolia erogenic belt is also one important type of source rock. So the plate tectonic processes resulted in the different mother rock assemblage in land-source area.3.In the two basins, twelve volcanic-event sedimentary sequence could be decided by the 34-39 sedimentary event layers in Permo-Carboniferous coal-bearing series, and the selected trace element value or ratio in different layers varies regularly. Furthermore these layers could be well correlated each other. The detail lithology, petrochemistry and REE(rare earth element) analysis for the volcanic rocks shows that the volcanic clast in the late Paleozoic basins derived from volcanics in Inner Mongolia erogenic belt, which were mainly formed by the intermediate-acid materials erupted in C2- PI. The volcanic mater were transported into basin by the atmosphere current conveying and preserved very well, which provides a new proof for the precise contrast of coal-bearing series in late Paleozoic coal-gathering basins in North margin of North China Block and also provides an evidence for the study on coupling relationship between basin and range.4.1n late Carboniferous, under the ground of compressional structure formed by

  • 【网络出版投稿人】 西北大学
  • 【网络出版年期】2002年 01期
  • 【分类号】P618.11
  • 【被引频次】20
  • 【下载频次】1573
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