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旋卷构造在地壳构造中,特别是在地壳局部构造中,是最普遍的构造型式.据李四光同志的分析,当外力的合力不通过某岩块的重心(质量中心)时,则此岩块将围绕核心部分(砥柱或旋涡)与周围岩块发生旋扭运动,以致产生旋卷构造.旋卷构造有许多类型,如果我们仅考虑其平面应力场,从其成生的构造应力场的推导过程中,除S型和反S型构造以及歹字型构造体系(它们可能与两种构造运动的联合作用有关)之外,都具有统一 相似文献
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在地质力学上以扭转变形为主的构造型式称旋扭构造,有涡轮状、帚状、莲花状构造等等。下面就此有关的内容讨论三个问题。 (一) 旋扭状构造的力学成因旋扭状构造是怎么形成的,也就是它是在什么样的应力场的作用下的产物?首先可从讨论无限平板在集中力偶作用下的应力分布着手。可通过一个简单薄膜的模拟实验来进行观察(图1)。当薄膜很大,力偶矩M作用范围不大的情况下,只在集中力偶附近产生涡轮褶皱,远离集中力偶作用处,看不出什么影响。由此可 相似文献
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双核型旋扭构造力学研究 总被引：2，自引：0，他引：2
本文提出了一种新的旋扭构造类型——双核型旋扭构造。它以具有两个砥柱为特点,区别于单核型旋扭构造。双核型旋扭构造旋回面组合形态最常见的有S形、反S形,其次有椭圆弧形、双曲线形,有时还可见涡轮状等。在野外构造研究基础上,文中提出了绕双砥柱旋扭运动的力学模型。采用流变学原理与方法,得到了这种构造型式的应力场与变形场的伯格斯粘弹性解析解。并进行了模拟实验。理论计算与实验结果表明,所提出的力学模型是合适的。 相似文献
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笔者提出了"旋卷状构造组合"(简称"旋卷状构造")的概念及其型式。旋卷状构造组合演变过程的研究表明,其成因与平行剪切作用下的普遍变形方式——层状岩石的层间走滑和褶皱作用密切相关;各组成要素形成于层间走滑和褶皱作用的不同发展阶段;不同的构造型式由不同的组成要素组合而成,它们都是这一演化过程中的系列产物,其中"涡轮状构造组合"为其最完整的构造型式。较为完整的旋卷状构造组合型式中还常具有核湾、两分面、切出虚脱区和扭折三角区等反映平行剪切成因特点的伴生构造特征。文章着重对其中最为完整的"涡轮状构造组合"的演变进程(模式)、鉴定标志及其形成时的平行剪切指向进行了探讨。 相似文献
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本文试图对旋卷构造应力强度与成煤矿化强度、成煤矿化强度与矿床至旋扭中心距离(r)的半定量关系,作一尝试性研究。结果表明,发耳偏心涡轮状构造控制着贵州省西部——云南省东部若干煤田的分布,是一种重要的控煤构造型式,其成煤矿化强度受构造应力场控制,其矿化强度高值区位处涡轮状构造应力中区,而成煤矿化强度与矿床至旋扭中心的距离(r)呈现一种类似正态分布的非线性函数关系。 相似文献
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旋卷构造是一种常见的和独特的构造型式,但并未得到应有的重视。笔者有机会去法国作短期考察,在阅读文献过程中,发现法兰西大部和西班牙西北部总体构造格局,与帚状构造一般形态相符。由于考察不是针对旋卷构造而安排的,看到的实际现象有限。现据有关材料和实际所见,对法兰西帚状构造要点,作简要报道。法兰西帚状构造展布范围,包括法国的阿莫尼干和中央高地,西班牙西北部的伊伯雷及上述地带环绕的大西洋海域。旋回带的收敛段在阿莫尼干,撒开段在中央高地,整体上呈现向西收敛、向东撒开,并向东北微凸的帚状形态。阿莫尼干地区发育着右行剪切的透入性构造,其中又集中形成三个右行韧性剪切带,同样显示 相似文献
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通过褶皱、断裂、节理、线理等构造形迹的系统观测对铜官山S状背斜的形成过程和机制进行了综合构造解析,发现该背斜经过了3次构造变形,2次构造叠加复合.早期NE向褶皱的S状弯曲是由于前期EW向断裂限制的结果;晚期S状弯曲是由于新华夏构造应力场导致轴近水平的麻花状旋扭的结果;还通过物理模拟和数字模拟验证了限制型及麻花型S状构造形成机制.值得注意的是,通过铜官山S状背斜的综合构造解析可以扩大到整体下扬子台褶带的构造演化力学解析.从而证明根据局部地区的构造综合解析才是认识区域大地构造运动方式、方向及其变化最直接、最可靠的证据. 相似文献
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普安旋卷构造体系及其控矿规律研究 总被引：3，自引：1，他引：3
本文通过1:20万区域地质调查等新资料的分析,对原普安联合构造体系的复合关系提出新的看法,初步认为,其中的旋卷构造为一自成体系的构造型式,它的形态特征、分布范围,随着资料的积累,已较清楚.文中对旋卷构造体系的控矿规律作了初步分析,可供区域矿产预测参考。 相似文献
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与北美不同,中国南方海相页岩层经历了多期构造改造,页岩储层物性受构造变形作用的影响较大。为了研究构造变形对南方海相页岩储层渗透率的影响特征和机理,以雪峰山西侧地区五峰-龙马溪组页岩为研究对象,利用气体脉冲衰减法、压汞法和扫描电子显微镜等手段对不同变形页岩样品的渗透率、孔隙结构及孔隙形貌特征进行了测试分析,探讨构造变形页岩的渗透率演化特征及其对孔隙结构演化的响应机理。测试结果显示,强烈构造变形页岩的渗透性较原生页岩和弱变形页岩的渗透性显著提高,强变形页岩样品的渗透率在0.2 mD和2.69 mD之间,比未变形和弱变形页岩样品的渗透率(在1.5×10-4 mD和1.7×10-3 mD之间)高三个数量级,表明强构造变形作用对页岩渗透率具有显著促进作用;同时,不同有效压力条件下页岩渗透率的演化特征显示,强变形页岩气体渗透率的压力敏感性比原生页岩和弱变形页岩显著降低。构造变形条件下页岩孔隙结构与渗透率相关性的进一步分析认为,强变形页岩的孔隙结构变化特别是大孔和裂隙的发育,是促进其渗透率增加的主要原因。这些研究结果表明,伴随强烈的构造变形,南方海相页岩易形成大孔和微裂隙发育的孔隙结构特征,有助于强变形页岩层渗透性的显著提高。构造变形页岩渗透率的提高有利于地质条件下气体的运移,一方面,将有利于页岩气往构造高点的迁移和富集从而形成游离气型或外源型页岩气甜点;另一方面,也可能导致页岩气在盖层条件不佳和断裂发育区的散失。 相似文献
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The north–south-trending upper reaches of the Minjiang River run along the Longmen Shan–Min Shan fault zone, a zone of abrupt topographic change along the eastern margin of the Tibetan Plateau. Multiple levels of well-preserved soft-sediment deformation structures (seismites) occur in sediments deposited in paleo-dammed lakes in the upper part of the Minjiang River Valley. These deformation structures include liquefied convolute deformation, water-escape structures, flame structures, pseudonodules, ball-and-pillow structures, sedimentary dykes, mud lenses, and large-scale folds. Several kilometers from the barrier bar of the Diexi paleo-dammed lakes, seven deformed structural layers were identified at different heights in late Quaternary stratigraphic sequences near Shawan Village, Maoxian County. Analyses of the deformation structures, landforms, and the structural environment indicate that these deformation structures were caused by earthquakes, slumps, and landslides.OSL (optical stimulated luminescence) and 14C dating of soft-sediment layers from the Shawan site indicate that intense earthquakes occurred during the period 25–20 ka B.P. Therefore, accurate geological dating of deformed features in dammed lake deposits in high mountains and canyons enables the record of moderate- to large-magnitude earthquakes to be extended to the late Pleistocene–Holocene upon the eastern Tibetan Plateau. 相似文献
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EMMANUELLE ARNAUD 《Sedimentology》2008,55(2):335-356
Recent studies on Neoproterozoic climate change have prompted renewed interest in Neoproterozoic glacial deposits and renewed debate over the criteria used to identify the nature of glacial influence on sedimentation. Analyses of soft sediment deformation structures have provided important clues to distinguish between competing palaeoenvironmental interpretations of Quaternary glacial deposits; a similar approach is presented here in the analysis of Neoproterozoic glacial deposits of the Smalfjord Formation, northern Norway. A detailed sedimentological and structural analysis at several sites in the Varangerfjorden area reveals complex soft sediment deformation at various scales in conglomerate, sandstone and diamictite. Deformation is predominantly ductile and includes anticlinal and synclinal folding, flow noses, flame structures, recumbent folding and shear structures. The deformed sediments are associated predominantly with conglomerate and sandstone, which record glaciofluvial and deltaic depositional conditions. Some deformations can be attributed to rapid deposition and slumping, whereas others appear to record shear stress associated with overriding ice. The scale, style and range of deformation, together with the coarse-grained nature of the deformed sediments and facies associations, suggest that these were unfrozen outwash sediments that were overridden by ice and resedimented in a dynamic ice-proximal setting. Whereas recent studies of diamictite-bearing strata of the Smalfjord Formation had revealed no clear evidence of glacial influence on deposition, deformation structures documented here suggest that glacial conditions prevailed on the basin margin during deposition of Smalfjord Formation sediments, with sedimentary facies and deformation structures typical of temperate ice-proximal settings. 相似文献
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B. G. Golionko E. V. Vatrushkina V. E. Verzhbitsky K. E. Degtiarev 《Doklady Earth Sciences》2017,475(1):719-723
Detailed structural investigations were carried out in the Pevek area in order to verify the tectonic evolution of the Mesozoic thrust and fold belt in Chukotka. South-vergent F1 folds in Triassic rocks were proved to be the earliest structures formed during the first deformation stage DI. These structures were deformed by north-vergent folds F2 that were formed during the second deformation stage DII. North-vergent folds are the main structures of the Jurassic–Lower Cretaceous complex. The fold structures of the first two stages are deformed by shear folds F3 finishing the stage DII. All these structures are deformed by submeridionally trending normal faults referred to the deformation stage DIII. 相似文献
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Recently discovered gold-rich mineral deposits in the eastern Nadaleen trend of northeastern Yukon Territory occur in unmetamorphosed Neoproterozoic carbonate and siliciclastic rocks and their location is partly controlled by structures. Regional deformation largely resulted from mid-Cretaceous NNE-vergent, thin-skinned fold-thrust activity. However, structures in the eastern Nadaleen trend are more complex and include strike-slip and reverse faults, and SSW-, W-, and E-plunging folds. Local structures are cospatial with regional geologic features, including (1) an E-striking structural triangle zone defined by oppositely dipping reverse faults that verge toward the eastern Nadaleen trend, (2) a transition zone between Paleozoic Ogilvie platform rocks in the north to Selwyn basin rocks in the south, and (3) a change in regional deformation character from west to east, whereby to the west, rocks in the south are more deformed than rocks in the north, whereas to the east, rocks show no obvious change in deformation style. The structural complexity within the eastern Nadaleen trend probably resulted from these regional geological features and was further complicated by local competency contrasts between rock units. The cospatial location of the regional geological features may have been caused by a pre-existing, W-trending subsurface basement structure. Reverse faults bounding the E-striking triangle zone may have acted as low permeability aquitards that directed mineralizing fluids up-dip into reactive carbonate stratigraphy in the eastern Nadaleen trend. Gold-rich mineral deposits in the eastern Nadaleen trend occur preferentially in SSW-plunging anticlines and near faults, both of which probably influenced the migration of mineralizing fluid. 相似文献
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受欧亚、印度—澳大利亚及太平洋三大动力体系的联合和复合作用,自中生代以来,华北能源盆地由周缘开始逐渐向盆内发育了复杂的盆-山耦合演化过程,形成了不同的构造变形和耦合演化特征。自西向东构造变形依次为西部稳定弱变形亚区、中部过渡变形亚区以及东部伸展变形亚区。同时,由西向东,构造变形由弱挤压至伸展,构造活动性由微弱到显著,且华北陆块东西两侧构造演化特征各不相同。华北能源盆地盆-山展布、耦合演化及其盆-山演化的动力学过程直接控制着盆地各种地质作用的发生和盆地类型及其演化,进而总体制约着能源矿产的赋存规律及成藏机制。 相似文献
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煤岩是一种对温度、压力等地质环境因素十分敏感的有机岩,地质演化过程中的各种构造-热事件必然导致煤岩发生一系列物理与化学结构的变化,并形成不同类型的构造煤。在构造应力作用下,煤岩不仅发生脆性和韧性变形,而且还产生不同程度的动力变质作用。因而,关于煤岩构造变形与动力变质作用的研究不仅具有重要的科学意义,而且在煤层气资源评价以及煤与瓦斯突出危险性预测方面也具有重要的实际意义。文中在已有研究成果基础上,通过对构造煤系列Ro,max、XRD和NMR(CP/MAS+TOSS)等测试和实验方法的对比研究,深入分析了煤岩不同构造变形和动力变质特征,进一步探讨了构造应力下煤岩动力变质作用的机理。研究成果表明,在构造应力作用下,煤岩脆性变形主要是通过破裂面上快速机械摩擦转化为热能而引起煤岩化学结构与其成分的改变;而韧性变形煤主要是通过局部区域应变能的积累而引起煤岩化学结构的破坏,从而发生不同机制的动力变质作用。 相似文献
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基性麻粒岩产于大陆地壳深部,它的研究可以为大陆岩石圈的性质、组成、演化和深部动力学过程提供重要信息。南天山库米什榆树沟地区发育总厚达1000多米的基性麻粒岩构造岩片,走向南东,朝北东推覆。剖面上和石炭纪蛇绿混杂岩共存,并发生了石榴子石的旋转变形和强烈的石英-长石矿物相韧性变形。然而它们的变形条件至今尚未被研究。本文运用透射电镜(TEM)超微组构技术对榆树沟基性麻粒岩中石英和石榴子石进行了详细研究,结果表明,石英中存在着丰富的超显微变形构造,自由位错、亚颗粒和位错网非常发育,这表明研究区基性麻粒岩在折返抬升过程中曾遭受过较强的石英-长石相韧性变形作用;石榴子石中的超微变形构造则极为少见,只在其中发现几根自由位错,并在其颗粒边缘发现少量亚颗粒构造,说明该矿物主体属于脆性变形。这两种矿物变形性质的差异,反映了石榴子石的晶体结构在该条件下比石英更稳定,而且说明石榴子石的变质温度没有超过900℃,也就是说,本区麻粒岩的变质作用并非发生在极高温度的条件下。 相似文献
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嫩江—黑河构造带地处松嫩地块与兴安地块的结合部位,一直以来是业内学者关注的焦点。在构造带内内蒙古莫力达瓦旗哈达阳一带野外实地调研过程中,发现一套变质变形程度与周围地质体差异很大的地层。岩石组合为绿泥石白云母构造片岩、二云母微晶片岩、黝帘白云糜棱片岩等。采用LA-ICP-MS技术获得的绿泥石白云母构造片岩中锆石U-Pb年龄为413.9Ma±2.7Ma。通过分析区域地质演化历史及不同时代地质体特征,认为沿红山梁—哈达阳—依克特一带存在一条构造混杂堆积岩带,这套强变形岩石应为构造混杂岩带的一部分,其原岩形成时代为早泥盆世,后期构造定位应与嫩江—黑河构造带最后于早石炭世末拼合作用有关。 相似文献