准噶尔盆地南缘和东缘地区侏罗系沉积特征及构造背景

发布时间：2018-04-16 22:35

本文选题：准噶尔盆地 + 侏罗纪　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：准噶尔盆地南缘和东缘侏罗系发育良好,沉积特征明显,是研究侏罗系沉积环境和构造背景的理想地层。通过对准噶尔盆地南缘和东缘侏罗系共5条剖面的地层沉积特征进行研究,确定了侏罗系的岩石类型和沉积相类型,总结了各种沉积相和微相的特征,分析了沉积物源区,并对准噶尔盆地东缘的构造-沉积演化过程进行重塑。研究区岩石类型主要有砾岩、砂岩、粉砂岩、泥岩和泥质灰岩。研究区沉积相类型主要为辫状河流相、辫状河三角洲相、曲流河三角洲相和湖泊相。在沉积物源区方面,准噶尔盆地南缘侏罗系的物源来自于天山造山带的支脉博格达山;准噶尔盆地的东北缘侏罗系的物源来自于克拉美丽造山带。在构造-沉积演化方面,受博格达山和克拉美丽山隆升作用的影响,在侏罗系的不同时期,盆地东部的南、北两侧显示出不同的沉积相组合。早侏罗世,准噶尔盆地南侧的博格达山脉和东北侧的克拉美丽山均快速隆升,准噶尔盆地南缘和东北缘的沉积相均为辫状河三角洲沉积相,盆地内部则发育半深湖-深湖相。在此期间,准噶尔盆地经历了几次规模较大的湖侵,盆地内大部分地区被湖泊淹没,煤层不发育,物源供给较少。中侏罗世早期,准噶尔盆地南侧的博格达山脉和北侧的克拉美丽山脉的隆升速度均较低,准噶尔盆地南北都形成了曲流河三角洲沉积相。中侏罗世后期-晚侏罗世,准噶尔盆地南侧的博格达山脉隆起较快,发育了头屯河组-喀拉扎组的辫状河-辫状河三角洲沉积相;盆地东北部的克拉美丽山隆升速度较缓,发育了曲流河三角洲的石树沟群的沉积。此期间,两侧山脉的隆升导致湖平面下降,水体深度变浅,盆地内部由半深湖相变为浅湖相。此时气候温暖湿润,植物生长最为繁盛,盆地内形成了大面积的沼泽环境,煤层发育达到极盛时期。
[Abstract]:Jurassic in the southern and eastern margin of Junggar Basin is well developed and has obvious sedimentary characteristics. It is an ideal stratum for studying the sedimentary environment and tectonic setting of Jurassic.Based on the study of sedimentary characteristics of five Jurassic sections in the southern and eastern margin of Junggar Basin, the types of Jurassic rocks and sedimentary facies are determined, the characteristics of various sedimentary facies and microfacies are summarized, and the source areas of sediments are analyzed.The tectonic-sedimentary evolution process in the eastern margin of Junggar Basin was remolded.The main rock types in the study area are conglomerate, sandstone, siltstone, mudstone and argillaceous limestone.The sedimentary facies in the study area are mainly braided fluvial facies, braided river delta facies, meandering river delta facies and lacustrine facies.In terms of sediment source, the source of Jurassic in the southern margin of Junggar Basin comes from the Bogda Mountains, a branch of the Tianshan orogenic belt, and the material source of Jurassic in the northeast margin of Junggar Basin comes from the Kramer orogenic belt.In terms of tectonic-sedimentary evolution, due to the uplift of the Bogda Mountains and the Clarisian Mountains, there are different sedimentary facies assemblages on the south and north sides of the eastern part of the basin at different stages of the Jurassic system.In the early Jurassic, the Bogda Mountains in the southern side of Junggar Basin and the Kelieshan Mountains in the northeast side of the Junggar Basin rose rapidly. The sedimentary facies of the southern margin and the northeast margin of the Junggar Basin were both braided river delta sedimentary facies, while the half-deep lacustry-deep lacustrine facies were developed in the interior of the basin.During this period, Junggar Basin experienced several large-scale lake transgressions. Most areas of the basin were submerged by lakes, the coal seams were not developed, and the material supply was less.In the early Middle Jurassic, the uplift rate of the Bogda Mountains in the south of Junggar Basin and the Clemish Mountains in the north side of the Junggar Basin were lower, and the meandering river delta sedimentary facies were formed in the north and south of Junggar Basin.From the late Middle Jurassic to the late Jurassic, the Bogda mountain uplift in the southern side of Junggar basin was relatively rapid, and the braided river braided river delta sedimentary facies of Toutunhe formation and Kalazar formation were developed, while the uplift rate of Kramieshan in the northeastern part of the basin was relatively slow.The deposits of the Shishugou Group in the meandering River Delta have been developed.During this period, the uplift of the mountains on both sides of the basin caused the lake level to decrease, the depth of the water body shallower, and the interior of the basin changed from semi-deep lacustrine to shallow lacustrine.At this time, the climate is warm and humid, plant growth is the most prosperous, a large area of swamp environment has been formed in the basin, and the coal seam has reached the peak stage.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.11;P534.52

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