【作者】 楼达；

【导师】 李三忠；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2008， 硕士

【摘要】 黔中隆起位于贵州中西部,区内地质构造现象复杂,特别是中新生代的复杂褶皱和逆冲推覆构造是洋陆构造交接与陆内造山作用的最好演示场和天然实验室,其构造研究是突破华南大地构造研究的关键。然而长年来对处于如此重要位置的构造单元,对其构造属性等相关问题的认识尚不统一,研究程度较低。因而本文选取黔中隆起及其邻区作为解剖地区,对其复杂的多期多重多种褶皱-逆冲推覆构造进行系统的精细的构造几何学和运动学研究,并在此基础上探讨其动力学成因和演化。系统理顺了黔中隆起及其邻区复杂褶皱及逆冲推覆构造的时空关系和构造特征,得出:1.对黔中隆起及其邻区主要褶皱系统作了细致地分析,筛分出了各期次相应的褶皱及其特征:加里东运动在黔中隆起及其邻区形成了东西向宽缓的大型背向斜;海西期和印支期构造运动对黔中隆起及其邻区影响较弱,没有形成大规模的构造变形;燕山期构造运动在黔中隆起及其邻区是一次变革运动,造就了现今主要的构造形迹,其主要有3幕,形成了一系列短轴状的背向斜以及各种类型的隔槽式褶皱;燕山晚期至喜山早期主要表现为局部地段白垩系地层的南北向宽缓褶皱。2.对黔中隆起及其邻区主要的北东向弧形逆冲推覆构造和南北向弧形逆冲推覆构造等作了细致地几何学和运动学分析,得出:北东向弧形逆冲推覆构造主体于燕山晚期形成,大致与北东向褶皱同期或稍后。主要有两幕逆冲,在逆冲之后发生了伸展构造运动和一次强烈的压扭性走滑运动。该套逆冲推覆系统其推覆距离不大,基本上为一套准原地系统。南北向弧形逆冲推覆构造其构造运动的主幕与南北向隔槽式褶皱带大致同时或稍后,主幕大致在早晚白垩世之间形成,但晚白垩世之后,局部地段可能还发生过强度不大的逆冲。在主幕之后,研究区及其邻区还发生了一次伸展运动及强烈的张扭性走滑运动,影响范围较广。该南北向弧形逆冲推覆构造主推覆带大致在凯里以南、三都以北的雪峰隆起构造带突出部,其它地段推覆距离不大,基本上为一套准原地系统。3.在分析了黔中隆起及其邻区褶皱系统和断裂系统的几何学和运动学的基础上,探讨了其动力学演化模式,认为:黔中隆起及其邻区的加里东期(Z-S)构造变形与中晚奥陶世到志留纪的扬子板块与华北板块沿商丹一带近南北向的碰撞缝合有关;印支晚期-燕山早期燕山I幕(T3-J3)的构造变形其动力机制可能和扬子板块北部秦岭-大别造山带演化及印支地块的碰撞拼贴有关,且印支地块的碰撞拼贴占据主导;燕山晚期燕山II幕(J3-K1)的构造变形其动力机制与早白垩世时依佐奈琦古板块和古太平洋板块向扬子板块斜向俯冲有关;燕山晚期燕山III幕(K1-K2)的构造变形其动力机制与晚白垩世时太平洋板块变换俯冲方向和角度,由东向西向扬子板块强烈俯冲有关;燕山末期-喜山早期(K2-E)的构造变形其动力机制与喜山早期太平洋板块俯冲及印度板块碰撞有关。更多还原

【Abstract】 Qianzhong Uplift is located in the mid-west of Guizhou province, where geologic structures are complicated .In particular, Mesozoic and Cenozoic complicated folds and thrust-nappe tectonics reflect joint region between oceanic and continental tectonics and intra-continental orogeny very well. The researches on them are a key to figure out the tectonics of South China. However, the study on so important tectonic unit is relatively little, and there is not a consistent understanding on its structural attribute. Therefore, this paper focused on Qianzhong Uplift and Peripheral Regions, finely analyzed their structural geometry, kinemetics of complicated multi-stage, muti-level and multi-kind fold-thrust-nappe tectonics. We systematically discussed their dynamic genesis and development. Three conclusions have been made, as follows:1. Analyzing the main fold-systems in Qianzhong uplift and peripheral regions in detail, we separated different folds and their structure features of different geologic time: East-West wide large-scale fold formed in Caledonian movement, but there were no obvious influence of Hercynian and Indosinian movement. However, Yanshan movement which is a revolutionary movement as to Qianzhong uplift and peripheral regions, leading to the present major structures and deformed a series of short-axial fold and different kinds of though-like folds.2. The conclude is educed by a fine analysis of geometry and kinematics of the main arc thrust-nappe structure of north-east trending and north-south trending in Qianzhong uplift and its adjacent areas,that is:The NE-trending arc thrust-nappe structure is formed in the late Yanshanian, broadly with the same period of the NE-trending drape or later.A extensional tectonic movement and a strong compresso-shearing strike-Slip movement are occurred after two main thrust. The thrust-nappe system is a para autochthone for its little thrust distance. The main episode of the NS-trending arc thrust-nappe structure and its movement is formed from early to late Cretaceous, in line with the NS-trending trough-like folds’periods or later, and the local formation is possibly occurred with slight intension thrust after late Cretaceous. A extensional tectonic movement and a strong compresso-shearing strike-Slip movement happened in the research and its contiguous areas which impact on a wider scope after the main episode.The main thrust belts of the NS-trending arc thrust-nappe structure is located in the extrude part of Xuefeng uplift of Kaili south and Sandu north, while the left part is a para autochthone for its little thrust distance.3. The dynamic evolution modle of faults are discussed on the basis of geometry and kinematics analysis in the drape system and faults system of Qianzhong uplift and its adjacent areas. The tectonic-slip in Caledonian episode of Qianzhong uplift and its adjacent areas is related to the nearly NS-trending collided suture, along the vicinity of Shandan area, which is between the Huabei plate and Yangzi plate; the dynamic system of tectonic-slip from late Indosinian and the first episode of Yanshanian is possibly related to the collided convergence between the evolution of Qinlin and Dabieshan orogen of Yangzi plate and the Indosinian plate, which plays a dominant role in collided convergence; the dynamic system of tectonic-slip in the second episode of Yanshanian is related to the sidelong subduction to Yangzi plate between the early Cretaceous Izanagi plate and the Palaeo-pacific plate; the dynamic system of tectonic-slip in the third episode of Yanshanian is related to the strong intension subduction to Yangzi plate owning to the subduction direction and angles of the pacific plate of late Cretaceous were changed from East to West; the dynamic system of tectonic-slip from the late Yanshanian to early Himalayan episode is related to the subduction of pacific plate in early Himalayan episode and the collision of Indosinian plate.更多还原