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笔者总结了近年来的研究成果认为．中国东部的郯庐断裂带白海西期以来经历了两个主要发展阶段：第一阶段是广义的郯庐断裂带发展阶段，晚三叠世-早侏罗世由于扬子地块与华北地块的碰撞，成为两地块的对接边界，具有逆冲推覆的性质，属广义的特提斯构造域。第二发展阶段从早白垩世以来，发展成为一条平移断裂带，属于狭义的环太平洋构造域的平移系统。岩相古地理资料显示了扬子地块与华北地块的对接始于晚二叠世早期：印支期的郯庐断裂带是一条由NE、NNE向展布的缓‘S’型的地块拼贴边界．在现今的郯庐断裂带上表现为残留的由北北西向南南东的斜向逆冲推覆的性质，中下构造层次表现为韧性逆冲推覆变形，上部构造层即前陆褶皱冲断带内的变形：应力场分析资料显示：早三叠世晚期开始地表浅部就有近南北向的挤压作用，左行走滑平移作用开始发育：早白垩世晚期开始转入引张伸展阶段．与中国东部的伸展作用一致：新近纪又转为近东西向挤压．发育逆冲兼右行走滑作用． 相似文献
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AbstractThe Karasu Rift (Antakya province, SE Turkey) has developed between east-dipping, NNE-striking faults of the Karasu fault zone, which define the western margin of the rift and westdipping, N-S to N20°-30°E-striking faults of Dead Sea Transform fault zone (DST) in the central part and eastern margin of the rift. The strand of the Karasu fault zone that bounds the basin from west forms a linkage zone between the DST and the East Anatolian fault zone (EAFZ). The greater vertical offset on the western margin faults relative to the eastern ones indicates asymmetrical evolution of the rift as implied by the higher escarpments and accumulation of extensive, thick alluvial fans on the western margins of the rift. The thickness of the Quaternary sedimentary fill is more than 465 m, with clastic sediments intercalated with basaltic lavas. The Quaternary alkali basaltic volcanism accompanied fluvial to lacustrine sedimentation between 1.57 ± 0.08 and 0.05 ± 0.03 Ma. The faults are left-lateral oblique-slip faults as indicated by left-stepping faulting patterns, slip-lineation data and left-laterally offset lava flows and stream channels along the Karasu fault zone. At Hacilar village, an offset lava flow, dated to 0.08 ± 0.06 Ma, indicates a rate of leftlateral oblique slip of approximately 4.1 mm?year?1. Overall, the Karasu Rift is an asymmetrical transtensional basin, which has developed between seismically active splays of the left-lateral DST and the left-lateral oblique-slip Karasu fault zone during the neotectonic period. © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
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《Geodinamica Acta》2001,14(1-3):197-212
The Karasu Rift (Antakya province, SE Turkey) has developed between east-dipping, NNE-striking faults of the Karasu fault zone, which define the western margin of the rift and west-dipping, N–S to N20°–30°E-striking faults of Dead Sea Transform fault zone (DST) in the central part and eastern margin of the rift. The strand of the Karasu fault zone that bounds the basin from west forms a linkage zone between the DST and the East Anatolian fault zone (EAFZ). The greater vertical offset on the western margin faults relative to the eastern ones indicates asymmetrical evolution of the rift as implied by the higher escarpments and accumulation of extensive, thick alluvial fans on the western margins of the rift. The thickness of the Quaternary sedimentary fill is more than 465 m, with clastic sediments intercalated with basaltic lavas. The Quaternary alkali basaltic volcanism accompanied fluvial to lacustrine sedimentation between 1.57 ± 0.08 and 0.05 ± 0.03 Ma. The faults are left-lateral oblique-slip faults as indicated by left-stepping faulting patterns, slip-lineation data and left-laterally offset lava flows and stream channels along the Karasu fault zone. At Hacılar village, an offset lava flow, dated to 0.08 ± 0.06 Ma, indicates a rate of left-lateral oblique slip of approximately 4.1 mm·year–1. Overall, the Karasu Rift is an asymmetrical transtensional basin, which has developed between seismically active splays of the left-lateral DST and the left-lateral oblique-slip Karasu fault zone during the neotectonic period. 相似文献
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班公湖-怒江结合带北侧陆缘火山-岩浆弧带的厘定及其意义 总被引：9，自引：1，他引：9
在班公湖-怒江结合带西段北侧的拉热拉新岩体东、西两侧，新发现了一些早白垩世岩体、相伴的陆缘火山岩组合和矿(化)点，侵入岩和火山岩的岩石化学特征均显示其成因与中特提斯洋向北俯冲消减密切相关。本文将班-怒带北侧的火山-侵入岩带厘定为五峰尖-拉热拉新晚侏罗世-早白垩世陆缘火山-岩浆弧带，同时讨论了陆缘火山-岩浆弧带的厘定在分析中特提斯构造演化方面的研究意义。 相似文献
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在班公湖-怒江结合带西段北侧的拉热拉新岩体东、西两侧,新发现了一些早白垩世岩体、相伴的陆缘火山岩组合和矿(化)点,侵入岩和火山岩的岩石化学特征均显示其成因与中特提斯洋向北俯冲消减密切相关。本文将班- 怒带北侧的火山- 侵入岩带厘定为五峰尖拉热拉新晚侏罗世—早白垩世陆缘火山岩浆弧带,同时讨论了陆缘火山- 岩浆弧带的厘定在分析中特提斯构造演化方面的研究意义。 相似文献
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本文以荒沟山金矿为例,提出了利用黄铁矿氧化程度划分微细粒浸染型金矿床原生带和氧化带的准则。在荒沟山金矿研究中,利用这种方法将矿体划分为氧化带、混合带和原生眯矿床预测提供了依据。 相似文献
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Abigail L. Langston Gregory E. Tucker Robert S. Anderson Suzanne P. Anderson 《Applied Geochemistry》2011
Understanding the relationship between subsurface flow paths on hillslopes and chemical weathering of bedrock is fundamental to understanding the timing and mechanisms that weather bedrock to saprolite. The link between chemical weathering of bedrock and contact time with reactive water along flow paths motivates this study. Water drives the chemical alteration of rock into saprolite, yet connected porosity generally declines with depth into the weathered profile. Saprolite formation, therefore, reflects coupled weathering and permeability development over time. This study uses numerical modeling and soil-moisture monitoring to explore the hydrology of the unsaturated zone and the influence of fracture density, hillslope gradient, and permeability contrasts within the saprolite development horizon on saprolite development. 相似文献
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Structure and seismicity of the Aegean subduction zone 总被引：1，自引：0，他引：1
Tomographic results show the presence of a high-velocity anomaly dipping north beneath the Aegean Sea (Hellenic arc), down to a depth of at least 600 km. This anomaly is interpreted as the image of the subducting lithosphere of the African plate. No deep seismicity, however, is associated with this downgoing slab, although this would be expected on the basis of the age of the downbending lithosphere (approximately 100 Myr) and the inferred duration of the present ongoing episode of subduction. Using a thermo-mechanical model for the subduction zone we find that the non-stationary input of the subduction zone-both in convergence rate and in thermal structure of the downgoing lithosphere - adequately accounts for both the presence of a velocity anomaly associated with a slab and the absence of deep seismicity. The non-stationarity follows from the large-scale tectonic setting of the Eastern Mediterranean basin. 相似文献
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俯冲带作为联系地表和地球深部系统的纽带,不仅是将地表碳带入地球深部的主要通道,也是地表物质和地球深部物质发生交换的重要场所。俯冲作用可以将地表碳以有机碳或无机碳酸盐矿物等形式带入地球深部,再通过火山作用或去气作用返回到地表系统。俯冲带深部碳循环控制着地表碳通量变化,对于研究全球气候变化和地球宜居环境具有重要意义。本文结合前人的相关研究成果,综合探讨了俯冲带的脱碳机制及固碳作用过程。俯冲带脱碳机制主要有变质反应脱碳、流体溶解脱碳和熔融作用脱碳。从俯冲板块释放的含碳流体不一定都会迁移返回地表,有一部分含碳流体在迁移演化过程中会和围岩发生反应,形成不易迁移的其他含碳相(碳酸盐、石墨或金刚石)而重新固存在俯冲板块以及上覆地幔楔中(固碳作用),进而影响碳在不同储库中的含量变化,在计算俯冲带释放碳通量时需要考虑这一过程的影响。 相似文献
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2008年汶川地震促使人们思考青藏高原东南缘走向和规模与龙门山断裂带相近的丽江- 小金河断裂的活动历史,但受限于地质条件制约断裂尤其是其北段相关研究极其薄弱。基岩断裂带的物质组成与结构特征是断层长期活动的产物,蕴含丰富的历史活动信息。本文以丽江- 小金河断裂盐源段多个天然剖面为研究对象,通过详细的断裂带宏观结构调查、断层岩显微构造及XRD分析发现：① 断层破碎带以一套厚度>20 m的破裂面密集带为特征,优势破裂面走向为NE20°~30°,推测为丽江- 小金河断裂长期活动形成的张剪性破裂;② 断层带核部以断层角砾岩和断层泥为主,灰岩角砾岩黏土矿物含量~2%,以伊利石和伊蒙混层为主,粉砂岩断层泥黏土矿物含量~52%,以坡缕石和绿泥石为主,石英含量36%,缺失长石类矿物。断裂带宏观结构和断层岩微观结构特征均表现为角砾呈棱角状,砾径差异极大且呈零散状分布,符合快速滑动特征,指示断层滑移方式为黏滑。此外,核部断层岩带统计厚5~8 m,这一规模相对于龙门山映秀- 北川断裂带核部180~280 m和安县- 灌县断裂带核部40~50 m显著偏小,表明前者自形成以来的活动性远低于后者,两者的地震行为并不能简单类比。结合断裂在宏观结构特征、断层岩成分与种类以及所反映的滑动方式与隆升剥蚀量的差异,认为丽江- 小金河断裂更可能是鲜水河断裂切断锦屏山- 龙门山构造带之后形成的,晚新生代与龙门山断裂带具有不同的活动历史。 相似文献
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层间氧化带中褪色带的成因及其找矿意义 总被引：9，自引：0，他引：9
本文列举了国内外层间氧化带砂岩型铀矿床中的一些褪色现象 ,从宏观到微观地分析了褪色带的成因 ,认为褪色带的形成是在层间氧化带形成后 ,由深部上升的还原性气体或油气对氧化砂体进行还原的产物。运用国内外典型的事例说明主要工业铀矿体产于褪色带与原生带之间 ,由于褪色带是次生还原的产物 ,往往会将褪色带误认为是原生带 ,从而导致主要工业铀矿体漏失。由此分析推断出 :乌库尔其地区西部的 2 5 3线一带和中部的 3 89～ 42 1线一带第Ⅴ旋回铀矿体可能还在沿倾向向前延伸 ,目前已揭露的铀晕带是褪色带而不是还原带 ,这些地段的铀矿找矿工作应重新认识评价。 相似文献
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It is shown that a hypothetical relict magnetic field in the solar radiative-transport zone that penetrates into the convective
zone would affect the solar dynamo, resulting in radical changes in the butterfly diagrams. This would transform the traveling
waves of activity into standing waves. A comparison of our results with the well-known butterfly diagrams for the Sun gives
an upper limit of the order of some tens G for the value of relict magnetic field penetrating into the solar convective zone.
At the same time, it is not ruled out that such relict magnetic fields in other solar-type stars are strong enough to make
the activity waves become standing waves. 相似文献
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在拉轨岗日构造带佩枯错新发现了一条韧性剪切带,至少存在3期变形。韧性剪切作用可能与应变能转化的热能有关,应变能常沿断裂集中,形成方解石脉;然后,经由北往南的逆冲推覆,形成(叠瓦状)逆冲推覆构造;最后,由于山体重力势能的作用,伸展跨塌。该剪切带成为藏南拆离系的组成部分。 相似文献
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在拉轨岗日构造带佩枯错新发现了一条韧性剪切带，至少存在3期变形。韧性剪切作用可能与应变能转化的热能有关，应变能常沿断裂集中，形成方解石脉；然后，经由北往南的逆冲推覆，形成(叠瓦状)逆冲推覆构造；最后，由于山体重力势能的作用，伸展跨塌。该剪切带成为藏南拆离系的组成部分。 相似文献
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The difference in pressure condition of progressive metamorphism established by Schreinemakers' analysis of mineral assemblages in metabasalts makes it possible for the low grade metamorphism of the Izu-Tanzawa-Fujigawadani collision zone to be divided into three types. Type I is characterized by prehnite + epidote + hematite, suggesting the lowest pressure type; whereas type II is defined by prehnite + epidote + actinolite—the intermediate pressure type, and finally the distinctive assemblage of type III is pumpellyite + epidote + actinolite—the higher pressure type. The pressure conditions estimated are about 1 kbar for type I, 1–2 kbar for type II and 2–3 kbar for type III. The metamorphic rocks of type III occur in the southwestern part of the Tanzawa Mountains, and the metamorphic rocks of type I occur in the central Izu Peninsula and the northeast Tanzawa Mountains. Therefore, the upward displacement of the accretion mass due to collision deformation is most significant at the southwest Tanzawa Mountains. This suggests that the accretion of the Tanzawa and Izu blocks is accompanied with large-scale tilting of the mass. 相似文献
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S.I. Sherman 《Tectonophysics》1978,45(1):31-39
Baikal rift-zone faults range in magnitude from major through regional to local. The major, transcrustal faults of pre-Cenozoic initiation frame the structural pattern of the rift zone. Rifting causes a rejuvenation of all important faults regardless of their original type, many becoming oblique-slip faults. The displacement directions correlate well with the strike of the faults in terms of a single strain field for the region. Amplitudes of vertical and horizontal displacements are discussed. The general directions of the main crustal stresses are shown on a schematic diagram which illustrates the origin of different morphogenic groups of faults, and the main stages of their evolution. 相似文献
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V.P. Solonenko 《Tectonophysics》1978,45(1):61-69
High seismicity in the Baikal rift zone is controlled by the development of conjugate rising and subsiding block structures. Many types of seismological phenomena resulting from large earthquakes are manifested in the rift zone and include seismotectonic (regional, zonal and local), gravity-seismotectonic and seismogravitational deformations. Impulsive as distinct from gradual seismogenetic crustal movements play a dominant role in the recent development of the Baikal geomorphology. 相似文献
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郯庐断裂带的平移运动与成因 总被引：61，自引：4，他引：61
在华北、华南板块碰撞期间，郯庐断裂带究竟是何种边界仍是没有解决的重大地学问题，许多学者对此提出了不同的构造解释模式。关于郯庐断裂的平移距离仍存在着较大的分歧与有待深入研究之处。在华北、华南板块拼合之后，郯庐断裂带发生了一次大规模的左行平移，其糜棱岩的^40Ar／^39Ar年龄为132～119Ma，指示为早白垩世的平移活动，平移活动中伴生了强烈的岩浆活动。这期左行平移标志着中国东部构造的重大转折，是滨太平洋构造对前期古特提斯构造的叠加，其动力学机制为太平洋区伊侨奈岐板块突然出现的高速斜向俯冲。 相似文献