【作者】 王建；

【导师】 李三忠；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2010， 硕士

【摘要】 雪峰山构造系统内构造现象复杂、褶皱形态繁多、叠加方式多样,是研究褶皱叠加和陆内造山活动的天然实例。本文通过野外观察结合室内资料整理,对雪峰山地区经历的构造运动进行研究,分析各期运动的构造特点,把雪峰山构造系统划分出多个褶皱叠加类型的区块,并对典型的褶皱叠加区块进行详实的分析,建立了褶皱叠加模型,描述了褶皱叠加形成演化过程,并探讨了雪峰山构造系统陆内构造形变的动力机制。最终得出以下几点新认识和新结论：1、雪峰山构造系统变形的穿时性—递进变形。野外观察得知：加里东期角度不整合区域分布在修水-慈利-保靖-三都一线以东,即加里东构造运动影响西界为修水-慈利-保靖-三都一线；印支期角度不整合区域分布在鹤峰-来凤-三都一线以东,印支期构造运动影响西界为鹤峰-来凤-三都一线；而燕山期构造运动的影响范围西至华蓥山断裂。雪峰山构造系统由东向西,变形时间逐渐变新、变形期次逐渐减少。2、雪峰山构造系统变形的复杂多样性。纵观整个雪峰区域,存在多个方向的构造线,其中北东(NE)向、东西(EW)向、南北(SN)向为三个主体的构造线,还有北北东向(NNE)、北东东(NEE)向、北西(NW)向等次一级的构造线。产生多种构造线方向的主要原因是强构造边界对应力场的限制和改造作用。同一个地区,由于受多个边界条件的控制,可以产生多个方向的构造线。比如川东菱形构造区,在遵义-平坝断裂、彭水-正安断裂、、丰都-都匀断裂、巫山-金佛山断裂、齐岳山-习水断裂等多条边界断裂的控制下,发育了北东向、南北向、北东东向、北北东向、弧形等一系列的褶皱形态。3、雪峰山构造系统存在平列单弧、链状弧系、三角弧系、共轴叠加、斜跨叠加、限制叠加、穹盆叠加等多种褶皱叠加方式。雪峰山东侧：印支早期和加里东期褶皱共轴叠加；印支晚期褶皱受祁阳弧断裂的影响,形成联合弧的同时横跨在前两期褶皱之上叠加成典型的穹盆构造。雪峰山西侧：联合弧形褶皱比较普遍,也发育一些斜跨叠加、限制叠加。雪峰山西侧发育的最典型的叠加构造为：雁列式褶皱、菱形-弧形构造、链状弧形构造等。4、明确了雪峰山构造系统动力演化过程。晚寒武世-早奥陶世,云开地块与桂滇-北越地块由南向北运动与扬子地块拼合；奥陶世及至之后,华夏地块由南东向北西运动与扬子地块发生汇聚挤压；早-中三叠世,华南北部秦岭—大别造山带由于华北陆块和华南陆块之间的勉略洋的消亡而碰撞,形成近东西向的强大造山带,影响了扬子地块北部区域；中三叠世至晚三叠世,雪峰东侧岩石圈减薄伸展,其侧向挤压产生北西-南东向的挤压应力；中侏罗世至白垩纪初期,古太平洋板块向东亚陆缘北西向俯冲,产生北西-南东向的应力；白垩纪晚期,古太平洋板块向东亚陆缘俯冲方向发生改变,俯冲方向改向西,产生了东西向的挤压应力。更多还原

【Abstract】 There are lots of complex geological structures in the Xuefengshan tectonic system, This is one good natural laboratory to study intra-continental orogeny, especially for superposition of folds. Based on field observations and pre-existing data, This thesis carefully analyzes each tectonic events that happened in the Xuefengshan tectonic system. The Xuefengshan tectonic system in this thesis is subdivided into several areas based on different types of superposition of folds. Then this thesis selects to describe some typical superposition styles of folds for detailed structural analysis, for establishing fold superposition models and deducing a process of formation and evolution of fold superposition, and discussing characteristics of dynamics of the Xuefengshan tectonic system. Finally, four major conclusions have been made as follows.1. Progressive deformation—one major characteristic of the Xuefengshan tectonic system. Based on field observations, there is not the Caledonian unconformity at the west side of the line of Xiushui- Chili- Baojing- Sandou, it is known that the western boundary of Caledonian tectonic movement is the line of Xiushui- Chili- Baojing- Sandou. The Indosinian unconformities are strictly constrained at the east of the line of Hefeng-Laifeng-Sandou. Tthe Yanshanian unconformities, however, are controlled by the Huaying fault, just being at the east side of this fault. Therefore, it is obvious that the diachronously progressive deformation propagated from east to west.2. Structural diversity—another characteristics of the Xuefengshan tectonic system. There are different striking tectonic traces in the Xuefengshan area. NE-trending, EW-trending and SN-trending structures are majority, and NNE-trending, NEE-trending, NW-trending structures are secondary. The major reason to so many tectonic lines is the limitations and transformations of boundary faults.3. There are abundant superposition styles of folds, such as single-arc, chain-arcs, triangle-arcs, coaxial-superposition, crossing-superposition and limitation-superposition. The main structures east of the Xuefengshan are Dome-and-Basin fold superposition, while Rhomb-Arc west of the Xuefengshan.4. Dynamic evolution of the Xuefengshan tectonic system is also proposed here. In Caledonian, the Yunkai and Guidian blocks moved towards the Yangtze block from south to north, following the northwestward collision of the Cathaysian block to the Yangtze Block. Indosinian fold superposition, however, is a result of extrusion of the Qinling-Dabie Micro-continent and intracontinental collission of the Yangtze Block with the Cathaysian Block. While Yanshannian events are related to changes of subduction directions of the ancient Pacific Plate. For example, during Early Yanshannian it has a NW-directed subduction, while it has W-directed subduction in late Yanshannian.更多还原