吉林舒兰断裂带的基本特征          下载免费PDF全文

刘祥 《地震地质》1988,10(3):28

舒兰断裂带是东北地区著名的依兰—伊通断裂带的中段。本文从构造分析和历史发展的角度出发,阐述了舒兰断裂带的基本特征及其晚近时期新活动  相似文献   

Tectonic geomorphology of the Mississippi Valley between Osceola, Arkansas and Friars Point, Mississippi   总被引：1，自引：0，他引：1  

W.J. Spitz  S.A. Schumm 《Engineering Geology》1997,46(3-4):259-280

A geomorphic study of the Mississippi River and its alluvial valley between Osceola, Arkansas and Friars Point, Mississippi has identified anomalous surface features that can be linked to known geological structures. For example, relatively recent deformation along Big Creek fault zone, White River fault zone, Bolivar-Mansfield tectonic zone, Blytheville Arch, Crittenden County fault zone, and Reelfoot Rift margins is suggested by river and topographic anomalies. Faults and plutons appear to affect drainage networks, and the morphology of Crowleys Ridge suggests significant fault control. The many anomalies probably reflect a fractured suballuvial surface. Although movement along these fractures will most likely occur in seismically active areas, the probability of movement elsewhere  相似文献   

湘鄂赣皖交界区的湖盆演化及其控制因素   总被引：11，自引：1，他引：11  

吴在耀 《大地构造与成矿学》1997,21(3):251-261

受燕山期构造格局控制，湘鄂赣皖交界区的白垩-早第三纪湖盆呈近东西向和近南北向展布、第四纪湖盆继承这一格局发育，局部受到新构造运动改造，其中最重要的是北北东向的江汉-洞庭断陷；麻城-团风断裂控制了孝感断陷和梁子湖断陷，并使某些断陷湖演化为复成因湖。北西向断裂和鄂东南的掀斜对第四纪湖盆发育也有重要作用。在此基础上讨论了燕山运动的特征、北北东向断裂新生代活动的机制等问题。  相似文献   

对庐山东麓第四纪沉积物物源及新构造运动的新认识   总被引：19，自引：1，他引：19  

朱诚 《地理学报》1995,50(1):41-50,T002

根据在庐山山上和庐山东麓采集的基岩和沉积物砾石标本薄片鉴定，发现山上基岩和山麓沉积物在岩性之间没有必然的联系。山麓大多数沉积物在岩性和沉积相上类似于白砂井组，作者认为该沉积物主要是古赣江上游搬运来的物质。论证了网纹红土主要是中更新世初湿热低平地形下形成，而庐山现今１０００－１２００ｍ高度存在着变位网纹红土，由此推论，庐山在网纹红土形成后（中更新世中期以来）的新构造运动中，山体抬升了约６００－８００  相似文献   

Structural development of the Tso Morari ultra-high pressure nappe of the Ladakh Himalaya   总被引：2，自引：0，他引：2  

Jean-Luc Epard  Albrecht Steck   《Tectonophysics》2008,451(1-4):242-264

A continental subduction-related and multistage exhumation process for the Tso Morari ultra-high pressure nappe is proposed. The model is constrained by published thermo-barometry and age data, combined with new geological and tectonic maps. Additionally, observations on the structural and metamorphic evolution of the Tso Morari area and the North Himalayan nappes are presented. The northern margin of the Indian continental crust was subducted to a depth of > 90 km below Asia after continental collision some 55 Ma ago. The underthrusting was accompanied by the detachment and accretion of Late Proterozoic to Early Eocene sediments, creating the North Himalayan accretionary wedge, in front of the active Asian margin and the 103–50 Ma Ladakh arc batholith. The basic dikes in the Ordovician Tso Morari granite were transformed to eclogites with crystallization of coesite, some 53 Ma ago at a depth of > 90 km (> 27 kbar) and temperatures of 500 to 600 °C. The detachment and extrusion of the low density Tso Morari nappe, composed of 70% of the Tso Morari granite and 30% of graywackes with some eclogitic dikes, occurred by ductile pure and simple shear deformation. It was pushed by buoyancy forces and by squeezing between the underthrusted Indian lithosphere and the Asian mantle wedge. The extruding Tso Morari nappe reached a depth of 35 km at the base of the North Himalayan accretionary wedge some 48 Ma ago. There the whole nappe stack recrystallized under amphibolite facies conditions of a Barrovian regional metamorphism with a metamorphic field gradient of 20 °C/km. An intense schistosity with a W–E oriented stretching lineation L₁ and top-to-the E shear criteria and crystallization of oriented sillimanite needles after kyanite, testify to the Tso Morari nappe extrusion and pressure drop. The whole nappe stack, comprising from the base to top the Tso Morari, Tetraogal, Karzok and Mata–Nyimaling-Tsarap nappes, was overprinted by new schistosities with a first N-directed and a second NE-directed stretching lineation L₂ and L₃ reaching the base of the North Himalayan accretionary wedge. They are characterized by top-to-the S and SW shear criteria. This structural overprint was related to an early N- and a younger NE-directed underthrusting of the Indian plate below Asia that was accompanied by anticlockwise rotation of India. The warping of the Tso Morari dome started already some 48 Ma ago with the formation of an extruding nappe at depth. The Tso Morari dome reached a depth of 15 km about 40 Ma ago in the eastern Kiagar La region and 30 Ma ago in the western Nuruchan region. The extrusion rate was of about 3 cm/yr between 53 and 48 Ma, followed by an uplift rate of 1.2 mm/yr between 48 and 30 Ma and of only 0.5 mm/yr after 30 Ma. Geomorphology observations show that the Tso Morari dome is still affected by faults, open regional dome, and basin and pull-apart structures, in a zone of active dextral transpression parallel to the Indus Suture zone.  相似文献   

The North Maladeta Fault (Spanish Central Pyrenees) as the Vielha 1923 earthquake seismic source: Recent activity revealed by geomorphological and geophysical research   总被引：2，自引：1，他引：1  

M. Ortuo  P. Queralt  A. Martí  J. Ledo  E. Masana  H. Perea  P. Santanach 《Tectonophysics》2008,453(1-4):246

The Spanish Central Pyrenees have been the scenario of at least two damaging earthquakes in the last 800 years. Analysis of macroseismic data of the most recent one, the Vielha earthquake (19 November 1923), has led to the identification of the North Maladeta Fault (NMF) as the seismic source of the event. This E–W trending fault defines the northern boundary of the Maladeta Batholith and corresponds to a segment of the Alpine Gavarnie thrust fault. Our study shows that the NMF offsets a reference Neogene peneplain. The maximum observed vertical displacement is  730 m, with the northern downthrown sector slightly tilting towards the South. This offset provides evidence of normal faulting and together with the presence of tectonic faceted spurs allowed us to geomorphically identify a fault trace of 17.5 km. This length suggests that a maximum earthquake of M_w = 6.5 ± 0.66 could occur in the area. The geomorphological study was improved with a resistivity model obtained at Prüedo, where a unique detritic Late Miocene sequence crops out adjacent to the NMF. The section is made up of 13 audiomagnetotelluric soundings along a 1.5 km transect perpendicular to the fault trace at Prüedo and reveals the structure in depth, allowing us to interpret the Late Miocene deposits as tectonically trapped basin deposits associated with normal faulting of the NMF. The indirect age of these deposits has been constrained between 11.1 and 8.7 Ma, which represents a minimum age for the elevated Pyrenean peneplain in this part of the Pyrenees. Therefore, we propose the maximum vertical dip-slip rate for the NMF to be between 0.06 and 0.08 mm/a. Normal faulting in this area is attributed to the vertical lithospheric stress associated with the thickened Pyrenean crust.  相似文献   

湟水河流域不对称地貌与青藏高原—祁连山隆升   总被引：6，自引：0，他引：6  

黄生长  李长安 《江西地质》1998,12(4):251-256

湟水河流域发育夷平面和不对称的分水岭、阶地、沟谷等地貌,不对称地貌主要有简单不对称沟谷、不对称分水岭和阶地式不对称沟谷。它们是由于南北两侧隆升幅度不同,在地面流水侵蚀作用下产生。地貌的不对称反映出青藏高原的隆升在大的时间尺度上是均匀的,在小尺度上是不均匀的;高原隆升到一定高度后,受印度板块侧向挤压、高原向四周扩展的应力的共同作用引起了祁连山的隆升;祁连山隆升的同时西北地区的气候开始恶化  相似文献   

Reconstructions of the Mediterranean Outflow Water during the quaternary based on the study of changes in buried mounded drift stacking pattern in the Gulf of Cadiz     

Estefania Llave  Francisco J. Hernández-Molina  Dorrik A. V. Stow  Mari Carmen Fernández-Puga  Margarita García  Juan T. Vázquez  Adolfo Maestro  Luis Somoza  Victor Díaz del Río 《Marine Geophysical Researches》2007,28(4):379-394

Contourite deposits in the central sector of the middle slope of the Gulf of Cadiz have been studied using a comprehensive acoustic, seismic and core database. Buried, mounded, elongated and separated drifts developed under the influence of the lower core of the Mediterranean Outflow Water are preserved in the sedimentary record. These are characterised by depositional features in an area where strong tectonic and erosive processes are now dominant. The general stacking pattern of the depositional system is mainly influenced by climatic changes through the Quaternary, whereas changes in the depositional style observed in two, buried, mounded drifts, the Guadalquivir and Huelva Drifts, are evidence of a tectonic control. In the western Guadalquivir Drift, the onset of the sheeted drift construction (aggrading QII unit) above a mounded drift (prograding QI unit) resulted from a new Lower Mediterranean Core Water hydrodynamic regime. This change is correlated with a tectonic event coeval with the Mid Pleistocene Revolution (MPR) discontinuity that produced new irregularities of the seafloor during the Mid- to Late-Pleistocene. Changes in the Huelva Drift from a mounded to a sheeted drift geometry during the Late-Pleistocene, and from a prograding drift (QI and most part of QII) to an aggrading one (upper seismic unit of QII), highlight a new change in oceanographic conditions. This depositional and then oceanographic change is associated with a tectonic event, coeval with the Marine Isotope Stage (MIS) 6 discontinuity, in which a redistribution of the diapiric ridges led to the development of new local gateways, three principal branches of the Mediterranean Lower Core Water, and associated contourite channels. As a result, these buried contourite drifts hold a key palaeoceanographic record of the evolution of Mediterranean Lower Core Water, influenced by both neotectonic activity and climatic changes during the Quaternary. This study is an example of how contourite deposits and erosive elements in the marine environment can provide evidence for the reconstruction of palaeoceanographic and recent tectonic changes.  相似文献   

Quantifying the slip rates, spatial distribution and evolution of active normal faults from geomorphic analysis: Field examples from an oblique-extensional graben, southern Turkey   总被引：1，自引：0，他引：1  

Sarah J. Boulton  Alexander C. Whittaker 《Geomorphology》2009,104(3-4):299-316

Quantifying the extent to which geomorphic features can be used to extract tectonic signals is a key challenge in the Earth Sciences. Here we analyse the drainage patterns, geomorphic impact, and long profiles of bedrock rivers that drain across and around normal faults in a regionally significant oblique-extensional graben (Hatay Graben) in southern Turkey that has been mapped geologically, but for which there are poor constraints on the activity, slip rates and Plio–Pleistocene evolution of basin-bounding faults. We show that drainage in the Hatay Graben is strongly asymmetric, and by mapping the distribution of wind gaps, we are able to evaluate how the drainage network has evolved through time. By comparing the presence, size, and distribution of long profile convexities, we demonstrate that the northern margin of the graben is tectonically quiescent, whereas the southern margin is bounded by active faults. Our analysis suggests that rivers crossing these latter faults are undergoing a transient response to ongoing tectonic uplift, and this interpretation is supported by classic signals of transience such as gorge formation and hill slope rejuvenation within the convex reach. Additionally, we show that the height of long profile convexities varies systematically along the strike of the southern margin faults, and we argue that this effect is best explained if fault linkage has led to an increase in slip rate on the faults through time from  0.1 to 0.45 mm/yr. By measuring the average length of the original fault segments, we estimate the slip rate enhancement along the faults, and thus calculate the range of times for which fault acceleration could have occurred, given geological estimates of fault throw. These values are compared with the times and slip rates required to grow the documented long-profile convexities enabling us to quantify both the present-day slip rate on the fault (0.45 ± 0.05 mm/yr) and the timing of fault acceleration (1.4 ± 0.2 Ma). Our results have substantial implications for predicting earthquake hazard in this densely populated area (calculated potential M_w = 6.0–6.6), enable us to constrain the tectonic evolution of the graben through time, and more widely, demonstrate that geomorphic analysis can be used as an effective tool for estimating fault slip rates over time periods > 10⁶ years, even in the absence of direct geodetic constraints.  相似文献   

Pie de Palo, Argentina: A cataclastic diapir     

Claudio Vita-Finzi   《Geomorphology》2009,104(3-4):317-322

The term cataclastic diapirism is proposed for the low-temperature extrusion of highly fractured rocks through more competent strata to produce domed topographies at the surface. The process is illustrated by reference to the geomorphology, neotectonics and microseismicity of the Pie de Palo, an elongated ridge in the western Sierras Pampeanas of Argentina composed of shattered and sheared Lower Palaeozoic rocks and subject to coseismic uplift. The Pie de Palo is conventionally interpreted as a fault-driven basement fold linked to low-angle eastward subduction of the Nazca plate beneath South America; the diapiric model implies instead that deformation is powered by regional compression from west-verging, near-surface, crustal shortening which results ultimately from Atlantic spreading.  相似文献