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1.
"从源到汇"理论完善了砂箱物理模型中地壳浅表构造-剥蚀-沉积耦合过程机制的理解,我国西部地区新生代发生了全球最为显著的构造-剥蚀-沉积作用过程,却少见相关浅表作用过程报道。本文系统阐述地壳浅表作用过程机理和挤压砂箱模型"从源到汇"过程的相似性机理,基于国内外以冲断带-前陆盆地系统相关浅表作用过程(即构造-剥蚀-沉积)为对象的砂箱物理模型研究结果,综述浅表构造-剥蚀-沉积耦合过程及其对褶皱冲断带系统形成演化的主要控制因素。"从源到汇"的浅表作用过程有利于褶皱冲断带-前陆盆地系统物质与能量的交换与互馈,剥蚀作用主要作用于褶皱冲断带后缘区域,有利于形成较窄的冲断带-前陆盆地体系;沉积作用不仅受控于造山带或褶皱冲断带源区剥蚀作用过程,还受控于沉积物路径过程等复杂因素,其主要作用于褶皱冲断带前缘与前陆盆地区域,较高的沉积物沉积作用有利于形成较宽的冲断带-前陆盆地体系。临界楔理论强调挤压增生楔形体前缘加积物质(输入)与楔形体表面剥蚀物质(输出)达到平衡后楔形体呈自相似性生长,即造山楔形体地表坡度与基底坡角之和趋于恒定,它们共同控制其褶皱冲断带-前陆盆地系统构造-剥蚀-沉积浅表作用过程及其时空范围。构造砂箱物理模型与褶皱冲断带系统"从源到汇"浅表剥蚀-搬运-沉积作用过程的标准变量/参数的一致性对比研究,是当前二者相结合的重点与难点之一,毫无疑问的是,对于"从源到汇"浅表作用过程天然实验室中典型褶皱冲断带/流域体系的构造砂箱物理模型模拟研究,将会持续不断地拓展和完善其理论体系格架与内容。  相似文献   

2.
基于多封闭系统低温热年代学特征的浅部地貌构造模型重建在揭示褶皱冲断带-前陆盆地系统形成演化过程中受到越来越广泛的重视与应用。青藏高原东缘龙门山地区多封闭系统低温年代学年龄总体上具有逐渐从冲断带前缘、由SE向NW至高原内部减小趋势,且走向上由NE向SW也具微弱减小趋势;龙门山褶皱冲断带热年代学年龄变化范围明显大于高原内部,揭示出盆-山过渡带新生代加强的褶皱冲断剥蚀浅表作用。基于龙门山区域低温热年代学和褶皱冲断带-前陆盆地系统稳态冲断剥蚀热模型,揭示出青藏高原东向扩展速率约为5~10 mm/a,抬升剥蚀速率为0.4~1.0 mm/a和龙门山褶皱冲断带缩短速率为0~15 mm/a,它们与现今地质学和大地测量学特征具有较好的一致性。因此,青藏高原东缘由西向东的多封闭系统热年代学年龄特征反映出新生代稳态的高原东向扩展生长过程,即龙门山褶皱冲断带冲断扩展和浅表剥蚀作用耦合过程。  相似文献   

3.
龙门山前陆褶皱冲断带构造解析与川西前陆盆地的发育   总被引:57,自引:2,他引:55  
通过详细的野外地质调查和精细的地震剖面构造解析。揭示了龙门山前陆褶皱冲断带的基本构造特征。对比分析了龙门山北段与南段构造变形几何学和运动学的差异。提出龙门山北段主要表现为一系列复杂的逆冲推覆构造,晚三叠纪变形强于新生代;龙门山南段则以基底卷入的叠瓦状冲断为特点,晚白垩纪-早第三纪变形尤为突出。与前陆褶皱冲断带相对应的是,川西晚三叠纪时期的周缘前陆盆地主要表现在整个龙门山褶皱冲断带的前渊地区;而晚白垩纪-早第三纪再生前陆盆地却局限在川西盆地的南部,并且印-藏碰撞的持续挤压作用使得晚新生代构造变形不断向东扩展进入川西盆地南部。  相似文献   

4.
中国西天山南缘盆山构造转换解析   总被引:15,自引:4,他引:11  
李向东  王克卓 《新疆地质》2000,18(3):211-219
在西天山南缘,天山造山带向塔里木盆地北缘的盆山过渡,是以前陆褶皱冲断构造形式向库车一拜城前陆盆地渐变,表现为一系列褶皱冲断组合的构造样式。根据独库公路南段构造变形分析,可组合成6个部分:库尔干一铁力买提达坂根带褶皱系、南天山南缘逆冲断裂带、前陆逆冲推覆构造带、前陆双冲褶皱构造带、前陆隐伏逆冲前缘构造带、沙雅一轮台前缘叠加变形构造带。前陆盆地的发展可以划分为晚二叠一早三叠世、中三叠世一侏罗纪、白垩一  相似文献   

5.
奥雷褶皱冲断带是巴布亚新几内亚油气勘探的重要区域,但对褶皱冲断带的构造变形样式与演化认识不清。利用覆盖全区的2D和3D地震资料、钻井和地质信息,结合前人在该地区的地质研究成果,以断层相关褶皱理论为指导,对地震资料进行了闭合解释,系统分析了该区褶皱冲断带的构造几何学与运动学特征。研究结果表明:奥雷褶皱冲断带沿走向可以分为东段、中段和西段3段,其构造变形具有明显的差异性:(1)沿倾向从NE向SW具有变形层次渐浅、卷入层系渐新、变形程度渐弱的变化特征;(2)沿走向从NW向SE表现为扩展范围渐小、前陆沉积层系渐新、构造变形时间渐晚、缩短率渐大、缩短量渐小的特征;(3)西段和中段垂向上分层解体,东段为继承性变形。本次研究将助力巴布亚新几内亚的油气勘探,并为澳大利亚北缘区域构造演化研究提供盆内证据。  相似文献   

6.
塔西南新生代前陆盆地东段盆山结构与冲断带变形特征   总被引:1,自引:0,他引:1  
塔西南新生代前陆盆地受西昆仑山造山带南北向挤压和帕米尔弧形构造带向北突进的影响,导致盆山结构与盆地冲断带构造变形在平行造山带方向表现出明显差异。本文通过地震资料解释,系统研究了塔西南新生代前陆盆地东段盆山结构与冲断带的构造变形特征,认为塔西南新生代前陆盆地东段盆山结构表现为西昆仑造山带向北大规模冲断,盆地区挠曲沉降,前陆地区发育宽的褶皱冲断带,冲断带前锋已扩展至捷得背斜一线,褶皱冲断带与前渊坳陷存在大范围重叠。盆地东段的褶皱冲断带在纵向上可以分为基底卷入变形带、滑脱变形带。山前第一排变形带受多期构造叠加影响,产生横向变形的分异:西段柯东段早期为构造楔形体变形形成的背斜构造,后期被甫沙–克里阳右行走滑断裂改造,剖面呈现复杂的变形特征;东段克里阳段构造变形以早期的逆冲推覆为主。结合生长地层与磁性地层分析,冲断带的变形总体表现出前展式的构造变形特征,上新世阿图什组沉积期开始形成柯东构造带;随后变形向北传播,在上新世早中期形成柯克亚构造带;至早中更新世晚期,构造变形扩展至固满–合什塔格构造带。  相似文献   

7.
上扬子地区褶皱-冲断带的运动学特征   总被引:6,自引:0,他引:6       下载免费PDF全文
上扬子地区褶皱-冲断带的运动学特征一直缺乏系统研究。在前人基础上,结合野外认识、地震地质剖面解释、构造活动定年等相关成果分析认为,上扬子地区印支期以来至少存在着3组不同方向的区域挤压应力。其中,NW-SE向挤压应力具印支期、燕山期与喜马拉雅期多期活动特点,近SN向挤压应力主要在燕山晚期,NE-SW向挤压作用主要发生在喜马拉雅期。由此所形成的造山带至前陆褶皱-冲断带的运动学结构模式存在较大差异,即龙门山造山带发育了较为典型的根带、中带、锋带与外缘带等复杂的逆冲推覆构造系统,米仓山与南大巴山造山带缺乏中带变形的特征,雪峰山陆内前陆盆地系统则表现为逆冲的锋带在倾向上传播距离长、在走向上影响范围大等特点。上扬子地区褶皱-冲断带的运动学特征控制了不同时期油气的运移方向及聚集场所。  相似文献   

8.
西准噶尔吾尔喀什尔山与额敏盆地间的"盆"–"山"耦合关系清楚,盆地边界平行于造山带呈狭长带状展布。"山"区为志留系–石炭系海相陆源碎屑岩-火山岩沉积组合,"盆"区为二叠系陆相磨拉石与新近系红色砂砾岩及第四系河流阶地堆积,具有典型的海相-陆相双层结构。盆缘被巴尔雷克前陆冲断带围限,"山"区发育铲式逆冲断层与蛇头构造、叠瓦扇构造等逆冲推覆构造。表明该"盆"–"山"组合为一典型的前陆盆地系统。额敏前陆盆地形成于早二叠世,属后期冲断变形影响较弱、早期前陆盆地结构特征较明显的"早衰型"前陆盆地。这一成果为额敏盆地乃至西准噶尔盆地分析、构造演化、沉积作用、"盆"–"山"耦合等研究提供了重要信息。  相似文献   

9.
《地学前缘》2017,(3):127-136
前陆盆地油气资源丰富但构造变形十分复杂,使得前陆盆地构造-热演化模拟面临挑战。前陆盆地演化过程中构造与热的耦合体现在多个层面:岩石圈热演化对岩石圈强度时空分布及其挠曲的影响;逆冲推覆作用的浅部温度效应;快速沉积作用对盆地温度场的影响等。首先,前陆盆地形成时的岩石圈热背景及其造成的岩石圈强度空间变化对盆地后期的演化具有重要影响。同时早期热事件的热扰动也会叠加在前陆盆地的构造-热演化过程中,并不断衰减,影响岩石圈的流变结构,从而带来一系列的影响。热与构造演化相耦合在前陆盆地定量模拟中非常重要。其次,还需特别关注岩石圈深部过程与近地表构造过程的耦合。造山带逆冲推覆、抬升和剥蚀是与前陆盆地形成相关的重要构造活动,这种运动引起的热对流对造山带的热结构、前陆逆冲带以及前渊地区的温度场的分布有着重要影响。最后,前陆盆地形成演化过程中的快速沉积作用对盆地温度场和地表热流产生强烈的压制作用,对前陆盆地浅部热演化的影响不容忽视。因此,在浅部热演化(包括造山带逆冲推覆、快速沉积压实等)与盆地下伏岩石圈挠曲、深部热演化的联合作用下,使得前陆盆地构造-热演化颇为复杂,二者的耦合使得前陆盆地构造-热演化模拟颇具挑战。  相似文献   

10.
早中生代(晚印支-早燕山期)岳阳-赤壁断褶带位于江南造山带与中扬子前陆盆地交界地带.作者对该构造带进行了地表地质调查,以此为基础探讨了构造剖面结构及构造变形动力机制.岳阳-赤壁断褶带自南而北可分为岳阳-临湘基底滑脱-逆冲带,桃花泉-肖家湾盖层滑脱褶皱带,以及赤壁-嘉鱼前陆盆地断-褶-盆构造带.岳阳-临湘基底滑脱-逆冲带自南而北依次有郭镇向斜、官山背斜、临湘倒转向斜和聂市背斜,组成隔槽式褶皱组合.褶皱轴面多向南倾,褶皱变形面为南华系盖层与冷家溪群褶皱基底间的角度不整合面和顺界面的滑脱断裂面.桃花泉-肖家湾盖层滑脱褶皱带主要发育轴面南倾倒转褶皱,褶皱波长较小,卷入地层为南华系-志留系以及上石炭统-中三叠统沉积盖层.赤壁-嘉鱼前陆盆地断-褶-盆构造带以南倾蒲圻断裂(江南断裂)为南部边界,发育T3-J2前陆盆地沉积,带内褶皱与断裂卷入地层包括沉积盖层以及T3-J2地层:南部断裂与褶皱轴面南倾.北部轴面近直立.自南西至北东,研究区内构造线走向由EW向渐变为NEE-NE向.上述构造分带及变形特征反映出自南向北的运动指向,表明岳阳-赤壁断褶带具前陆冲断带构造性质.从断裂相关褶皱理论出发,以地表构造特征为依据,厘定了岳阳-赤壁地质剖面结构并进行了变形动力机制分析,认识如下:①自南而北、自下而上的多个滑脱层及其间的南倾逆断裂或断坡(主要为江南断裂)组成近似台阶状的逆冲断裂系统,从总体上控制了构造块体的滑移、逆冲以及相应的构造格架或变形分区.②郭镇向斜为基底滑脱褶皱,官山背斜具滑脱褶皱和断裂传播褶皱双重成因,聂市背斜为断裂转折褶皱;临湘向斜为受两侧背斜控制的被动向斜,由于弯滑褶皱作用在其两翼沿不整合界面形成滑脱断裂.③岳阳-临湘基底滑脱-逆冲带隔槽式褶皱的形成主要受控于褶皱基底的滑脱和基底整体的水平压缩,其形成机制类似于肿缩式褶皱.最后讨论认为湘东北-鄂东南地区不存在大规模、长距离的逆冲推覆构造.  相似文献   

11.
Comparison between numerical models and structural data is used for a better understanding of the evolution of the Siwalik thrust belt of western Nepal. The numerical model involves discontinuities within a critical wedge model, a kinematic forward model of serial cross sections, and a linear diffusion algorithm to simulate erosion and sedimentation. In western Nepal, large Piggy-back basins (Duns) are located above thick thrust sheets that involve more than 5500 m of the Neogene Siwalik Group, whereas Piggy-back basin sedimentation is less developed above thinner thrust sheets (4300 m thick). Numerical model results suggest that thrust sheet thickness and extension of wedge-top basins are both related to an increase of the basal décollement dip beneath the duns. The West Dang Transfer zone (WDTZ) is a N–NE trending tectonic lineament that limits the westward extent of the large Piggy-back basins of mid-western Nepal and is linked to a thickening of the Himalayan wedge eastward. The WDTZ also affects the seismotectonics pattern, the geometry of the thrust front, the lateral extent of Lesser Himalayan thrust sheets, and the subsidence of the foreland basin during middle Siwalik sedimentation. Numerical models suggest that the individualisation of the Piggy-back basins at the transition between the middle Siwalik and upper Siwaliks followed the deposition of the middle Siwaliks that induced a geometry of the foreland basin close to the critical taper. As WDTZ induces an E–W thickning of the Himalayan wedge, it could also induce a northward shift of the leading edge of the ductile deformation above the basal detachment in Greater Himalayas of far-western Nepal. Field data locally suggest episodic out-off-sequence thrusting in the frontal thrust belt of western Nepal, whereas numerical results suggests that episodic out-off sequence reactivation could be a general characteristic of the Himalayan wedge evolution often hidden by erosion.  相似文献   

12.
关于汶川地震发震机制   总被引:10,自引:0,他引:10  
2008年5月12日汶川8级地震的发震断层是四川龙门山逆冲带的前锋灌县—安县断层,或此断层附近新产生相同产状的断层。发震断层走向NE倾向NW,逆冲兼右行平移。汶川地震的发震机制是印藏陆-陆碰撞后,印度次大陆活塞状嵌入欧亚板块造成青藏高原东部向SEE方向近水平挤压,在龙门山冲断带前锋向东南逆冲到四川盆地,构造应力积累和释放的结果。汶川地震演示了一个青藏高原东缘龙门山隆起的构造模型,即其经由龙门山冲断带的地壳冲断作用和缩短作用而隆升。这与Burchfiel的模型不同,该模型认为龙门山上升是由于韧性下地壳流受到四川盆地高强度地壳阻挡而上涌所致。这两种模型可能各有其适用时间阶段,然而本文的模型是不可或缺的,因汶川地震已显示了它的真实性。  相似文献   

13.
试论龙门山逆冲推覆作用的沉积响应─—以成都盆地为例   总被引:3,自引:0,他引:3  
本文根据现今龙门山前陆盆地(成都盆地)沉积特征和龙门山冲断带第四纪以来的逆冲推覆事件,研究了龙门山逆冲推覆作用对成都盆地沉积的控制作用和成都盆地沉积对龙门山逆冲推覆作用的响应,总结了龙门山冲断带逆冲推覆作用的沉积响应模式和地层标识,为研究龙门山冲断带地质演化提供了新的思路和方法。  相似文献   

14.
We demonstrate that increasing erosion during the kinematic evolution of a thrust wedge will lead to out‐of‐sequence thrusting as a result of backwards critical taper movement. In‐sequence thrusting in the Subalpine German Molasse Basin built a critical‐tapered foreland Coulomb thrust wedge. Later, out‐of‐sequence thrusts dissected all but the frontal duplex stacks. The footwall/hangingwall relation visible on seismic data proves the out‐of‐sequence nature of the latest thrusting stage. Establishing a stable drainage system leads to increased erosion in elevated areas of the thrust wedge, resulting in flattening of the critical wedge. In order to keep its predefined angle, the critical wedge repositions and the tip of the taper moves towards the hinterland. Thus, thrusting will also reposition and move towards the hinterland.  相似文献   

15.
库车坳陷东、西段盐下构造在北部构造带以南出现明显的差异构造变形特征,在西段的克拉苏构造带盐下发育由一系列逆冲断裂组成的叠瓦构造,而在东段的东秋构造带盐下发育一个大型的断背斜构造。本文基于地震资料构造解析,采用离散元数值模拟方法,设计了5组数值模拟实验来探究先存断层、同构造沉积和滑脱层强度对褶皱冲断带构造形态及演化的影响,进而分析库车坳陷东、西段构造特征差异的成因机制。模拟结果表明含盐褶皱冲断带往往发育垂向分层构造变形。先存断裂会影响褶皱冲断带构造传播的方式,导致盐下楔体形态、断裂数量和盐上构造样式的差异。同构造沉积会增强盐上和盐下的分层差异变形,滑脱层强度增强会减弱盐上和盐下的分层变形。通过将模拟结果与库车坳陷东、西段构造特征进行对比分析,我们认为先存断层可能是影响库车坳陷东、西段盐下构造差异演化的重要因素。库车坳陷东段的东秋构造带受先存断裂影响,在先存断裂的位置优先变形,形成东秋断裂和上覆东秋背斜,同时先存断裂既有助于应力释放,又阻拦应力向前传递,形成乱序式变形传播。库车坳陷西段的克拉苏构造带,没有先存断裂的影响,盐下主要发育前展式构造变形,形成由一系列逆冲断层组成的叠瓦构造楔体。  相似文献   

16.
A foreland basin succession has been identified in the Frasnian of the Central Pyrenees. This succession comprises a carbonate-dominated transgressive system which recorded the cratonward migration of the foreland basin subsidence, and siliciclastic depocenters which recorded the progression of the thrust-fold deformation. The foreland basin system has always been maintained in deep-marine environments, i.e., at an underfilled depositional state. It was associated with a thrust wedge which descended toward a deep-marine hinterland, i.e., with a type of orogenic wedge usually related to subduction zones. The Frasnian foreland basin system differs from the one known in the Carboniferous which evolved to overfilled depositional state and was associated with a thrust wedge rising toward a mountainous hinterland. Consequently, the Hercynian orogeny in the Pyrenees seems to result first, from a Frasnian thrusting controlled by a subduction zone located north of the Pyrenees, and second, from a Carboniferous thrusting controlled by the surrection of a frontal thrust belt in the Pyrenees. The association of underfilled foreland basin systems and hinterland-dipping thrust wedges, as exemplified in the Frasnian of the Pyrenees, can be interpreted as illustrative of the initial stages of thrust-wedge growth in deep-marine settings.  相似文献   

17.
Cenozoic sedimentary deposits in central-southern Ningxia province, NW China are an important record of Tertiary tectonic events along the evolving Qinghai–Tibetan Plateau’s northeast margin. Shortly after the onset of the Indo-Eurasia collision to the south, a thrust belt and adjoining foreland basin began to form during 40–30 Ma. The Eocene Sikouzi Formation developed in a distal setting to this basin, in normal fault-bound basins that may have formed in a forebulge setting. Subsequent deposition of the Oligocene Qingshuiying Formation occurred during a phase of apparently less intense tectonism and the previous underfilled foreland basin became overfilled. During the Early Miocene, contractional deformation was mainly distributed to the west of the Liupan Shan. This resulted in deformation of the Qingshuiying Formation as indicated by an unconformity with the overlying Miocene Hongliugou Formation. The unconformity occurs proximal to the Haiyuan Fault suggesting that the Haiyuan Fault may have begun movement in the Early Miocene. In the Late Miocene, thrusting occurred west of the southern Helan Shan and an unconformity developed between the Hongliugou and Qingshuiying Formations proximal to the the Cha-Gu Fault. Relationships between the Miocene stratigraphy and major faults in the region imply that during the Late Miocene the deformation front of the Qinghai–Tibetan Plateau had migrated to the Cha-Gu Fault along the western Ordos Margin, and the Xiang Shan was uplifted. Central-southern Ningxia was then incorporated into the northeast propagating thrust wedge. The driving force for NE propagation of the thrust wedge was most likely pronounced uplift of the northeastern plateau at the same time. Analysis of the sedimentary record coupled with consideration of the topographic evolution of the region suggests that the evolving fold-and-thrust belt experienced both forward-breaking fold-and-thrust belt development, and out-of-sequence fault displacements as the thrust wedge evolved and the foreland basin became compartmentalised. The documented sedimentary facies and structural relationship also place constraints on the Miocene-Recent evolution of the Yellow River and its tributaries.  相似文献   

18.
天山地区碰撞后构造与盆山演化   总被引:48,自引:0,他引:48  
研究表明,近东西向的天山造山带基本格架在古生代晚期已经初步形成;平行造山带广泛分布的二叠纪红色磨拉石证明当时造山隆升作用非常强烈,导致前陆盆地普遍发育。三叠纪,天山造山带遭受区域剥蚀夷平,盆山高差缩小,盆地规模进一步扩大。侏罗纪—古近纪,由于板内伸展作用,在准平原化的天山地区形成了一系列伸展盆地,呈近东西向分布。新近纪以来,受南面印度—欧亚陆—陆碰撞的影响,天山地区发生强烈陆内变形,以逆冲推覆和褶皱堆叠为特征;节理统计表明新生代的主压应力为南北方向。晚新生代,由印度和欧亚大陆碰撞产生的强烈挤压作用对大陆腹地的天山地区影响很大:前中生代块体发生剧烈隆升和褶皱,伴随大规模新生代坳陷的形成,导致盆山高差急剧增大;脆性剪切与挤压变形构造叠加在韧性变形的古生代岩层之上。同时,中生代拉伸盆地发生构造反转,形成新生代挤压盆地,盆山交接带变形以台阶状逆断层和断层相关褶皱为特征。由于盆地朝造山带的下插作用,使古生代的岩层呈构造岩片方式逆冲推覆在盆地边缘的中新生代岩层之上,当穿越不同地质构造单元时表现出不同的运动学特征。强烈挤压褶皱冲断是晚新生代盆山交接带的基本特征和最普遍的盆-山耦合方式,局部伴有小规模近东西向的走滑断层。中生代沉积岩的褶皱与断裂、侏罗纪煤层自燃及烧结岩的形成、强烈地震与断层活动、以及新疆独特的镶嵌状盆山格局,都是新近纪以来构造作用的产物。  相似文献   

19.
A series of balanced cross-sections across the Sub-Atlas thrust belt and the northern Ouarzazate basin are used to illustrate the structural geometry and the timing of deformation at the southern front of the High Atlas Mountains of Morocco. The selected area is among the best sedimentary records of mountain building of the entire orogenic system. The study of the relationships between thrusts and synorogenic continental formations enables the unraveling of kinematic sequences and the proposal of a relative chronology of deformation. Active thrusting in the area occurred in a rather continuous fashion from the Oligocene to the Pliocene, punctuated by a major erosional phase imprecisely placed in late Oligocene to early Miocene times. Detrital sedimentary facies indicate that uplift in the hinterland of the High Atlas, to the north of the Sub-Atlas belt, was taking place already by mid Eocene times, although it might have commenced locally even earlier. Within the Sub-Atlas zone, the exposed faults did not propagate in a simple piggy-back fashion but show evidence of a complex, synchronous sequence with events of fault reactivation and out-of-sequence thrusting.  相似文献   

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