塔里木盆地志留系层序地层与沉积相研究

发布时间：2018-02-23 04:38

本文关键词： 层序地层沉积相志留系塔里木盆地　出处：《中国地质大学（北京）》2011年硕士论文　论文类型：学位论文

【摘要】：综合露头剖面、岩心、测井和地震资料分析,运用层序地层学和现代沉积学的理论和方法,对塔里木盆地志留系的层序地层和沉积体系进行了系统的分析。取得了以下几点成果与认识: 1、通过层序界面识别及其性质分析,结合地震关键层序界面上下的地层接触关系,依据盆地的充填演化以及古地貌格局的研究,建立塔里木盆地古生界志留系三级层序地层格架。将志留系划分为2个二级层序、4个三级层序和8个体系域,识别出3种成因界面类型。在三级层序地层格架中,分析了地层的叠加样式、转换型式与分布范围,归纳了不同沉积背景下的体系域构成特征,构建了潮坪、滨岸和三角洲层序地层模式。结合盆地构演化背景和沉积动力学过程分析,探讨了各体系域的空间展布规律及其演化特征。研究认为,基准面在上升、下降和相对稳定时期,依次发育退积型、进积型和加积型3种层序组合样式。通过对研究区的层序地层格架的对比和分析,总结了层序地层的形成和发育受控于构造沉降、湖平面变化和古气候3种要素。 2、分析了沉积相的成因类型及识别标志,识别出了塔里木盆地古生界志留系主要发育潮坪、滨岸和辫状河三角洲以及浅海陆棚等4种沉积体系。在层序格架内对不同类型沉积体系以及岩性岩相特征、相序相构成、地层叠加样式进行精细研究,归纳了层序地层格架内的沉积体系组合类型、期次关系、分布范围和空间展布特征及时空演化规律。并且探讨了不同沉积背景下层序格架内的沉积体系类型及其构成特征和空间展布关系。进一步总结了层序地层格架内各类沉积砂体的演化规律。研究表明,sq1塔中地区主要以滨岸为主,局部发育潮坪沉积,巴楚地区为潮坪沉积为主,塔北地区主要以临滨和陆棚沉积为主,塔东则以滨岸和辫状河三角洲沉积为主。sq2塔北地区属于浅海陆棚沉积,塔中-巴楚地区浅海陆棚和潮坪沉积为主。sq3以潮坪和陆棚沉积为主,仅在塔东和塔北局部发育有滨岸沉积。sq4以滨岸为主,局部发育潮坪和三角洲,其中塔北缺失此段。塔东总体以滨岸和辫状河三角洲沉积为主。总体而言,塔里木盆地志留系海侵体系域发育退积为主伴随有加积的滨岸沉积体系,高位体系域发育进积为主伴随有加积和侵蚀,发育潮坪沉积体系。 3、通过对塔里木盆地北部地区锆石测年的研究,推测塔北中东部地区的物源主要来自阿尔金地区奥陶纪火成岩,塔北西部地区的物源主要来自塔北前寒武纪基地。
[Abstract]:Synthesizing outcrop profile, core, logging and seismic data analysis, applying theories and methods of sequence stratigraphy and modern sedimentology, The sequence stratigraphy and sedimentary system of Silurian in Tarim Basin are systematically analyzed. 1. Through the identification of sequence interface and the analysis of its properties, combined with the stratigraphic contact relation between the upper and lower key sequence interfaces of the earthquake, according to the filling evolution of the basin and the study of the paleogeomorphological pattern, The third-order sequence stratigraphic framework of Silurian in the Paleozoic of Tarim Basin was established. The Silurian was divided into two secondary sequences, four third-order sequences and eight system tracts, and three genetic interface types were identified. The superposition style, transformation type and distribution range of the strata are analyzed, and the system tracts under different sedimentary background are summarized, and the tidal flat is constructed. Seashore and delta sequence stratigraphic models. Based on the analysis of the tectonic evolution background and sedimentary dynamics of the basin, the spatial distribution and evolution characteristics of each system tract are discussed. It is considered that the base-level is rising, decreasing and relatively stable. Three types of sequence combination patterns are developed in turn: regressive type, precession type and accretion type. Based on the correlation and analysis of sequence stratigraphic framework in the study area, it is concluded that the formation and development of sequence stratigraphy are controlled by tectonic subsidence. Changes of lake level and paleoclimate. 2. The genetic types and identification criteria of sedimentary facies are analyzed, and the main tidal flat developed in Silurian of Paleozoic in Tarim Basin is identified. Four kinds of sedimentary systems, such as shoreline, braided river delta and shallow sea shelf, are studied in detail on different types of sedimentary systems, lithologic lithofacies, facies sequence facies composition and stratigraphic superposition style in sequence framework. The types of sedimentary system assemblages in sequence stratigraphic framework are summarized. The distribution range, spatial distribution characteristics and space-time evolution law are discussed. The types of sedimentary systems in the lower sequence framework of different sedimentary backgrounds, their composition characteristics and spatial distribution relations are discussed. The sequence stratigraphic framework is further summarized. The evolution of various types of sedimentary sand bodies. The tidal flat deposits are mainly developed in Bachu area, the littoral and shelf sediments are dominant in Tarim area, and the shoreline and braided river deltaic sediments are dominant in the east of Tarim Basin. In the Tazhong-Bachu area, the shallow sea shelf and tidal flat sediments are mainly. Sq3 is mainly tidal flat and shelf sedimentary, only in the east of Tarim and north of Tarim, there are mainly shoreline sediments .sq4, the tidal flat and delta are developed locally, and the tidal flat and deltas are mainly developed in Tazhong-Bachu area. In general, the Silurian transgressive system tract in the Tarim Basin is characterized by retrogression and accretion of the shoreline sedimentary system. The high level system tract is characterized by accumulation and erosion, and tidal flat sedimentary system. 3. Based on the study of zircon dating in the northern part of Tarim Basin, it is inferred that the provenance in the central and eastern part of Tarim is mainly from the Ordovician igneous rocks in Altun area, and that in the western part of Tarim Basin the provenance mainly comes from the Precambrian base in the north of Tarim Basin.
【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】：2011
【分类号】：P618.13

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