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RésuméDes structures synsédimentaires de type dish-structure, plis disharmoniques, figures de charge, dislocation et des destructions du litage et intrusions sableuses, observées dans le Saïss, sont interprétées comme des structures induites par une liquéfaction sismique de sables marins et fluviátiles, parfois associée à des injections sableuses. La place de ces structures parmi les divers types de séismites est discutée par rapport à l’influence des caractéristiques de granulométrie, de diagenèse et de pente qui conditionnent les différents modes de déformation. Les deux niveaux déformés marocains sont replacés dans le déroulement de la tectonique pliocène au sud du Rif. © Elsevier, Paris 相似文献
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震积岩是灾变性事件岩的典型代表,是具有震积构造和震积岩序列有一定成因联系的一组岩石的总称。成都金沙遗址区全新统地层中首次发现震积岩,该地层自下而上为底部砾石层、中部暗色(含炭)泥质层、上部褐黄色土壤层,整体属河流冲积物。通过野外观察,研究区发育一组走向SE120°的正断层,断层两盘的底部砾石层顶界面有明显的错断。构成地垒构造;在IT6511、IT6610层位中的断层带中见明显阶梯状断裂,其以张性正断层为主,断距约为10~90cm。在靠近阶梯状断裂的IT6512、IT6613-6614层位中发现一系列地震成因的软沉积物变形标志及破裂构造,包括砂土液化(脉)、液化卷曲变形构造、负载构造、微断裂、地裂缝、震塌岩等。分析认为这些软沉积物变形标志及破裂构造是由同期地壳活动引起的地震作用形成的。金沙遗址区震积岩的发现,对研究四川盆地全新世以来的古环境有重要意义。 相似文献
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鲁中寒武系馒头组震积岩的发现及初步研究 总被引：25，自引：4，他引：25
近几年在鲁中不同地区发现馒头组石店段中均有震积岩产出。震积岩形成于干燥的潮坪泻湖环境，发育在下寒武统的上部。它们具有记录强地震事件的泄水构造（地震成因泥晶脉）、液化卷曲变形、阶梯状小断裂、层内错断和液化网状裂纹等层内构造的特征。本文通过地层综合对比，论证了不同地区震积岩的等时性。认为：鲁中早寒武世末有一个地震活跃期；地震序列属乔秀夫（1994，2001a)提出的碳酸盐岩振动液化地震序列的原地系统；震积岩分布范围是约在510Ma前，以古郯庐带为震中的强地震之7－11度烈度区。为区别于张增奇（1996）提出的鲁中新元古代石旺庄期地震事件层，将此地震成因地层名之为馒头期地震事件层。 相似文献
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Claudia Migowski Amotz Agnon Revital Bookman Jörg F.W Negendank Mordechai Stein 《Earth and Planetary Science Letters》2004,222(1):301-314
A high-resolution Holocene seismic history of the Dead Sea Transform (DST) is established from laminated sedimentary cores recovered at the shores of the Dead Sea. Radiocarbon dating and annual laminae counting yield excellent agreement between disturbed sedimentary structures (identified as seismites) and the historical earthquake record: All recent and historical strong events of the area were identified, including the major earthquakes of A.D. 1927, 1837, 1212, 1033, 749, and 31 B.C. The total of 53 seismites recognized along the entire Holocene profile indicate varying recurrence intervals of seismic activity between a few and 1000 years, with a conspicuous minimum rate at 2100-31 B.C. and a noticeable maximum during the past six to eight centuries. Most of the epicenters of the correlated earthquakes are situated very close to the Dead Sea (within 150 km) or up to 400 km north of it along the DST. Between 1000 B.C. and A.D. 1063, and from A.D. 1600 to recent time the epicenters are all located on the northern segment of the DST, whereas prior to 1000 B.C. and between A.D. 1000 and 1600 they appear to scatter along several segments of the DST. We establish how the local intensity exerts a control on the formation of seismites. At historically estimated intensities greater than VII, all well documented earthquakes are correlated, whereas at intensities smaller than VI none are matching.The periods with enhanced earthquake rate along the DST correlate with those along the North Anatolian Fault as opposed to the intervening East Anatolian Fault. This may indicate some elastic coupling on plate-boundary scale that may also underlie escape and extrusion tectonics, typical of continental collision. 相似文献
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Soft‐sediment deformation occurs in ancient eolian dune deposits, but understanding its extent and the conditions and forces behind the deformation often remains elusive. Here we gain insight into the aerial extent and environmental conditions related to intense soft‐sediment deformation, based on an exceptional three dimensional (3D) exposure of eolian dune deposits and preserved geomorphic landscape expressions in the Jurassic Navajo Sandstone at White Pocket, Vermilion Cliffs National Monument, Arizona. Deformation features include elongate northeast trending decameter‐scale mounds and raised ridges cored by deformed and upturned eolian dune sets, overlain by a massive blanket sandstone with breccia blocks. The geomorphic mounds display ~40–60 m spacing, roughly perpendicular to the southerly paleoflow dune foreset directions. The geometry of the deformation is imaged by oblique aerial photography using cameras mounted on a remote control airplane and high resolution panoramas with a robotic camera mount. We interpret the exquisitely preserved deformation features as liquefaction‐induced ground failure, consistent with theoretical and laboratory studies of deformation in saturated sand. A shallow water table affected by differential dune loading facilitated lateral spreading and failure. The transition to steady‐state flow liquefaction near the top of the shallow water table destroyed original sedimentary structure, creating a massive sand blanket that entrained brecciated blocks ripped up during flow. The water‐pressurized, upwelled sediment created the mounds (a relief inversion). In underlying deformed dune sets, deformation was intense but sedimentary structure was not obliterated as deformation progressed from initial cyclic mobility to strain‐softening, but ceased prior to steady‐state flow liquefaction. The spatial extent, topographic relief, and intensity of dynamic deformation suggest an origin of strong ground motion driven by long‐duration surface waves of a large earthquake (> Mw 7–8), possibly related to back arc thrusting from Jurassic subduction of the Pacific plate under North America. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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川西南荥经坳陷开展了多口页岩气调查井及参数井(CYY1,YD1和YD2)的钻探。通过大量岩心观察和沉积构造特征分析,在中下奥陶统识别出大量软沉积变形构造及脆性变形构造,包括重荷模、火焰构造、球-枕构造等负载相关构造,液化砂岩脉、液化泥砾等液化构造,以及布丁构造、卷曲变形、震裂缝、震裂角砾、同沉积断层等,具有典型地震导致的同生及准同生构造变形特征。记录显示至少发生了2次地震事件,并引发海啸以及多次余震。该区震积岩的发现表明早中奥陶世曾发生明显的构造活动,是加里东早期都匀运动一次构造运动幕的响应,这对川中隆起具有重要意义。构造运动导致荥经坳陷周缘断裂活动并引发地震。地震对沉积地层的改造极大地改善了研究区油气储集层条件,更利于油气的运移。 相似文献
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二连盆地白音查干凹陷下白垩统震积岩的发现及其地质意义 总被引：4，自引：0，他引：4
二连盆地白音查干凹陷下白垩统钻井取芯中发现有变形和开裂两类特殊地质现象。同沉积塑性变形和碟状构造属于
变形,微断层、网状裂缝、砂岩岩脉、角砾岩为开裂。这些地质现象具有震积岩的特征,多由外界振动引发。变形多发生
在沉积物未固结—半固结阶段,开裂发生在沉积物成岩后。微断层、网状裂缝和砂岩岩脉形成于拉张应力作用下。这些特
殊地质现象多出现在腾格尔组和都红木组一段,而且从下往上,由开裂向变形演化。这与当时区域伸展构造背景和地震、
构造活动有关,地震、构造活动较为强烈时容易产生开裂现象,地震、构造活动较为微弱时容易产生变形。 相似文献
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通过对东濮凹陷北部古近系沙河街组的大量岩心观察和区域沉积-构造演化的分析,认为原地形
成的震积岩普遍发育,以独具特色的软沉积物同生变形构造为主,主要有液化砂岩脉、火焰构造、枕状构造、
球-枕构造、假结核、泄水构造、液化卷曲变形构造、液化水压破裂构造和粒序断层等,并综合出原地形成的
震积岩软沉积物同生变形构造的垂向序列,自下而上依次为液化砂岩脉段、液化角砾岩段、液化卷曲变形段、
震塌岩段以及液化均一层段,而球-枕构造和液化砂岩脉的形成主要与厚层泥岩夹砂岩有关,在震积序列的各
部位均可出现。在东濮凹陷古近系沙河街组中识别出液化角砾岩、震褶岩、震塌岩 ３种类型的震积岩。震积岩
的识别,为长期以来人们对东濮凹陷古近系沙河街组砂体沉积的 “ 重力流”与 “ 牵引流”以及相应盐岩成因的
“ 深水成盐”与 “ 浅水成盐”的争论,从岩石学特征方面提供了一些肯定或否定的证据,使这些问题逐渐趋于
明朗化。另外,震积岩是潜在的有利储集体,可能为东濮凹陷的勘探开发提供一个新的方向。 相似文献