塔里木盆地西北缘震旦纪叠层石特征及其沉积环境意义

发布时间：2018-05-31 11:20

  本文选题：塔里木盆地 + 震旦纪　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：震旦纪,在塔里木盆地上震旦统奇格布拉克组发育有一套出露较好的叠层石,虽然对于塔里木盆地叠层石的研究前人已经有所涉及,但是绝大多数都是限于对叠层石的分布及类型做出了研究,并没有一个针对于震旦纪时期的系统的全面的叠层石的认识。本文通过大量的野外露头地质和室内薄片鉴定,分析了该区叠层石的特征、沉积环境及其演化,并利用研究叠层石,从另一种新的方法来探讨该区的沉积环境演化。该研究区位于塔里木盆地西北缘阿克苏、乌什、柯坪之间,研究区主要进行了三条剖面的研究,乌什剖面、奇格布拉克组剖面、什艾日克剖面。按照叠层石沉积环境的不同,分为四个大类,十几种不同类型的叠层石,这些叠层石包括:层状叠层石(继承体)、波状叠层石(非继承体)、丘状叠层石、具核叠层石、圆筒状朱鲁沙叠层石(相似体)、林尼尔叠层石、柱状叠层石(彭缩体)、柱状叠层石(棒状体)、柱状叠层石(规则体)、锥状叠层石、卷心菜状叠层石。本文在通过野外观察,室内分析,以及对该区震旦纪通过三个剖面的叠层石横向、纵向对比分析来得出结论。不同类型的叠层石,其成因意义也各不相同,本文利用其形态的差异来推测其沉积环境,然后进行横向、纵向的分析。纵向对比分析观察发现:乌什剖面地区附近海平面是由浅到深,再由深到浅,最后再次加深的过程;而苏盖特布拉克剖面地区附近海平面是由浅到深再快速变浅的过程;什艾日克剖面地区附近海平面是地势较高,海平面变化不大,基本保持在潮间带-潮上带过渡的过程。该区震旦纪通过三个剖面叠层石的横向对比观察分析发现:在震旦纪早期,从塔里木盆地西北缘的北侧乌什剖面,延伸至西侧的苏盖特布拉克剖面,再延伸至东侧的什艾日克剖面,海水为从西南侧向东北侧逐渐变浅的变化;在震旦纪中期,海水深度大致相同,都处在潮间带-潮上带的部位;在震旦纪晚期,海水为由北向南逐渐变浅的环境,乌什剖面处于潮下带的位置,什艾日克剖面处于潮间带-潮上带的位置。
[Abstract]:In the Sinian, there was a set of stromatolites developed in the Upper Sinian Chigebrak formation of the Tarim Basin, although the previous studies of stromatolites in the Tarim Basin have been involved. However, most of them are limited to the distribution and type of stromatolites, and there is no comprehensive understanding of stromatolites in the Sinian system. In this paper, the characteristics, sedimentary environment and evolution of stromatolites in this area are analyzed by means of a large number of outcrop geology and laboratory sheet identification, and the evolution of sedimentary environment in this area is discussed from another new method by studying stromatolites. The study area is located between Aksu, Wushi and Keping on the northwest margin of Tarim Basin. Three sections have been studied in the study area: the Wushi section, the Chigebrak formation section, and the Shiijek section. According to the different sedimentary environments of stromatolites, they can be divided into four categories. There are more than a dozen different types of stromatolites. These stromatolites include: layered stromatolites (inheriting bodies), wavy stromatolites (non-inheriting bodies), hillock stromatolites, nuclear stromatolites, Cylindrical Jurusa stromatolites (similar bodies, Linnier stromatolites, columnar stromatolites, regular bodies, tapered stromatolites, cabbage-like stromatolites. In this paper, a conclusion is drawn by field observation, laboratory analysis and comparative analysis of stromatolites from three sections of the Sinian in this area. Different types of stromatolites have different genetic significance. In this paper, the sedimentary environment of stromatolites is estimated by their morphological differences, and then analyzed horizontally and longitudinally. The longitudinal comparative analysis shows that the sea level near the Wushi section is from shallow to deep, then from deep to shallow, and finally deepens again, while the sea level near Sugetebrak section is a process from shallow to deep and rapidly becoming shallow. The sea level near the Shijic section is relatively high, and the sea level changes little, and is basically maintained in the process of transition between the intertidal zone and the upper tidal zone. The horizontal correlation analysis of stromatolites in three sections in this area shows that in the early Sinian period, from the northern Wushi section of the northwestern margin of the Tarim Basin to the west Sugait-Bulak section, The sea water is gradually shallower from the southwest to the northeast. In the middle of the Sinian, the depth of the sea water is about the same, which is located in the intertidal zone and the upper tidal zone; in the late Sinian period, the depth of the sea water is similar to that of the upper tidal zone, and in the late Sinian period, The sea water is gradually shallower from north to south, the Wushi section is located in the subtidal zone, and the Shiijk section is located in the intertidal zone and the upper tidal zone.
【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】：2017
【分类号】：P534.31
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本文编号：1959444