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1.
莺歌海盆地坡折带特征及其对沉积体系的控制 总被引：10，自引：1，他引：9
坡折带是层序样式划分的重要依据.大量地震剖面的精细解剖表明, 莺歌海盆地坡折带可划分为构造坡折带和沉积坡折带, 进而将层序构成样式划分为四类, 即挠曲坡折型、断裂坡折型(生长断裂型)、沉积坡折型(陆架陆坡型, 相当于Ⅰ类层序)和缓坡型.不同类型层序样式控制不同低位体的空间分布.挠曲坡折、断裂坡折和沉积坡折控制了各三级层序中斜坡扇和盆底扇的分布, 而缓坡控制强制性海退型低位三角洲的分布.详细的构造研究表明, 莺歌海盆地裂后期边缘断裂, 如①号断裂和莺东断裂在不同时期不同部位仍表现出程度不同的活动性.正是由于这些断层的活动性及其在空间上的差异性, 控制了盆地内坡折带的发育. 相似文献
2.
跨断层的隧道结构在汶川地震中破坏严重,这说明传统的抗减震技术已不能保证高烈度地震区隧道结构的安全。为此,研发了可变形抗减震措施。通过振动台模型试验,考察了采用该类型措施的隧道结构地震响应特征与震后破坏形态。结果表明：跨断层隧道结构设置减震缝,可以有效减小结构的内力值和应变值;套管式可变形结构可以有效保护主套管上部结构和被套管,但主套管下部结构破坏严重;套管式可变结构提高了隧道的防水性且震后易于修复,整体性能优于减震缝;采用可变形抗减震结构的同时,必须提高衬砌混凝土的强度;不论采用何种抗减震措施,隧道结构的拱脚和仰拱是抗震加固的重点部位。研究成果可以为高烈度地震区隧道结构的抗震设防提供参考。 相似文献
3.
张家口一蓬莱断裂带是一条北西西向活动断裂带。本文选取ETM+光学影像和SRTM高程影像作为主要数据源,结合研究区已有地质资料研究发现该带断裂构造的北西西向线性特征明显。从水系分布和错断地形等地貌标志判断,该断裂具有左阶组合样式和左行走滑活动特征。据遥感影像综合特征,可将该带分为张家口段、延庆-怀来段和北京一天津段,影像特征分段性显著,并与断裂带的分段性一致。研究结果表明,张家口-蓬莱断裂具有左行走滑的运动学特征,限制或错断北北东或北东向断裂,并且控制该区域的左阶雁列式第四纪盆地群和第四纪冲洪积物的分布。该断裂带各段对不同规模的水系分布和形态影响比较大,且北京-天津地区的华北平原段断裂对第四纪冲洪积扇和沿海地区的贝壳堤的形态和分布有一定的控制作用。地球物理深部数据和野外地质考察资料也证实了遥感解泽的结果,证明遥感技术在探查断裂构造空间展布和活动性鉴定中有着广泛的应用前景。 相似文献
4.
李军辉 《吉林大学学报(地球科学版)》2012,42(4):961-969
分析在不同构造背景下发育的层序构成样式,可以更加精确地预测有利勘探区带和油气藏。利用地震、钻井、测井、岩心以及古生物等资料,依据层序界面特征,将呼和湖凹陷下白垩统划分为3个二级层序、5个三级层序。依据构造背景,将研究区划分出断控陡坡带、缓坡断阶带、洼槽带等3种构造单元,在此基础上分不同构造单元建立了相应的层序构成样式:断控陡坡型层序构成样式、缓坡断阶型层序构成样式、洼槽型层序构成样式。研究结果表明,不同的构造单元具有各自特征的层序构成样式和沉积体系域构成模式,不同类型层序构成样式也决定了不同的构造单元具有不同的油气成藏模式。在断控陡坡带主要发育断层-岩性和断鼻型油气藏,在缓坡断阶带发育断层-岩性和地层超覆型油气藏,在洼槽带主要发育自生自储型的透镜体油气藏;此外,洼槽边缘可发育断层-岩性型油气藏。 相似文献
5.
Because of insidious fault’s concealing performance and lagging nature, water inrush from insidious faults in coal seam floor can cause great threads to the mine safety. Based on analyzing the engineering geology conceptual model, this paper simulated the insidious fault lagging water inrush process and showed the lift height of the confined water in the insidious fault fractured zone (LHCWIFFZ) and the formation of water inrush channel. Then the concept of the potential water inrush channel with time effect was put forward. In order to further illustrate the time effect of the lagging water inrush from insidious fault, theoretical analysis was made from two aspects of the time effect of the plastic zone development height in the insidious fault fractured zone (PZDHIFFZ) based on the differential flow deformation theory and the time effect of water inrush channel in the upper part of the insidious fault (WICUPIF) based on the subcritical crack propagation theory. Simulation results showed that the results are basically consistent with mining practice. 相似文献
6.
《Journal of Structural Geology》1999,21(8-9):1065-1070
If faulting is treated as a stress-controlled phenomenon, the generation of a single fault set, or two sets in conjugate arrangement are inevitably predicted implying plane strain. Alternatively, considering faulting as a strain-controlled process, multiple-set patterns can be predicted. The analysis of multiple-set patterns requires identifying the type of fault pattern from four possibilities: Coulomb, isolated, orthorhombic and complex fault patterns.There are techniques that permit a unique solution of strain tensor for Coulomb and orthorhombic fault patterns. For isolated fault patterns, the principal paleostress directions could be used to approximate the principal strain directions. In this case, we need to assume a homogeneous stress field, independence between faults, and parallelism between shear stress and slip vector on the sliding plane.For complex fault patterns, it is not possible to uniquely determine the total strain tensor without knowledge of all the slip planes. Furthermore, inverting fault-slip data to determine the stress tensor is not correct because the assumptions of the inversion methods are not satisfied. Only a rough approximation is possible assuming that strain produced by major faults represents the total strain tensor. 相似文献
7.
F. Mirabella M.G. Ciaccio M.R. Barchi S. Merlini 《Journal of Structural Geology》2004,26(12):2233-2249
Normal faults within orogenic belts can be pre-, syn- or post-orogenic features. We studied the Gubbio normal fault (central Italy), which is an example of a pre-orogenic fault reactivated in a post-orogenic stage. The Gubbio Fault is a 22-km-long fault bordering a Quaternary basin and part of an active faults system in the Umbria–Marche region (Central Italy). The interpretation of a set of seismic profiles enables us to reconstruct the fault geometry in detail and to measure displacement and throw distributions along the fault strike. Seismic data indicate that the Gubbio Fault represents an example of multiple reactivation: at least a portion of the fault was active in the Miocene and only a part of the total displacement was achieved in the Quaternary. The reconstruction of the fault geometry at depth shows that the fault is characterised by listric geometry. The fault is also characterised by a bend along strike and structure contours show that this geometry is maintained at depth. As the fault is commonly addressed as presently active, the maximum fault dimensions are correlated to the maximum expected earthquake, and the presence of the fault bend is discussed as a possible barrier to seismic ruptures propagation. 相似文献
8.
Strike–slip faults are often accompanied by a variety of structures, particularly at their tips. The zones of additional fracturing are classified as tip‐damage zones. These zones can be subdivided into several different damage patterns based on the nature and orientation of faults and fractures developed. Damage zones at the ends of small strike–slip faults (mode II tips) develop wing cracks, horsetail splays, antithetic faults, synthetic branch faults and solution surfaces. Similar tip‐damage patterns are also commonly observed at larger (regional) scales, but with a dominance of faulting over tensile cracks and solution surfaces. Wing cracks and horsetail splays developed at small‐scale faults are replaced by normal faults in large‐scale faults. Antithetic faults and synthetic branch faults are observed at small and large scales. Thrust faults are developed at large scales, in a similar pattern to solution surfaces at a small scale. All these structures may show slightly different angular relationships to the master fault at small and large scale, but develop in response similar stress distribution and mechanics around the fault. Thus, mode II tip‐damage zones show similar patterns over a wide range of fault scales. 相似文献
9.
Interpretation of seismic data from the Lufeng Sag of the Pearl River Mouth Basin (PRMB) in the northern part of South China Sea shows that different intersection patterns developed in the cover units above basement normal faults. A series of analogue models are used to investigate the intersection patterns and deformation in the sedimentary cover sequences above a basement horst bounded by two non-parallel faults. Modelling results show that during their upward propagation, the basement faults may intersect within the cover sequences and form a graben above the basement horst. Length and width of the graben increase with cover thickness. The strike and dip intersection points are controlled directly by the thickness of the cover sequences, dip and strike of the basement faults, and width of the basement horst. The intersection point migrates along the axis of the graben toward the wide end of the basement horst, when the cover sequence thickens. In contrast, it migrates toward the narrow end of the basement horst, where both fault dip and angle of strike difference increase. The intersection point moves upward with increasing width of the basement horst crest. Model profiles also indicate that in the presence of a ductile layer between the cover and basement such intersection patterns do not form. Interpretation of seismic data and model results show that the intersection pattern developed in the Lufeng Sag is a result of propagation of basement faults into cover units during different extension stages of the basin. Results of this study can be applied to many other sedimentary basins where such fault intersection patterns are likely to form when non-parallel conjugate basement faults are active during sedimentation. 相似文献
10.
Shunshan S. Xu Ángel F. Nieto-Samaniego Susana A. Alaniz-Álvarez Luis Germán Velasquillo-Martínez 《Central European Journal of Geosciences》2011,3(1):29-36
Rotation of faults or pre-existing weakness planes produce two effects on the slickenlines of fault planes. First, the rotation leads to changes in the pitch of slickenlines. As a result, the aspect of the pre-existing fault may change. For example, after rotation, a normal fault may show features of an oblique fault, a strike-slip fault, or a thrust fault. Second, due to rotation, stress states on the fault planes are different from those before the rotation. As a consequence some previous planes may be reactivated. For an isolated plane, the reactivation due to rotation can produce new sets of slickenlines. With block rotation, superimposed slickenlines can be generated in the same tectonic phase. Thus, it is not appropriate to use fault-slip data from slickenlines to analyze the stress tensor in a region where there is evidence of block rotation. As an example, we present the data of slickenlines from core samples in the Tunich area of the Gulf of Mexico. The results wrongly indicate that the calculated stress tensor deviates from the far-field stress tensor. 相似文献
11.
2008年汶川Ms8.0级强震触发了体积近12×108 m3的大光包滑坡。该滑坡发生于古生代碳酸盐岩地层,滑带地质背景为斜坡内部深埋400 m、最大厚度达5 m的先期层间构造错动带。最新调查表明,该错动带是斜坡内部地下水通道,错动带岩体处于饱和状态。为揭示强震过程与地下水相关的大光包滑坡启动机制,提出了一种具有软弱层带的硬质碳酸盐岩边坡简化模型,将层间构造错动带概化为碳酸盐岩硬层内部软弱层带,采用FLAC3D程序中的流固耦合算法模拟了模型的响应特性。研究结果表明:强震过程中软弱层带上下碳酸盐岩硬层的变形响应时间、波型、大小出现明显差异,上硬层相对于下硬层产生了张离、压缩和剪切3种非协调变形模式,由此对软弱层带产生了振动冲压-张拉和振动剪切动力学行为,饱水软弱层带形成了具有瞬间放大和累积增涨特征的超孔隙水压力。这里将上下硬层差异性变形称为非协调变形,认为非协调变形是软弱层带应力放大成因,推测软弱层带应力瞬间放大以及放大应力长持时作用下的岩体致损是超孔隙水压力激发和累积的成因;强震过程软弱层带超孔隙水压力导致其内有效应力快速降低,使得斜坡前部锁固段应力快速集中,而后被突然剪断,滑坡骤然启动,揭示了强震过程中超孔隙水压力是大光包滑坡启动的主要原因。 相似文献
12.
对断裂数据化处理,得到断裂控制点。以断裂控制点为约束,对断裂进行点插值,以单个统计单元为视窗,统计落入不同栅格内的插值点数目,进而求得插值点落入不同栅格的概率,对变量数据拟合,得到断裂信息维以及相关系数。将该思路应用在金湖凹陷阜二段断裂分形评价中,分别计算了断裂长度信息维、面积信息维。结果表明,90%以上的统计单元相关系数0.9,断裂发育区具有较高的自相似性,断裂总体分形特征曲线的相关系数0.999。金湖凹陷断裂的计算表明,该思路是测量断裂信息维的有效方法,能够提高工作效率,具有较好的应用前景。 相似文献
13.
断层纵向输导与储层非均质性耦合控运模拟实验研究 总被引：4，自引：1，他引：3
在物理模拟实验的基础上探讨了断层输导能力与储层非均质性对油沿断层垂向运移和侧向分流的控制机理与模式。研究结果表明,断层输导能力与储层非均质性对油运移的控制本质上表现为“物性”（断层与储层渗透率比值）与“动力”对油垂向运移和侧向分流的耦合控制作用。两者对油的运移和纵向分布的耦合控制作用可概括为强输导能力断层-反韵律储层控运、弱输导能力断层-反韵律储层控运和强输导能力断层-正韵律储层控运3种模式。第一种模式中,油沿断层垂向运移的过程中不易侧向分流,油主要富集在直接位于区域性盖层之下的储层中;第二种模式中,油沿断层垂向运移的过程中较易侧向分流,油在纵向上各储层中均有一定的富集;第三种模式中,油沿断层垂向运移的过程中极易侧向分流,油大多富集在下部物性最好的储层中。 相似文献
14.
《Journal of Structural Geology》1988,10(2):183-192
Displacement analyses along thrust faults of different maturity (or size) reveal maxima and minima, often associated with minor folding of the adjacent beds, between the tip points. The results show that these faults are segmented, and that they formed through the linkage of smaller (previously independent) faults, and (or) by propagation of a single fault affected by the existence of barriers. Points of potential linkage (marked by displacement minima) are fault bends or distinct fault breaks. Fault nucleation (marked by displacement maxima) occurs within the planar segments of a fault; only in one of eight examples is the nucleation point seen to occur at a fault bend.Displacement variations along inferred or extrapolated regional-scale thrust faults show a variety of patterns, most of which involve constant displacement or a monotonic increase or decrease away from the basal décollement. These data are not considered to be as reliable as those from observed thrusts due to the necessary subjectivity involved in the extrapolation process.In general, displacement variation appears to be a reflection of the symmetry of the thrust fault system, such that, for example, a flat-ramp geometry ending in a steep tip will show an asymmetrical displacement function skewed toward the surface, with a nucleation point above the basal décollement. 相似文献
15.
利用Instron1342型电液伺服材料试验机,采用双扭常位移松弛法对花岗岩试件在空气中及饱和水两种条件下进行了亚临界裂纹扩展试验研究,获得了相应的裂纹扩展速率V与应力强度因子KI的关系（KI -V曲线）及亚临界裂纹扩展参数,讨论了两种环境下裂纹亚临界扩展的规律,并对两种环境下亚临界裂纹扩展参数进行了对比分析。研究表明：采用常位移松弛法所测试的两种条件下的lgKI -lgV关系都有很好的线性规律。在双对数坐标空间中,含饱和水试件的lgKI -lgV曲线位于空气中试件lgKI -lgV曲线的左上角,曲线斜率减小,而截距增加。在同一应力强度因子水平上,含饱和水试件的裂纹扩展速度大,说明水能加速亚临界裂纹扩展,与实际相一致。 相似文献
16.
The tectono-geochemistry method as a lithogeochemical exploration tool is a process centric approach based on the premise that element migration and concentration within and adjacent to geological structures are controlled by large-scale dynamic earth processes that operate on a variety of scales to focus mass and energy flux. Here we present a case study of the Gaosong tin-polymetallic deposit, Gejiu district, SW China, illustrating how the tectono-geochemistry method can be applied to mineral prospectivity mapping. As a first step, 2216 fault rock samples collected within the Geiju district were assayed followed by a detailed examination of the assay results by means of factor analysis and multifractal singularity mapping. The main aims of these analyses were to (1) statistically explore the data with respect to specific element concentrations, associations and geochemical patterns by which the fault rock samples can be grouped, (2) better characterize the samples in terms of whether or not the rocks recorded any evidence for hydrothermal mineralization processes, and (3) identify any geochemical anomalies that may present vectors to buried ore. The results illustrate that element distribution patterns are greatly influenced by fault permeability and that NE-SW-striking faults are the most favorable in terms of concentration of ore elements. Factor analysis greatly assisted the identification and interpretation of, for example, element associations, and geochemical zonation patterns genetically related to intrusions. Recognition of singularities was of particular importance with respect to identifying and delineating primary fault tectono-geochemical anomalies that may be caused by buried ore. Of particular interest are low singularity values as these correspond with positive geochemical anomalies over known ore deposits in the Gejiu district. Anomalies delineated by local singularity exponents may represent undiscovered ore and, thus, warrant further exploration. 相似文献
17.
Scan C. Mulshaw 《Journal of Geochemical Exploration》1996,56(3):265-277
This paper discusses the results of a light hydrocarbon gas (LHG) lithogeochemical survey carried out at Shannonbridge in central Ireland. Two methods of LHG extraction (dry grinding and sample solution in EDTA) are compared with a heat extraction method developed by Carter (1981). The results show that due to a more complete breakdown of the sample, LHG contents of up to an order of magnitude greater are released by grinding and sample solution, with no apparent decrease in precision. As a result, a potential problem related to the generation of additional gases by the thermal breakdown of organic matter during heating, can be avoided.Similar LHG component distribution patterns are produced by dry grinding and EDTA extraction suggesting that both methods could be useful alternatives to the heating technique. This is strengthened by the identification of a possible target zone in Shannonbridge based on the distribution of samples depleted in methane and enriched in butyl gases, C4 (butane plus butene plus their associated isomers). However, this empirical interpretation was not supported by the results of heating. Furthermore, subsequent exploration failed to establish the presence of a significant mineral occurrence at Shannonbridge. Evidently, the LHG patterns were either misinterpreted or they reflect hydrocarbon sources which are not related to mineralisation.Further evaluation of the data showed that LHG component distributions are significantly influenced by variations in lithology. Once this effect was reduced, it became apparent that the patterns are principally controlled by regional faulting. Since fault structures would be permeable to hydrocarbon gases formed from a variety of processes (such as maturation of organic matter in the host limestones), no relationship with buried mineralisation is necessary to explain the patterns observed.By using the Shannonbridge data as an example, this paper attempts to emphasise the equivocal nature of data collected using prospecting methods of this type. The aim is not to refute innovative and quality research already carried out in this field because the association of hydrocarbon gases with mineralisation is too frequent to be simply classified as coincidental. However, anomalous levels of LHG can be attributed to other processes which, in many cases, are too easily overlooked. 相似文献
18.
利用地面LiDAR精细化测量活断层微地貌形态——以毛垭坝断裂禾尼处断层崖为例 总被引：1，自引：1，他引：0
受地壳内部持续运动和沉积、风化等自然动力及人类生产与生活活动影响,活断层微地貌形态往往比较复杂,传统测量方法较难快速、高效地获取大范围内精细化的活断层微地貌形态,激光雷达扫描技术的出现和发展为活断层微地貌的精细化与定量化研究提供了新的技术手段。以川西理塘毛垭坝盆地北缘的正断层崖为研究对象,利用地面LiDAR获取活断层微地貌高精度点云后,经过点云配准、滤波、重采样和三角构网处理后,建立了0.05 m分辨率的数字高程模型和真彩色三维模型,在此基础上分析了断层崖地貌特征,并获取了正断层错动两期最新地貌面的精确垂直位错量。研究结果表明,地面LiDAR技术是精细测量活断层微地貌形态和量化相关地貌特征参数的有效手段,提高了活断层微地貌形态测量的精度和认识水平。 相似文献
19.
The post-construction settlement of rockfill dams and high filled ground of airport, which is a phenomenon of much significance, is mainly caused by the time-dependent breakage of the rockfill material. In this paper, a random virtual crack DEM model is proposed for creep behavior of rockfill in PFC2D according to the theory of subcritical crack propagation induced by stress corrosion mechanisms. The bonded clusters are adopted to represent the rockfill particles so as to simulate their irregular shapes. Virtual cracks are set at the bonds of the clusters, and the length of the crack is considered as a random value, which leads the crushing strength of a single particle to follow the Weibull’s statistical model and the corresponding size rules. Oedometric creep tests for rockfill are simulated by using this proposed model. The results show that the model, validated preliminarily by some test data, can reflect qualitatively the creep mechanism as well as the size effects reasonably. Particles can develop various breakage patterns during creep, including global breakage, local breakage and even complex mixed breakage. The increase in stress levels and particle size will lead to an obvious growth of the creep strain and creep rate of the rockfill. The scale effects on the creep behavior of rockfill are analyzed through 35 specimens, and formulas including the effects of scales and stress levels are tentatively proposed. 相似文献
20.
通过对恭城－栗木裂带中断层岩的研究，确立了一种新型断层角砾岩－断溶角砾岩的存在。断溶角砾岩兼具断层角砾岩和岩溶角砾岩的特点，是断裂和岩溶塌陷共同作用的产物。这种角砾岩的角砾分为断层角砾和溶洞崩塌角砾两种，角砾及胶结物中均发育有方解石e双晶等应力作用的产物，它形成于地下5－8km深的脆性变形环境中，并记录了断裂带的多期活动及运动方向和应变型式。对断溶角砾岩的研究有利于恢复恭城－栗木断裂带的形成及其演化历史。断溶角砾岩形成模式的提出揭示了研究区与断裂伴生的地下溶洞的分布形成、发展及灭亡的规律，这对于减少或防止因溶洞塌陷而带来的地质灾害具有重要意义。 相似文献