湘鄂西—渝东地区构造几何学和运动学特征及其成因机制研究

发布时间：2018-03-23 10:08

本文选题：分层滑脱变形　切入点：构造几何学与运动学　出处：《中国地质大学(北京)》2015年硕士论文

【摘要】：湘鄂西—川东薄皮构造带夹持于西北侧的秦岭造山带、南东侧的雪峰山构造带以及西侧的四川盆地之间,西以华蓥山断裂为界,东以大庸断裂为界,南以涪陵—彭水—慈利一线为界。从元古代至新生代,其构造沉积演化受华南板块、华北板块演化及其陆内构造造山多期复合作用的控制,新生代以来,明显又受到青藏高原隆升的制约。鄂西—渝东地区则是二者相互作用最为强烈、构造特征最为清楚的地区。板块的碰撞拼合、陆内造山、高原隆升以及基底特征共同造成了鄂西—渝东地区不同于四川盆地其它地区的构造特征,形成了一系列隔槽式及槽挡式薄皮褶皱,反映了研究区在整体运动、隆升的过程中内部也发生着复杂而有规律的构造变化。另外,研究区自东向西发育Z→K1z地层,缺失白垩系及新生代以后的地层,这也反映了新生代以来构造环境的快速转变以及构造隆升对本区的强烈影响和改造。然而,这些构造隆升变形发生的时间,多重滑脱构造演化经历的若干阶段以及成因机制分析等,都没有得到很好的认识和解释,这也是油气勘探、华南大陆构造问题所关注的重要问题。本文以断层相关褶皱理论、构造地质学、构造年代学等为基础,综合运用最新的地质、地震(2D/3D)和钻测井资料,结合野外地质观察,做出湘鄂西—渝东地区的构造地层层序格架,并对区内地震剖面进行较为精确的刻画和精细的解释分析,包括地质结构样式、滑脱面的位置及特征等,从而进一步研究区内构造平面展布、几何学特征,结合热年代学(磷灰石裂变径迹),对区内构造隆升变形时间进行约束,并对湘鄂西—渝东地区进行运动学分析,综合以上几何学及运动学研究,加上前人研究成果,对湘鄂西—渝东薄皮褶皱带的成因机制做出合理分析。通过对湘鄂西—渝东地区构造几何学、运动学及其成因机制分析,提出有利的油气保存单元,为油气勘探部署提供地质依据和建议,并对川东、雪峰山地区的褶皱带的形成和演化提供很好的参考和成果。目前,论文主要取得了以下成果和认识:1、渝东—湘鄂西地区为分层滑脱变形,滑脱层上下变形不协调,滑脱层为基底滑脱层,下寒武统滑脱层,下志留统龙马溪组泥页岩层以及下三叠统嘉陵江组膏盐层。2、基底构造层控制着区域构造运动,各个构造层由东向西深度逐渐加深。湘鄂西地区下寒武统滑脱层为寒武系底界,川东地区下寒武统龙王庙组为主要滑脱层。下志留统龙马溪组自湘鄂西地区向川东地区由主要滑脱层转变为次要滑脱层,尤其是在方斗山以西地区更是明显。3、研究区主要发育双重构造、构造楔、断层传播褶皱以及断层转折褶皱。4、渝东地区表现为隔挡式褶皱,与滑脱层埋深浅、高粘聚力有关,湘鄂西地区发育隔槽式褶皱,与滑脱层埋深大、低粘聚力有关。5、先发育隔槽式褶皱,后发育隔挡式褶皱,构造变形由东自西逆冲。在逆冲过程中,先形成双重构造,在双重构造前方形成滑脱隔挡式褶皱。反向断层的发育可能与川中刚性基底的阻挡有关。6、研究区变形分为两个阶段,湘鄂西地区第一阶段为侏罗纪中晚期(165 Ma-145 Ma),变形发展阶段。第二阶段为古近纪中晚期(45 Ma-32 Ma),为快速隆升阶段,为湘鄂西隔槽式褶皱带变形的关键时期。渝东地区则为:一是中晚白垩世之交(135 Ma-100 Ma),构造开始隆升变形,此时主要发育滑脱褶皱,地层总缩短量为2.62 km-3.5 km,缩短率为4.89%-5.6%;二是喜马拉雅中晚期(25 Ma-15 Ma),为快速隆升变形阶段。相对而言,湘鄂西的构造隆升早于渝东地区的构造隆升,说明构造变形亦由东向西传递。
[Abstract]:The West - east Sichuan thin skinned belt clamp on the northwest side of the Qinling Mountains orogenic belt, as well as between the west side of the East Xuefengshan tectonic belt of Sichuan basin, is bounded on the west by the Huayingshan fault, to the east of Dayong fracture, South to Fuling - Pengshui - Cili line for the community. From the Proterozoic to Cenozoic. The tectonic and sedimentary evolution of the Southern China plate, control of multiple tectonic orogenic evolution of North China plate and intracontinental, since the Cenozoic, obviously by the uplift of the Tibetan Plateau of Western Hubei Eastern Chongqing area. It is the interaction between the two strongest tectonic features most clear collision plate area. The intracontinental orogenic uplift of the plateau and the basement features caused by Western Hubei Eastern Chongqing area is different from the structural features in other areas of Sichuan basin, formed a series of trough and trough retaining thin folds, which reflects the research area in the whole movement, The uplift process has also undergone a complex internal structure change regularly. In addition, the study area from east to west development, Z K1z formation, after deletion of Cretaceous and Cenozoic strata, which also reflects the Cenozoic rapid change of tectonic environment and tectonic uplift and strong impact on Transformation of this area. However, the tectonic uplift deformation time, multiple slip tectonic evolution stages and formation mechanism analysis, understanding and interpretation have not been very good, this is also the important problem of oil and gas exploration, Southern China continental concerns. Based on the theory of fault related fold, tectonic geology, tectonics based on geological chronology, the new comprehensive application (2D/3D), seismic and logging data, combined with field geological observation, make tectonic sequence stratigraphy of West Hunan Hubei Chongqing area, and in the seismic section Analysis of accurate and precise characterization of explanations, including geological structure style, slip surface location and characteristics, in order to further study the plane distribution structure in the area, geometric characteristics, combined with thermochronologic (apatite fission track), the constrained rise deformation zone between uplift, and the western Hubei Eastern Chongqing area comprehensive above research on kinematics analysis, geometry and kinematics, combined with previous research results, make a reasonable analysis of the western Hubei Eastern Chongqing thin skinned fold belt forming mechanism. Based on the structure of the West Chongqing area of geometry, kinematics analysis and formation mechanism, put forward the favorable oil and gas preservation unit, provides the geological basis and suggestions for deployment oil and gas exploration, and in the east of Sichuan, Xuefeng mountain fold belt formation and evolution provides a good reference and results. At present, the main results of this paper are as follows: 1, Chongqing - Western Hunan and Hubei layered slip deformation, slip layer deformation coordination, decollement basement detachment layer, lower Cambrian decollement, Lower Silurian shale formations and three Jialingjiang formation of gypsum salt.2, basement structure control of regional tectonic movement. Each structural layer depth deepens gradually from east to west. Areas of western part of the lower Cambrian detachment layer is the bottom boundary of Cambrian in East Sichuan area, the lower Cambrian Longwangmiao formation as the main detachment layer. The Lower Silurian from western Hubei area to the east of Sichuan by the main detachment layer into secondary decollement especially in the west area of Fangdoushan is obviously.3, it mainly develops double structure, tectonic wedge, fault propagation fold and fault bend fold.4, Chongqing area is ejective folds and detachment layer, buried depth, high cohesion, trough to the West Development Zone Fold, and decollement buried deep, low cohesion is related to.5, the first development of trough like folds, after the development of ejective folds, tectonic deformation from East West thrust. The thrust in the process of forming double structure, slip ejective folds formed in the duplex ahead. The fault was possible stop.6 and Sichuan rigid substrate, study the deformation area is divided into two stages, the first stage of the west region in the late Jurassic (165 Ma-145 Ma), the deformation development stage. The second stage is the late Paleogene (45 Ma-32 Ma), for the rapid uplift stage, a critical period for the west across slot type fold belt deformation. Chongqing area is: one is in the turn of the late Cretaceous (135 Ma-100 Ma), tectonic uplift deformation, the main development detachment fold, shorten the total formation rate was 2.62 km-3.5 km, the shortening rate is 4.89%-5.6%; two Himalaya advanced (25 Ma-15 Ma), for fast The speed of uplift deformation stage. Relatively speaking, the construction of West Hunan Hubei Chongqing area in early uplift tectonic uplift, tectonic deformation from east to west.

【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】：P542

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