西准噶尔哈拉阿拉特山地区二叠系研究

发布时间：2018-03-11 18:34

本文选题：二叠系　切入点：佳木河组　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以新疆西准噶尔哈拉阿拉特山地区二叠系沉积地层及火山岩为研究对象,通过剖面实测及路线填图,对二叠系的空间展布、岩石组合特征、基本层序、古生物化石以及相互间的接触关系等基本特征进行详细研究,取得了以下认识:1.通过对哈拉阿拉特山地区二叠系系统全面的研究,理清了研究区二叠系,自下而上依次为重新厘定的佳木河组、本次新建的白杨河组。2.佳木河组为一套典型的磨拉石建造,岩性主要有浅灰绿色、浅紫红色、灰褐色、棕色、杂色厚层状砾岩、粗砾岩、透镜状砾岩、砾岩夹含砾长石砂岩、含砾砂岩、长石岩屑粗砂岩、中厚层状砾岩夹灰绿色薄层砂岩、含巨砾中粗砾砾岩、含砾粗砂岩、长石岩屑中砂岩与杂色中细砾砾岩互层,局地见粗砂岩透镜体。下与晚石炭世阿腊德依克赛组海相细碎屑岩夹火山岩为超覆不整合,上与白杨河组陆相喷发相中基性火山熔岩、火山碎屑岩为角度不整合,与火山通道相辉绿(玢)岩株、岩脉等为侵入关系,在该组中采集到保存较完好的植物化石茎秆,细肋副芦木Paracalamites stenocostatus、鳞木Lepidodendron,结合与上下地层的接触关系,将该组时代限定在早二叠世。3.白杨河组为哈拉阿拉特山地区最晚一次火山活动的产物,至今仍保存较完整的火山机构形态,该组岩石组合齐全,火山通道相(集块岩)—喷出相(火山角砾岩、凝灰岩及少量沉凝灰岩)—溢流相(玄武岩、安山岩)—次火山岩相(辉绿岩墙),喷发不整合在佳木河组之上,并在玄武岩中获得锆石U-Pb年龄为279Ma,将其时代限定为早二叠世晚期。4.古构造环境分析,研究区在石炭系由于哈萨克斯坦板块与准噶尔洋壳的俯冲与碰撞,西准噶尔洋盆开始闭合且造山带开始形成,早二叠世由于造山带大规模的自北西向南东推覆,形成一套具前陆盆地性质的磨拉石建造,之后由于NW—SE向进一步的挤压,促使地层挤压变形形成褶皱,并在挤压松弛期玄武质岩浆喷出地表,形成现在我们看到的白杨河组陆相火山机构。
[Abstract]:In this paper, the Permian sedimentary strata and volcanic rocks in the Hara Arrate Mountain area of West Junggar, Xinjiang are taken as the research objects. The spatial distribution of Permian system, the characteristics of rock assemblages, and the basic sequence of the Permian system are studied by the measured section and route mapping. The basic characteristics of paleontological fossils and their contact relations are studied in detail, and the following understandings are obtained: 1.Through the comprehensive study of the Permian system in the Hara Arrate Mountains, the Permian system in the study area has been clarified. The order from bottom to top is the redefined Jiamihe formation, and the newly built Baiyang River formation. 2. The Jiamuhe formation is a typical morlite formation. The lithology is mainly light grayish green, light purplish red, grayish brown, brown, mixed color thick layered conglomerate, coarse conglomerate, etc. Lenticular conglomerate, conglomerate, gravelly sandstone, feldspathic coarse sandstone, medium thick layered conglomerate interbedded with grayish green sandstone, conglomerate conglomerate, conglomerate coarse sandstone, interbedded sandstone and variegated medium and fine gravelly conglomerate in feldspathic lithology. The marine fine clastic rocks of the lower and late Carboniferous Arardisai formation are supersuperimposed unconformities, the basic volcanic lava in the upper and upper continental eruptive facies of the Baiyang River formation, and the pyroclastic rocks are unconformable from the angle of the continental eruptive facies of the Baiyanhe formation. In this group, relatively well-preserved fossil plant stems, Paracalamites stenocostatus and Lepidodendron were collected from the volcanic channel facies, phenophanite (phenophane) plants, veins, etc., which combined the contact relationship with the upper and lower strata. The Baiyanghe formation is the product of the latest volcanic activity in the Hara Arrate Mountains area, and still preserves a relatively complete volcanic structure and assemblage, and its rock assemblage is complete. Volcanic passageway facies (assemblage rock / ejection facies (volcanic breccia, tuff and a small amount of sunk tuff / overflow facies) (basalt, andesite / subvolcanic facies) (diabase dike), erupting unconformity above Jiamuhe formation, A zircon U-Pb age of 279 Ma was obtained from the basalt, and its age was limited to the late early Permian. 4. Paleotectonic environment analysis. The study area in the Carboniferous is due to the subduction and collision between Kazakstan plate and Junggar oceanic crust. The western Junggar ocean basin began to close and the orogenic belt began to form. The early Permian orogenic belt, due to the large-scale northwest-south-east nappe of the orogenic belt, formed a set of mollast-bearing formations with the character of a Foreland basin, and then due to the further compression of NW-SE, During the compressional relaxation period Black Tortoise magma ejected out of the surface and formed the continental volcanic mechanism of Baiyang River formation.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P534.46

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