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1.
燕山东段～下辽河地区中新生代断裂演化与构造期次 总被引：5，自引：3，他引：2
通过对燕山东段～下辽河盆地中新生代断裂演化分析,认为中新生代该区共经历了中三叠世末,早侏罗世末,晚侏罗世末,白垩纪末和老第三纪末５期挤压作用。每期挤压作用都形成相应的挤压构造形迹,使得早期盆地萎缩或消亡,或对早期盆地进行改造使其反转。此外,该区还曾经历了中晚侏罗世,白垩纪和新生代３个明显的伸展作用阶段,形成中晚侏罗世断裂盆地,白垩纪断陷盆地和新生代裂谷盆地,构造演化过程中挤压作用和伸展作用交替出现 相似文献
2.
丽水-椒江凹陷是晚白垩世以来发展起来的大陆边缘裂陷盆地.本文利用平衡剖面技术恢复计算了丽水-椒江凹陷不同构造部位各裂陷伸展期的盆地伸展量、伸展系数和伸展率.研究表明:研究区晚白垩世至古新世裂陷作用具有"幕式"渐进发展的特征,可划分为三个裂陷伸展期:早期(晚白垩世)的断陷主要由相对分散、独立的小断陷组成,控制半地堑凹陷的主断层主要以书斜式(domino-style)为主;中、晚期(古新世)的断陷由相互连通的半地堑凹陷组成,其主干断层以犁状(listric)或坡坪状(ramp-flat)正断层为特征.研究区不同构造部位其水平伸展率不同,表现为水平伸展量由南西向北东由大变小的特征,最大伸展期亦表现为由南西向北东变晚的规律. 相似文献
3.
燕山东段下辽河地区中新生代盆山构造演化 总被引：9，自引：1，他引：8
笔者通过分析燕山东段-下辽河地区的前中生代构造背景和中新生代盆山构造演化认为,该区中新生代的构造演化过程是在前中生代华北克拉通岩石图基础上发育起来的克拉通内(陆内或板内)盆山构造与挤压构造的交替演化过程,经历了早-中三叠世、晚三叠世-早侏罗世、中-晚侏罗世、白垩纪、新生代5个盆山构造演化阶段和中三叠世末、早侏罗世末、晚侏罗世末和白垩纪末、老第三纪末5期挤压作用。每次挤压作用都使得早期盆地萎缩或消亡,造成早期盆地反转。中-晚侏罗世、白垩纪和新生代三个阶段的伸展作用形成中-晚侏罗世断陷盆地、白垩纪断陷盆地和新生代裂谷盆地。在这一构造演化过程中,挤压作用和伸展作用交替出现,挤压构造和伸展构造间互发育。 相似文献
4.
华北北部中新生代构造体制的转换过程 总被引：15，自引：0，他引：15
华北北部位于古亚洲和太平洋两大全球性构造域的交叠部位,其中新生代断裂演化、区域性不整合界面和盆地演化的地质事实显示华北北部中新生代存在5个挤压作用时期。自老至新为:①中三叠世末挤压期(老虎沟组或杏石口组前挤压期,峰值年龄 ≥ 215Ma);②早侏罗世末挤压期(海房沟组或九龙山组前挤压期,峰值年龄 ≥ 178Ma);③晚侏罗世末挤压期(义县组或东岭台组前挤压期,峰值年龄 ≥ 135Ma);④晚白垩世末挤压期(古近系前挤压期,峰值年龄65Ma);⑤古近纪末挤压期(新近纪前挤压期,峰值年龄25Ma).5个挤压期在时间上相对较短,并为6个时间较长,构造运动相对和缓或伸展的成盆沉积期一一隔开。6个成盆沉积期包括:早中三叠世、晚三叠世-早侏罗世、中晚侏罗世、白垩纪、古近纪、新近纪-第四纪。其中,中晚侏罗世、白垩纪、古近纪、新近纪-第四纪具有明显的伸展作用特征。也就是说,华北北部中新生代的构造演化过程是在前中生代华北克拉通岩石圈基础上发育起来的克拉通内(陆内或板内)成盆沉积与挤压变形的交替演化过程,在这一构造演化过程中,挤压作用和伸展作用均占有重要位置,总体来讲,挤压作用由强变弱,伸展作用由弱变强。伸展作用持续的时间长,挤压作用持续时间则相对较短。挤压作用和伸展作用交替出现,挤压构造和伸展构造间互发育。华北北部中新生代这种构造体制的转换过程,记录了从古亚洲洋构造域汇聚构造体制向太平洋构造域俯冲构造体制转换的大陆动力学过程。 相似文献
5.
L.S. Shu X.M. Zhou P. Deng B. Wang S.Y. Jiang J.H. Yu X.X. Zhao 《Journal of Asian Earth Sciences》2009,34(3):376-391
In order to better understand the Mesozoic tectonic evolution of Southeast China Block (SECB in short), this paper describes geological features of Mesozoic basins that are widely distributed in the SECB. The analyzed data are derived from a regional geological investigation on various Mesozoic basins and a recently compiled 1:1,500,000 geological map of Mesozoic–Cenozoic basins. Two types of basin are distinguished according to their tectonic settings, namely, the post-orogenic basin (Type I) and the intracontinental extensional basin (Type II); the latter includes the graben and the half-graben or faulted-depression basins. Our studies suggest that the formation of these basins connects with the evolution of geotectonics of the SECB. The post-orogenic basin (Type I) was formed in areas from the piedmont to the intraland during the interval from Late Triassic to Early Jurassic; and the formation of the intracontinental extensional basin (Type II) connects with an intracontinental crustal thinning setting in the Late Mesozoic. The graben basin was generated during the Middle Jurassic and is associated with a bimodal volcanic eruption; and the half-graben or faulted-depression basin, filled mainly by the rhyolite, tuff and sedimentary rocks during Early Cretaceous, is occupied by the Late Cretaceous–Paleogene red-colored terrestrial clastic rocks. We noticed that the modern outcrops of numerous granites and basins occur in a similar level, and the Mesozoic granitic bodies contact with the adjacent basins by large normal faults, suggesting that the modern landforms between granites and basins were yielded by the late crustal movement. The modern basin and range framework was settled down in the Cretaceous. Abundant sedimentary structures are found in the various basins, from that the deposited environments and paleo-currents are concluded; during the Late Triassic–Early Jurassic time, the source areas were situated to the north and northeast sides of the outcrop region. In this paper, we present the study results on one geological and geographical separating unit and two separating fault zones. The Wuyi orogenic belt is a Late Mesozoic paleo-geographically separating unit, the Ganjiang fault zone behaves as the western boundary of Early Cretaceous volcanic rocks, and the Zhenghe–Dapu fault zone separates the SE-China Coastal Late Mesozoic volcanic-sedimentary basins and the Wuyi orogenic belt. Finally, we discuss the geodynamic mechanisms forming various basins, proposing a three-stage model of the Mesozoic sedimentary evolution. 相似文献
6.
胶莱盆地及其邻区白垩纪－古新世沉积构造演化历史及其区域动力学意义 总被引：15，自引：2，他引：13
基于野外和钻孔测井资料分析、火山岩同位素年代学分析 (40Ar-39Ar and SHRIMP U-Pb)、地震剖面的构造解释、断层运动学的野外分析结果,综合研究了胶莱盆地及其邻区白垩纪－古新世沉积构造演化历史。岩性地层分析表明,胶莱断陷盆地由三套地层单元所充填：早白垩世莱阳群和青山群、晚白垩世－古新世王氏群。青山群火山岩的同位素年代学测试结果给出了该火山岩的喷发时代在120～105 Ma。地震剖面的构造解译结果揭示胶莱盆地伸展构造受到深部两个拆离构造系统控制：一个发育于盆地南部地区,拆离断面位于深部8~10 km,向南缓倾于苏鲁造山带之下;另一个拆离系统由一系列北倾的犁式断层组成、分布于宽阔的胶莱盆地北部地区,主拆离面向北倾。这两个拆离系统分别形成于早白垩世莱阳群和晚白垩世-古新世王氏群沉积阶段。通过对不同地层单元断层滑动矢量的野外测量和古构造应力场反演,以及地层时代和同位素年代学测试结果的制约,建立了白垩纪－古新世构造应力场演替的年代序列。结果表明,胶莱盆地在白垩纪-古新世之间经历了伸展－挤压应力体制的交替演化。早白垩世伸展作用经历了两个不同的阶段：早期NW-SE向伸展和晚期近W-E向伸展。在早白垩世末期至晚白垩世初期,盆地遭受NW-SE向挤压,导致了胶莱盆地的缩短变形和郯庐断裂带的左旋走滑活动。晚白垩世－古新世时期,构造应力场转变为N-S向伸展,直到古新世末期,构造应力场转换为NE－SW向挤压。胶莱盆地和沂沭裂谷系白垩纪－古新世沉积构造演化历史对华北地区岩石圈减薄过程的动力学背景提供了重要的构造地质学制约。笔者推断,早白垩世两期引张应力作用是分别对华北地区增厚地壳或岩石圈的重力垮塌和岩石圈拆沉的响应,而早白垩世末期NW-SE向挤压记录了古太平洋板块与亚洲陆缘俯冲碰撞产生的远程效应。晚白垩世-古新世的引张伸展作用完全不同于早白垩世伸展构造,它指示了沿NNE向郯庐断裂带的右旋走滑活动及其拉分作用,在动力学上受到青藏地区块体的陆－陆碰撞产生的远程效应和古太平洋板块向亚洲大陆俯冲作用的联合应力场控制。 相似文献
7.
SHU Liangshu ZHOU Xinmin DENG Ping ZHU Wenbin 《《地质学报》英文版》2007,81(4):573-586
The Late Triassic to Paleogene(T_3-E) basin occupies an area of 143100 km~2,being the sixth area of the whole of SE China;the total area of synchronous granitoid is about 127300 km~2;it provides a key for understanding the tectonic evolution of South China.From a new 1:1500000 geological map of the Mesozoic-Cenozoic basins of SE China,combined with analysis of geometrical and petrological features,some new insights of basin tectonics are obtained.Advances include petrotectonic assemblages, basin classification of geodynamics,geometric features,relations of basin and range.According to basin-forming geodynamicai mechanisms,the Mesozoic-Cenozoic basin of SE China can be divided into three types,namely:1) para-foreland basin formed from Late Triassic to Early Jurassic(T_3-J_1) under compressional conditions;2) rift basins formed during the Middle Jurassic(J_2) under a strongly extensional setting;and 3) a faulted depression formed during Early Cretaceous to Paleogene (K_1-E) under back-arc extension action.From the rock assemblages of the basin,the faulted depression can be subdivided into a volcanic-sedimentary type formed mainly during the Early Cretaceous(K_1) and a red -bed type formed from Late Cretaceous to Paleogene(K_2-E).Statistical data suggest that the area of all para-foreland basins(T_3-J_1) is 15120 km~2,one of rift basins(J_2) occupies 4640 km~2,and all faulted depressions equal to 124330 km~2 including the K_2-E red-bed basins of 37850 km~2.The Early Mesozoic (T_3-J_1) basin and granite were mostly co-generated under a post-collision compression background, while the basins from Middle Jurassic to Paleogene(J_2-E) were mainly constrained by regional extensional tectonics.Three geological and geographical zones were surveyed,namely:1)the Wuyishan separating zone of paleogeography and climate from Middle Jurassic to Tertiary;2)the Middle Jurassic rift zone;and 3)the Ganjiang separating zone of Late Mesozoic volcanism.Three types of basin-granite relationships have been identified,including compressional(a few),strike-slip(a few), and extensional(common).A three-stage geodynamical evolution of the SE-China basin is mooted:an Early Mesozoic basin-granite framework;a transitional Middle Jurassic tectonic regime; intracontinental extension and red-bed faulted depressions since the Late Cretaceous. 相似文献
8.
大杨树盆地的构造特征及变形期次 总被引：4，自引：0，他引：4
大杨树盆地是叠置于大兴安岭造山带的东部,与松辽盆地紧邻,呈北北东向长条带状展布的中新生代断陷-坳陷型盆地。大杨树盆地经历了多期变形作用,具有以伸展构造为主、并被挤压构造和反转构造叠加的构造特征。早白垩世龙江期主要受到了NWW—SEE向的拉伸作用,形成一系列北北东向控陷犁式正断层组合,在控陷断层的上盘发育小型箕状断陷;早白垩世九峰山期,大杨树盆地受挤压作用控制,使早期形成的断陷盆地发生反转作用,形成正反转构造,同时在某些地段形成逆冲断层和断层传播褶皱;早白垩世甘河期,大杨树盆地再次受到伸展作用,形成了一系列北北东向小型断陷。早白垩世晚期(甘河期之后)—晚白垩世早期,大杨树盆地受到强烈的挤压作用,使早期控陷正断层出现正反转作用,在盆地的浅部形成大型断层传播褶皱,使大杨树盆地全面隆升遭受剥蚀。第四纪大杨树盆地具有伸展的特征,发育一系列小型伸展断陷。 相似文献
9.
The southern Central Andes of Argentina and Chile (27–40°S) are the product of deformation, arc magmatism, and basin evolution above a long-lived subduction system. With sufficient timing and provenance constraints, Andean stratigraphic and structural records enable delineation of Mesozoic-Cenozoic variations in subsidence and tectonic regime. For the La Ramada Basin in the High Andes at ∼31–33°S, new assessments of provenance and depositional age provided by detrital zircon U-Pb geochronology help resolve deformational patterns and subsidence mechanisms over the past ∼200 Myr. Marine and nonmarine clastic deposits recorded the unroofing of basin margins and sediment contributions from the Andean magmatic arc during Late Triassic to Early Cretaceous extension, thermal subsidence, and possible slab rollback. Subsequent sediment delivery from the Coastal Cordillera corresponded with initial flexural accommodation in the La Ramada Basin during Andean shortening of late Early Cretaceous to Late Cretaceous age. The architecture of the foreland basin was influenced by the distribution of precursor extensional depocenters, suggesting that inherited basin geometries provided important controls on later flexural subsidence and basin evolution. Following latest Cretaceous to early Paleogene tectonic quiescence and a depositional hiatus, newly dated deposits in the western La Ramada Basin provide evidence for a late Paleogene episode of intra-arc and proximal retroarc extension (development of the Abanico Basin, principally in Chile, at ∼28–44°S). Inversion of this late Paleogene extensional basin system during Neogene compression indicates the southern Central Andes were produced by at least two punctuated episodes of shortening and uplift of Late Cretaceous and Neogene age. 相似文献
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楚雄盆地处于中国云南省中部，位于扬子板块西南缘，南西界以红河断裂为界与哀牢山造山带相连，北西界为程海断裂，东边为绿汁江断裂。盆地基底包括结晶基底和褶皱基底双重结构。盆地内发育了中三叠世以后的沉积盖层，西部中三叠世和晚三叠世早、中期为海相沉积，晚期为海陆交互相和陆相沉积；盆地东部为陆相沉积。侏罗—白垩纪整个盆地为巨厚的陆相沉积。楚雄盆地的构造格架分为４个带：（１）哀牢山造山带；（２）褶皱逆冲带；（３）中部沉降带；（４）东部隆起带。盆地形成与演化分为六个阶段：（１）被动大陆边缘沉降阶段；（２）拉张热隆起边缘——裂谷盆地阶段；（３）沟－弧－盆系阶段；（４）残洋－周缘前陆盆地阶段；（５）走滑－拉张盆地阶段；（６）走滑－挤压－改造阶段。楚雄盆地的形成与演化体现了盆地动力学性质转化和复合，在多种动力系统作用下或经过多旋回构造阶段产生了复式盆地 相似文献
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The Schlinig fault at the western border of theÖtztal nappe (Eastern Alps), previously interpreted as a west-directed thrust, actually represents a Late Cretaceous, top-SE to -ESE normal fault, as indicated by sense-of-shear criteria found within cataclasites and greenschist-facies mylonites. Normal faulting postdated and offset an earlier, Cretaceous-age, west-directed thrust at the base of theÖtztal nappe. Shape fabric and crystallographic preferred orientation in completely recrystallized quartz layers in a mylonite from the Schlinig fault record a combination of (1) top-east-southeast simple shear during Late Cretaceous normal faulting, and (2) later north-northeast-directed shortening during the Early Tertiary, also recorded by open folds on the outcrop and map scale. Offset of the basal thrust of theÖtztal nappe across the Schlinig fault indicates a normal displacement of 17 km. The fault was initiated with a dip angle of 10° to 15° (low-angle normal fault). Domino-style extension of the competent Late Triassic Hauptdolomit in the footwall was kinematically linked to normal faulting.
The Schlinig fault belongs to a system of east- to southeast-dipping normal faults which accommodated severe stretching of the Alpine orogen during the Late Cretaceous. The slip direction of extensional faults often parallels the direction of earlier thrusting (top-W to top-NW), only the slip sense is reversed and the normal faults are slightly steeper than the thrusts. In the western Austroalpine nappes, extension started at about 80 Ma and was coeval with subduction of Piemont-Ligurian oceanic lithosphere and continental fragments farther west. The extensional episode led to the formation of Austroalpine Gosau basins with fluviatile to deep-marine sediments. West-directed rollback of an east-dipping Piemont-Ligurian subduction zone is proposed to have caused this stretching in the upper plate. 相似文献
14.
合肥盆地的沉积作用与其东缘的郯庐断裂带演化有着良好的耦合关系。侏罗纪盆地发育主要受大别造山带演化控制,东部可见对同造山期郯庐断裂带左旋转换走滑的沉积响应。盆地内朱巷组的沉积是对早白垩世早期郯庐断裂再次发生陆内左行平移的响应,该时期成盆模式为一走滑—挠曲盆地。盆地内上白垩统—古近系的形成是对这期间郯庐断裂带伸展活动的响应,盆地具区域性伸展(双向伸展)的特征。盆地东部自新近纪以来的抬升、消亡与东缘反转构造的存在,指示了郯庐断裂带的逆冲活动。盆地东部的沉积记录结合近年来郯庐断裂带内部构造与同位素年代学的最新研究成果,指示该断裂带中-新生代经历了4个演化阶段:同造山期的左旋转换走滑、早白垩世早期的陆内左行平移、晚白垩世—古近纪的伸展运动和新近纪以来的逆冲活动。 相似文献
15.
The study provides a regional seismic interpretation and mapping of the Mesozoic and Cenozoic succession of the Lusitanian Basin and the shelf and slope area off Portugal. The seismic study is compared with previous studies of the Lusitanian Basin. From the Late Triassic to the Cretaceous the study area experienced four rift phases and intermittent periods of tectonic quiescence. The Triassic rifting was concentrated in the central part of the Lusitanian Basin and in the southernmost part of the study area, both as symmetrical grabens and half-grabens. The evolution of half-grabens was particularly prominent in the south. The Triassic fault-controlled subsidence ceased during the latest Late Triassic and was succeeded by regional subsidence during the early Early Jurassic (Hettangian) when deposition of evaporites took place. A second rift phase was initiated in the Early Jurassic, most likely during the Sinemurian–Pliensbachian. This resulted in minor salt movements along the most prominent faults. The second phase was concentrated to the area south of the Nazare Fault Zone and resulted here in the accumulation of a thick Sinemurian–Callovian succession. Following a major hiatus, probably as a result of the opening of the Central Atlantic, resumed deposition occurred during the Late Jurassic. Evidence for Late Jurassic fault-controlled subsidence is widespread over the whole basin. The pattern of Late Jurassic subsidence appears to change across the Nazare Fault Zone. North of the Nazare Fault, fault-controlled subsidence occurred mainly along NNW–SSE-trending faults and to the south of this fault zone a NNE–SSW fault pattern seems to dominate. The Oxfordian rift phase is testified in onlapping of the Oxfordian succession on salt pillows which formed in association with fault activity. The fourth and final rift phase was in the latest Late Jurassic or earliest Early Cretaceous. The Jurassic extensional tectonism resulted in triggering of salt movement and the development of salt structures along fault zones. However, only salt pillow development can be demonstrated. The extensional tectonics ceased during the Early Cretaceous. During most of the Cretaceous, regional subsidence occurred, resulting in the deposition of a uniform Lower and Upper Cretaceous succession. Marked inversion of former normal faults, particularly along NE–SW-trending faults, and development of salt diapirs occurred during the Middle Miocene, probably followed by tectonic pulses during the Late Miocene to present. The inversion was most prominent in the central and southern parts of the study area. In between these two areas affected by structural inversion, fault-controlled subsidence resulted in the formation of the Cenozoic Lower Tagus Basin. Northwest of the Nazare Fault Zone the effect of the compressional tectonic regime quickly dies out and extensional tectonic environment seems to have prevailed. The Miocene compressional stress was mainly oriented NW–SE shifting to more N–S in the southern part. 相似文献
16.
A. P. Gartrell 《Australian Journal of Earth Sciences》2013,60(2):231-244
The extensional architecture of the Northern Carnarvon Basin can be explained in terms of changes in lithospheric rheology during multiphase extension and lower crustal flow. Low‐angle detachments, while playing a minor role, are not considered to have been the primary mechanism for extension as suggested in previous models. Early extension (Cambrian‐Ordovician) in the Northern Carnarvon Basin is characterised by low‐angle detachment structures of limited regional extent. These structures have a spatial association with a Proterozoic mobile belt on the margin of the Pilbara Craton. Thermo‐mechanical conditions in the mobile belt may have predisposed the highly deformed crust to thin‐skinned extension and detachment development. Permo‐Carboniferous extension generated an extensive wide rift basin, suggesting ductile rheologies associated with intermediate lithospheric temperatures and crustal thickness. Thick Upper Permian to Upper Triassic post‐rift sequences and marked thinning of the lower crust occurred in association with only a small amount of extension in the upper crust. This observation can be reconciled by considering outward lower crustal flow, from beneath the basin towards the basin margin, following extension. Strong mid‐crustal reflectors, which occur over large areas of the Northern Carnarvon Basin, probably represent a boundary between flow and non‐flow regimes rather than detachment fault surfaces as in previous models. Crustal thinning and thermal decay following Permo‐Carboniferous extension contributed to the increased strength and brittle behaviour of the lithosphere. Consequently, Late Triassic to Early Cretaceous extension resulted in the development of far more localised narrow rift systems on the margins of the preceding wide rift basin. Diapiric intrusions are associated with the narrow rift basin development, resulting from either remobilisation of ductile lower crustal rock or the initial formation of sea‐floor spreading centres. 相似文献
17.
L.F. Sarmiento-Rojas J.D. Van Wess S. Cloetingh 《Journal of South American Earth Sciences》2006,21(4):383
Backstripping analysis and forward modeling of 162 stratigraphic columns and wells of the Eastern Cordillera (EC), Llanos, and Magdalena Valley shows the Mesozoic Colombian Basin is marked by five lithosphere stretching pulses. Three stretching events are suggested during the Triassic–Jurassic, but additional biostratigraphical data are needed to identify them precisely. The spatial distribution of lithosphere stretching values suggests that small, narrow (<150 km), asymmetric graben basins were located on opposite sides of the paleo-Magdalena–La Salina fault system, which probably was active as a master transtensional or strike-slip fault system. Paleomagnetic data suggesting a significant (at least 10°) northward translation of terranes west of the Bucaramanga fault during the Early Jurassic, and the similarity between the early Mesozoic stratigraphy and tectonic setting of the Payandé terrane with the Late Permian transtensional rift of the Eastern Cordillera of Peru and Bolivia indicate that the areas were adjacent in early Mesozoic times. New geochronological, petrological, stratigraphic, and structural research is necessary to test this hypothesis, including additional paleomagnetic investigations to determine the paleolatitudinal position of the Central Cordillera and adjacent tectonic terranes during the Triassic–Jurassic. Two stretching events are suggested for the Cretaceous: Berriasian–Hauterivian (144–127 Ma) and Aptian–Albian (121–102 Ma). During the Early Cretaceous, marine facies accumulated on an extensional basin system. Shallow-marine sedimentation ended at the end of the Cretaceous due to the accretion of oceanic terranes of the Western Cordillera. In Berriasian–Hauterivian subsidence curves, isopach maps and paleomagnetic data imply a (>180 km) wide, asymmetrical, transtensional half-rift basin existed, divided by the Santander Floresta horst or high. The location of small mafic intrusions coincides with areas of thin crust (crustal stretching factors >1.4) and maximum stretching of the subcrustal lithosphere. During the Aptian–early Albian, the basin extended toward the south in the Upper Magdalena Valley. Differences between crustal and subcrustal stretching values suggest some lowermost crustal decoupling between the crust and subcrustal lithosphere or that increased thermal thinning affected the mantle lithosphere. Late Cretaceous subsidence was mainly driven by lithospheric cooling, water loading, and horizontal compressional stresses generated by collision of oceanic terranes in western Colombia. Triassic transtensional basins were narrow and increased in width during the Triassic and Jurassic. Cretaceous transtensional basins were wider than Triassic–Jurassic basins. During the Mesozoic, the strike-slip component gradually decreased at the expense of the increase of the extensional component, as suggested by paleomagnetic data and lithosphere stretching values. During the Berriasian–Hauterivian, the eastern side of the extensional basin may have developed by reactivation of an older Paleozoic rift system associated with the Guaicáramo fault system. The western side probably developed through reactivation of an earlier normal fault system developed during Triassic–Jurassic transtension. Alternatively, the eastern and western margins of the graben may have developed along older strike-slip faults, which were the boundaries of the accretion of terranes west of the Guaicáramo fault during the Late Triassic and Jurassic. The increasing width of the graben system likely was the result of progressive tensional reactivation of preexisting upper crustal weakness zones. Lateral changes in Mesozoic sediment thickness suggest the reverse or thrust faults that now define the eastern and western borders of the EC were originally normal faults with a strike-slip component that inverted during the Cenozoic Andean orogeny. Thus, the Guaicáramo, La Salina, Bitúima, Magdalena, and Boyacá originally were transtensional faults. Their oblique orientation relative to the Mesozoic magmatic arc of the Central Cordillera may be the result of oblique slip extension during the Cretaceous or inherited from the pre-Mesozoic structural grains. However, not all Mesozoic transtensional faults were inverted. 相似文献
18.
《International Geology Review》2012,54(9):1072-1096
In this paper, we summarize results of studies on ophiolitic mélanges of the Bangong–Nujiang suture zone (BNSZ) and the Shiquanhe–Yongzhu–Jiali ophiolitic mélange belt (SYJMB) in central Tibet, and use these insights to constrain the nature and evolution of the Neo-Tethys oceanic basin in this region. The BNSZ is characterized by late Permian–Early Cretaceous ophiolitic fragments associated with thick sequences of Middle Triassic–Middle Jurassic flysch sediments. The BNSZ peridotites are similar to residual mantle related to mid-ocean-ridge basalts (MORBs) where the mantle was subsequently modified by interactions with the melt. The mafic rocks exhibit the mixing of various components, and the end-members range from MORB-types to island-arc tholeiites and ocean island basalts. The BNSZ ophiolites probably represent the main oceanic basin of the Neo-Tethys in central Tibet. The SYJMB ophiolitic sequences date from the Late Triassic to the Early Cretaceous, and they are dismembered and in fault contact with pre-Ordovician, Permian, and Jurassic–Early Cretaceous blocks. Geochemical and stratigraphic data are consistent with an origin in a short-lived intra-oceanic back-arc basin. The Neo-Tethys Ocean in central Tibet opened in the late Permian and widened during the Triassic. Southwards subduction started in the Late Triassic in the east and propagated westwards during the Jurassic. A short-lived back-arc basin developed in the middle and western parts of the oceanic basin from the Middle Jurassic to the Early Cretaceous. After the late Early Jurassic, the middle and western parts of the oceanic basin were subducted beneath the Southern Qiangtang terrane, separating the Nierong microcontinent from the Southern Qiangtang terrane. The closing of the Neo-Tethys Basin began in the east during the Early Jurassic and ended in the west during the early Late Cretaceous. 相似文献
19.
松辽盆地变质核杂岩和伸展断陷的构造特征及成因 总被引：18，自引：3，他引：15
文中讨论了松辽盆地北部中央基底隆起变质核杂岩和徐家围子伸展断陷的构造特征、成因和演化 ,重点讨论了下列问题 :( 1)中央基底隆起变质核杂岩具有科迪勒拉变质核杂岩的许多特征 ;( 2 )识别出组成中央基底隆起变质核杂岩的多层次、低角度韧性拆离体系 ,它们是使中地壳的中深变质岩层抽拉至上地壳的主要原因 ;( 3)穹窿状火山岩台地于晚侏罗世 ( 145.7±6.2 )Ma形成 ,受顶部拆离断层控制的伸展断陷于早白垩世 ( 133～ 12 0Ma)形成 ,而邻近顶部拆离断层的糜棱岩年龄为 ( 12 6.7± 1.54)Ma。这表明变质核杂岩的形成始于晚侏罗世。早白垩世递进的伸展构造与变质核杂岩较深部的部分上拱至地表相伴生 ,推测该变质核杂岩的上拱和剥露、火山岩台地和伸展断陷盆地的形成可能是由伊泽奈奇和亚洲板块陆陆碰撞后的地幔拆沉作用、地幔的岩浆底侵作用以及伸展垮塌作用联合造成的。 相似文献
20.
Changes of Late Mesozoic Tectonic Regimes around the Ordos Basin (North China) and their Geodynamic Implications 总被引：4，自引：0，他引：4
A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stress evolution was established from the field analyses of fault kinematics and constrained by stratigraphic contact relationships. The results show alternation of tectonic compressional and extensional regimes. The Ordos Basin and its surroundings were in weak N-S to NNE-SSW extension during the Early to Middle Jurassic, which reactivated E-W-trending basement fractures. The tectonic regime changed to a multi-directional compressional one during the Late Jurassic, which resulted in crustal shortening deformation along the marginal zones of the Ordos Basin. Then it changed to an extensional one during the Early Cretaceous, which rifted the western, northwestern and southeastern margins of the Ordos Basin. A NW-SE compression occurred during the Late Cretaceous and caused the termination of sedimentation and uplift of the Ordos Basin. This phased evolution of the late Mesozoic tectonic stress regimes and associated deformation pattern around the Ordos Basin best records the changes in regional geodynamic settings in East Asia, from the Early to Middle Jurassic post-orogenic extension following the Triassic collision between the North and South China Blocks, to the Late Jurassic multi-directional compressions produced by synchronous convergence of the three plates (the Siberian Plate to the north, Paleo-Pacific Plate to the east and Lhasa Block to the west) towards the East Asian continent. Early Cretaceous extension might be the response to collapse and lithospheric thinning of the North China Craton. 相似文献