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1.
西昆仑山前晚新生代沉积岩磁组构及构造意义   总被引:3,自引:1,他引:3  
西昆仑山前晚新生代沉积岩磁组构特征表明,沉积岩原生磁组构受后期构造活动改变。磁组构测试结果表明晚新生代沉积岩生较明显变形,岩石磁化率椭球体指示磁面理较发育,反映岩石受压扁型变形为主。磁化率椭球体最小轴方向为NW,指示该区最大主压应力为NW,与区域构造分析结果相一致。  相似文献   

2.
The thick (up to 17000 m) sequence of Albian, Upper Cretaceous, Paleogene, and Neogene ter-rigenous and less abundant volcanic rocks was deposited with breaks in sedimentation but without any tectonic rearrangements within the paleobasin bounded by the West Sakhalin and Tym-Poronai fault systems in the west and the east, respectively. The intensity of sagging progressively increased with time and reached a maximum in the late Miocene and Pliocene. The contemporary structure of the terrane started to form in the Pleistocene and has continued to form until now in the course of local inversion under the setting of dominating regional compression oriented in the ENE-E direction (60°–90°). The local indications of the SE-NW compression presumably are a result of pressure from the side of the Pacific Plate subducted beneath the Kurile-Kamchatka arc. Compression in these competing directions developed and develops contemporaneously within the same region.  相似文献   

3.
白垩纪:中国及邻区板块构造演化的一个重要变换期   总被引:46,自引:4,他引:42       下载免费PDF全文
吴根耀 《中国地质》2006,33(1):64-77
中国及邻区是一系列不同起源的微大陆(克拉通)和地块经多期增生和碰撞而形成的复合大陆,海西-印支旋回和新特提斯旋回在其形成中起了决定性的作用。侏罗纪末白垩纪初部分新特提斯洋(有人称中特提斯)闭合,亚洲大陆的雏形出现,白垩纪末新特提斯洋全面消减,亚洲大陆形成,因而白垩纪是中国及邻区板块构造演化的一个重要变换期。笔者从地球动力学系统的变换、构造格局的变换、北东向新生构造的出现和造山作用类型的多样化等方面论述了这一变换。这一变换集中表现在中国及邻区的构造演化由原来的南、北分异在白垩纪转变为东、西两部发生分异,西部以构造的继承性为特色,东部则新生构造起了主要作用。反映在地形一地貌上,早白垩世该区东高西低,白垩纪末开始出现今日的西高东低面貌。盆地发育和“盆”“山”系统也在白垩纪开始发生重要变换,说明东亚大陆边缘因向太平洋的蠕散而不断解体,大陆内部构造则日趋复杂。中国及邻区的这一实例再次说明必须坚持活动论构造观,以动态演化的思路来重塑区域大地构造演化。  相似文献   

4.
Eastern Venezuela is divided into three geologic-geographic provinces: The Guayana shield in the south; the Eastern Venezuelan basin in the central part; and the mountains of the Serranía del Interior and Cordillera de la Costa (Caribbean Cordillera) in the northern part. The stratigraphy and geological history are discussed, as reflected by rocks of presumably pre-Cambrian, ? Triassic-Jurassic, Cretaceous, Tertiary and Quaternary ages. From the Cretaceous onward, Eastern Venezuela north of the Guayana shield and east of the El BaÚl swell, forms part of a geosyncline, the axis of which shifted southward during its history. The position of this axis governed deposition and character of the sediments, which become more marine from south to north and from west to east. Orogenic and epeirogenic movements, particularly during Miocene and Pliocene time, transformed the Eastern Venezuelan sedimentary basin into two structural basins, namely the Maturín basin on the east and the Guárico basin on the west.  相似文献   

5.
The western edge of Patagonia, south of 47°S, experienced a major tectonic reorganization during the Tertiary. The Chile ridge, separating Nazca from Antarctica, collided obliquely with western Tierra del Fuego at about 14 Ma and the triple point migrated northwards to its present position at about 47°S. Consequently, the southern tip of South America has passed from a Miocene context of rapid oblique convergence (ENE–WSW at about 9 cm/yr) between Nazca and South America, to a Pliocene context of slow frontal convergence (EW at about 2 cm/yr) between Antarctica and South America. The Andean foreland fold-and-thrust belt lies on the eastern side of the Patagonian Cordillera and is well exposed along the northern shore of Lago Viedma (49°30′S). Structural observations, digital mapping, subsurface data, balancing of a cross-section and kinematic analysis of fault populations provide new information on the structure of the fold-and-thrust belt, the timing and style of deformation and their relationship with Tertiary plate tectonics. Along the studied transect, synsedimentary structures show that compressional deformation began at least during the Late Cretaceous, was ongoing during the syntectonic emplacement of the Lower Miocene granitic Monte Fitz Roy pluton and continued into the Pliocene. Folds and thrusts are thick-skinned in the west, and mostly thin-skinned above a décollement in Early Cretaceous black shales in the east. Analysis of fault populations, measured within Jurassic basement and its Cretaceous cover, provides subhorizontal principal directions of shortening, striking between E–W and ENE–WSW. Compressional deformation was associated with a major component of right-lateral wrenching parallel to the Cordillera.  相似文献   

6.
M. Manzoni 《Tectonophysics》1979,60(3-4):169-188
The magnetization of Lower Permian rocks from Sila has a mean direction D = 56.5°, I= +20.4° with 95 = 9.1° after correction for Upper Neogene tilting. A further correction for the attitude of the nappes after their Middle Miocene emplacement establishes paleolatitudes consistent with those from the Lower Permian Tethys. The remarkable internal consistency of the data has not supported the distinction of units with opposite vergences within the Sila crystalline nappes. The declination indicates that the Sila massif has rotated counter-clockwise by about 90° relative to the Apennines, Sardinia and the Southern Alps and therefore the well-known Apenninic rotation alone does not account for the total change of direction in tectonic transport. Accordingly, the structural trends of tectonic phases older than the emplacement time of the Calabrian nappes should no longer be referred to present-day geographic coordinates. The post-Late Cretaceous motion relative to the north Calabrian Apennines enhances the geotectonic role of the northern boundary of the Calabrian—Peloritan arc, since its sinistral-shear character permits both tectonic transport from the west and counter-clockwise motion during tectonic transport.  相似文献   

7.
In Alpine Corsica, the major tectonic event during the late Cretaceous was the thrusting to the west of an ophiolitic nappe and its sedimentary cover upon the Variscan basement and its Mesozoic cover. A detailed field survey shows that the basal contact of the nappe corresponds to a pluri-kilometric scale shear zone. Thus gneissified basement slices have been tectonically emplaced in the ophiolitic nappe. The thrusting was responsible for small scale structures: foliation, lineation and folds, initiated in a HP/LT metamorphic context. The deformation analysis shows that the finite strain ellipsoid lies in the constriction field close to that for plane strain. Moreover occurrences of rotational criteria in the XZ planes (sigmoidal micas, asymmetric pressure shadows, quartz C-axes fabrics) are in agreement with shear from east to west. All structural data from microscopic to kilometric scales, of which the most widespread is a transverse stretching lineation, can be interpreted by a simple shear model involving ductile synmetamorphic deformation. At the plate tectonic scale the ophiolitic obduction is due to intraoceanic subduction blocked by underthrusting of continental crust beneath oceanic lithosphere.  相似文献   

8.
Abstract

The oldest rocks in the Western Highlands of New Guinea are granite and metamorphic rocks, and these are unconformably overlain by an incomplete marine succession of Permian, Upper Jurassic, Cretaceous, Eocene, Oligocene and Miocene sediments with a maximum thickness of 34,000 ft. The sedimentary succession in the east of the region is much thicker than in the west. Jurassic seas transgressed from the east. Studies of the faunas and petrology of the sediments show that the western part of the region was out of range of the sources of Cretaceous vulcanism and slow pelagic sedimentation continued into the Lower Miocene. By the Middle Miocene a volcanic island arc had developed in the vicinity of the Lai Syncline and the sediments are of shallow-water type, rich in volcanic debris.

Both sediments and basement were folded into a number of anticlines and synclines at the end of the Pliocene. Vigorous erosion was followed by extensive Pleistocene vulcanism in the west. Pleistocene glaciation occurred in the Bismarck Range down to about 13,000 feet above sea-level.  相似文献   

9.
A geological cross-section between Vulcan Peak (Klamath Mountains) and Gold Beach (Pacific Ocean) shows several tectonic sheets thrust to the west. From the coast to the east, in tectonic superposition:
1. (1) The metamorphosed Franciscan Complex includes the Tithonian-Neocomian Otter Point and Dothan Formations, and, above them, a mélange unit and the Colebrooke Schist.
2. (2) Over them all lie the Red Flat, Game Lake and Snow Camp peridotite units, which are cut by granodioritic dykes of the Nevadan Orogeny and covered by Tithonian-Neocomian sediments (Myrtle Group). We have considered these granite-bearing ultramafic units as klippen thrust westward from the Klamath Mountains.
Several stages of deformation are superimposed:
1. (1) Disconformable upon the Otter Point Formation are the unmetamorphosed detrital Cape Sebastian and Hunters Cove Formations. Their Late Cretaceous age gives here an upper limit to the Franciscan metamorphism and tectonics.
2. (2) The first reworked fragments of Colebrooke Schist or ultramafic units are not found in the Campanian Cape Sebastian basal conglomerates (which are affected by some thrusting), but in the Middle Eocene Lookingglass Formation. Thus, major thrusting happened during Late Cretaceous and Early Tertiary times.
A geodynamic model is given: in southwestern Oregon, the Franciscan was probably deposited during Late Jurassic and earliest Cretaceous (Tithonian and Neocomian) times in a marginal basin, between an island arc to the west (Otter Point Formation in part) and the North American continent (Klamath Mountains) to the east. This Franciscan marginal basin was probably closed during the Early Cretaceous (i.e. Franciscan subduction). The present day structures (thrust plates, folds) are probably due mainly to the later collision between the continental margin and the arc and, to a much lesser degree, to early subduction, the marginal basin being consumed by subduction first, and then by collision.  相似文献   

10.
The Iraqi territory could be divided into four main tectonic zones; each one has its own characteristics concerning type of the rocks, their age, thickness and structural evolution. These four zones are: (1) Inner Platform (stable shelf), (2) Outer Platform (unstable shelf), (3) Shalair Zone (Terrain), and (4) Zagros Suture Zone. The first two zones of the Arabian Plate lack any kind of metamorphism and volcanism.The Iraqi territory is located in the extreme northeastern part of the Arabian Plate, which is colliding with the Eurasian (Iranian) Plate. This collision has developed a foreland basin that includes: (1) Imbricate Zone, (2) High Folded Zone, (3) Low Folded Zone and (4) Mesopotamia Foredeep.The Mesopotamia Foredeep, in Iraq includes the Mesopotamia Plain and the Jazira Plain; it is less tectonically disturbed as compared to the Imbricate, High Folded and Low Folded Zones. Quaternary alluvial sediments of the Tigris and Euphrates Rivers and their tributaries as well as distributaries cover the central and southeastern parts of the Foredeep totally; it is called the Mesopotamian Flood Plain. The extension of the Mesopotamia Plain towards northwest however, is called the Jazira Plain, which is covered by Miocene rocks.The Mesopotamia Foredeep is represented by thick sedimentary sequence, which thickens northwestwards including synrift sediments; especially of Late Cretaceous age, whereas on surface the Quaternary sediments thicken southeastwards. The depth of the basement also changes from 8 km, in the west to 14 km, in the Iraqi–Iranian boarders towards southeast.The anticlinal structures have N–S trend, in the extreme southern part of the Mesopotamia Foredeep and extends northwards until the Latitude 32°N, within the Jazira Plain, there they change their trends to NW–SE, and then to E–W trend.The Mesozoic sequence is almost without any significant break, with increase in thickness from the west to the east, attaining 5 km. The sequence forms the main source and reservoir rocks in the central and southern parts of Iraq. The Cenozoic sequence consists of Paleogene open marine carbonates, which grades upwards into Neogene lagoonal marine; of Early Miocene and evaporitic rocks; of Middle Miocene age, followed by thick molasses of continental clastics that attain 3500 m in thickness; starting from Late Miocene. The Quaternary sediments are very well developed in the Mesopotamia Plain and they thicken southwards to reach about 180 m near Basra city; in the extreme southeastern part of Iraq.The Iraqi Inner Platform (stable shelf) is a part of the Arabian Plate, being less affected by tectonic disturbances; it covers the area due to south and west of the Euphrates River. The main tectonic feature in this zone that had affected on the geology of the area is the Rutbah Uplift; with less extent is the Ga’ara High.The oldest exposed rocks within the Inner Platform belong to Ga’ara Formation of Permian age; it is exposed only in the Ga’ara Depression. The Permian rocks are overlain by Late Triassic rocks; represented by Mulussa and Zor Hauran formations, both of marine carbonates with marl intercalations. The whole Triassic rocks are absent west, north and east of Ga’ara Depression. Jurassic rocks, represented by five sedimentary cycles, overlie the Triassic rocks. Each cycle consists of clastic rocks overlain by carbonates, being all of marine sediments; whereas the last one (Late Jurassic) consists of marine carbonates only. All the five formations are separated from each other by unconformable contacts. Cretaceous rocks, represented by seven sedimentary cycles, overlie the Jurassic rocks. Marine clastics overlain by marine carbonates. Followed upwards (Late Cretaceous) by continental clastics overlain by marine carbonates; then followed by marine carbonates with marl intercalations, and finally by marine clastics overlain by carbonates; representing the last three cycles, respectively.The Paleocene rocks form narrow belt west of the Ga’ara Depression, represented by Early–Late Paleocene phosphatic facies, which is well developed east of Rutbah Uplift and extends eastwards in the Foredeep. Eocene rocks; west of Rutbah Uplift are represented by marine carbonates that has wide aerial coverage in south Iraq. Locally, east of Rutbah Uplift unconformable contacts are recorded between Early, Middle and Late Eocene rocks. During Oligocene, in the eastern margin of the Inner Platform, the Outer Platform was uplifted causing very narrow depositional Oligocene basin. Therefore, very restricted exposures are present in the northern part of the Inner Platform (north of Ga’ara Depression), represented by reef, forereef sediments of some Oligocene formations.The Miocene rocks have no exposures west of Rutbah Uplift, but north and northwestwards are widely exposed represented by Early Miocene of marine carbonates with marl intercalations. Very locally, Early Miocene deltaic clastics and carbonates, are interfingering with the marine carbonates. The last marine open sea sediments, locally with reef, represent the Middle Miocene rocks and fore reef facies that interfingers with evaporates along the northern part of Abu Jir Fault Zone, which is believed to be the reason for the restriction of the closed lagoons; in the area.During Late Miocene, the continental phase started in Iraq due to the closure of the Neo-Tethys and collision of the Sanandaj Zone with the Arabian Plate. The continental sediments consist of fine clastics. The Late Miocene – Middle Pliocene sediments were not deposited in the Inner Platform.The Pliocene–Pleistocene sediments are represented by cyclic sediments of conglomeratic sandstone overlain by fresh water limestone, and by pebbly sandstone.The Quaternary sediments are poorly developed in the Inner Platform. Terraces of Euphrates River and those of main valleys represent pleistocene sediments. Flood plain of the Euphrates River and those of large valleys represent Holocene sediments. Residual soil is developed, widely in the western part of Iraq, within the western marginal part of the Inner Platform.  相似文献   

11.
Neogene rift system configuration for the back-arc of southwest Japan, southern rim of the Japan Sea, is argued on the basis of reflection seismic interpretation. Divergent rifting and subsequent contraction provoked by an arc–arc collisional event are manifested by the formation of faulted grabens and their inverted deformation, respectively. We identified the following four Cenozoic tectonic epochs as a decomposition process of the eastern Eurasian margin based on reliable paleomagnetic data: (1) Plate margin rearrangement on a regional left-lateral fault through southwest Japan and Sikhote Alin, which constituted a continuous geologic province before the early Tertiary differential motion; (2) Early Tertiary clockwise rotation (>20°) of the east Tan-Lu block relative to the North China block; (3) Oligocene to early Miocene divergent rifting and spreading of the Japan Sea, which divided southwest Japan from the east Tan-Lu block; (4) Middle Miocene bending and back-arc inversion of southwest Japan caused by collision with the Izu-Bonin arc. According to the estimation of relative motions during these events, a paleogeographic reconstruction is presented through Cenozoic time.  相似文献   

12.
The stratigraphic architecture, structure and Cenozoic tectonic evolution of the Tan-Lu fault zone in Laizhou Bay, eastern China, are analyzed based on interpretations of 31 new 2D seismic lines across Laizhou Bay. Cenozoic strata in the study area are divided into two layers separated by a prominent and widespread unconformity. The upper sedimentary layer is made up of Neogene and Quaternary fluvial and marine sediments, while the lower layer consists of Paleogene lacustrine and fluvial facies. In terms of tectonics, the sediments beneath the unconformity can be divided into four main structural units: the west depression, central uplift, east depression and Ludong uplift. The two branches of the middle Tan-Lu fault zone differ in their geometry and offset: the east branch fault is a steeply dipping S-shaped strike-slip fault that cuts acoustic basement at depths greater than 8 km, whereas the west branch fault is a relatively shallow normal fault. The Tan-Lu fault zone is the key fault in the study area, having controlled its Cenozoic evolution. Based on balanced cross-sections constructed along transverse seismic line 99.8 and longitudinal seismic line 699.0, the Cenozoic evolution of the middle Tan-Lu fault zone is divided into three stages: Paleocene–Eocene transtension, Oligocene–Early Miocene transpression and Middle Miocene to present-day stable subsidence. The reasons for the contrasting tectonic features of the two branch faults and the timing of the change from transtension to transpression are discussed.  相似文献   

13.
The stratigraphic architecture, structure and Cenozoic tectonic evolution of the Tan-Lu fault zone in Laizhou Bay, eastern China, are analyzed based on interpretations of 31 new 2D seismic lines across Laizhou Bay. Cenozoic strata in the study area are divided into two layers separated by a prominent and widespread unconformity. The upper sedimentary layer is made up of Neogene and Quaternary fluvial and marine sediments, while the lower layer consists of Paleogene lacustrine and fluvial facies. In terms of tectonics, the sediments beneath the unconformity can be divided into four main structural units: the west depression, central uplift, east depression and Ludong uplift. The two branches of the middle Tan-Lu fault zone differ in their geometry and offset: the east branch fault is a steeply dipping S-shaped strike-slip fault that cuts acoustic basement at depths greater than 8 km, whereas the west branch fault is a relatively shallow normal fault. The Tan-Lu fault zone is the key fault in the study area, having controlled its Cenozoic evolution. Based on balanced cross-sections constructed along transverse seismic line 99.8 and longitudinal seismic line 699.0, the Cenozoic evolution of the middle Tan-Lu fault zone is divided into three stages: Paleocene–Eocene transtension, Oligocene–Early Miocene transpression and Middle Miocene to present-day stable subsidence. The reasons for the contrasting tectonic features of the two branch faults and the timing of the change from transtension to transpression are discussed.  相似文献   

14.
In this work we analyse and check the results of anisotropy of magnetic susceptibility (AMS) by means of a comparison with palaeostress orientations obtained from the analysis of brittle mesostructures in the Cabuérniga Cretaceous basin, located in the western end of the Basque–Cantabrian basin, North Spain. The AMS data refer to 23 sites including Triassic red beds, Jurassic and Lower Cretaceous limestones, sandstones and shales. These deposits are weakly deformed, and represent the syn-rift sequence linked to basins formed during the Mesozoic and later inverted during the Pyrenean compression. The observed magnetic fabrics are typical of early stages of deformation, and show oblate, triaxial and prolate magnetic ellipsoids. The magnetic fabric seems to be related to a tectonic overprint of an original, compaction, sedimentary fabric. Most sites display a NE–SW magnetic lineation that is interpreted to represent the stretching direction of the Early Cretaceous extensional stage of the basin, without recording of the Tertiary compressional events, except for sites with compression-related cleavage.Brittle mesostructures include normal faults, calcite and quartz tension gashes and joints, related to the extensional stage. The results obtained from joints and tension gashes show a dominant N–S to NE–SW, and secondary NW–SE, extension direction. Paleostresses obtained from fault analysis (Right Dihedra and stress inversion methods) indicate NW–SE to E–W, and N–S extension direction. The results obtained from brittle mesostructures show a complex pattern resulting from the superposition of several tectonic processes during the Mesozoic, linked to the tectonic activity related to the opening of the Bay of Biscay during the Early Cretaceous. This work shows the potential in using AMS analysis in inverted basins to unravel its previous extensional history when the magnetic fabric is not expected to be modified by subsequent deformational events. Brittle mesostructure analysis seems to be more sensitive to far-field stress conditions and record longer time spans, whereas AMS records deformation on the near distance, during shorter intervals of time.  相似文献   

15.
Al Jabal Al Akhdar is a NE/SW- to ENE/WSW-trending mobile part in Northern Cyrenaica province and is considered a large sedimentary belt in northeast Libya. Ras Al Hilal-Al Athrun area is situated in the northern part of this belt and is covered by Upper Cretaceous–Tertiary sedimentary successions with small outcrops of Quaternary deposits. Unmappable and very restricted thin layers of Palaeocene rocks are also encountered, but still under debate whether they are formed in situ or represent allochthonous remnants of Palaeocene age. The Upper Cretaceous rocks form low-lying to unmappable exposures and occupy the core of a major WSW-plunging anticline. To the west, south, and southeast, they are flanked by high-relief Eocene, Oligocene, and Lower Miocene rocks. Detailed structural analyses indicated structural inversion during Late Cretaceous–Miocene times in response to a right lateral compressional shear. The structural pattern is themed by the development of an E–W major shear zone that confines inside a system of wrench tectonics proceeded elsewhere by transpression. The deformation within this system revealed three phases of consistent ductile and brittle structures (D1, D2, and D3) conformable with three main tectonic stages during Late Cretaceous, Eocene, and Oligocene–Early Miocene times. Quaternary deposits, however, showed at a local scale some of brittle structures accommodated with such deformation and thus reflect the continuity of wrenching post-the Miocene. D1 deformation is manifested, in Late Cretaceous, via pure wrenching to convergent wrenching and formation of common E- to ENE-plunging folds. These folds are minor, tight, overturned, upright, and recumbent. They are accompanied with WNW–ESE to E–W dextral and N–S sinistral strike-slip faults, reverse to thrust faults and pop-up or flower structures. D2 deformation initiated at the end of Lutetian (Middle Eocene) by wrenching and elsewhere transpression then enhanced by the development of minor ENE–WSW to E–W asymmetric, close, and, rarely, recumbent folds as well as rejuvenation of the Late Cretaceous strike-slip faults and formation of minor NNW–SSE normal faults. At the end of Eocene, D2 led to localization of the movement within E–W major shear zone, formation of the early stage of the WSW-plunging Ras Al Hilal major anticline, preservation of the contemporaneity (at a major scale) between the synthetic WNW–ESE to E–W and ENE–WSW strike-slip faults and antithetic N–S strike-slip faults, and continuity of the NW–SE normal faults. D3 deformation is continued, during the Oligocene-Early Miocene, with the appearance of a spectacular feature of the major anticline and reactivation along the E–W shear zone and the preexisting faults. Estimating stress directions assumed an acted principal horizontal stress from the NNW (N33°W) direction.  相似文献   

16.
喀什凹陷西部位于塔里木盆地、帕米尔构造带和南西天山构造带的交接处,在新生代以来接受了大量来自于南天山和帕米尔的沉积物,并记录了新生代以来南西天山构造抬升的信息。本文选择了位于南西天山山前的铁热克萨孜晚新生代剖面开展磁组构研究。铁热克萨孜剖面晚新生代沉积序列自下而上为一套整体上粒度逐渐变粗的陆相沉积,由河流湖泊相逐渐变为扇三角洲相,并最终变为冲积扇相和洪积扇相。岩石磁学结果的分析表明剖面晚新生代沉积序列中的主要磁性矿物为赤铁矿,仅在帕卡布拉克组下部为以磁铁矿为主。磁组构结果表明该剖面的磁组构为早期的同沉积弱变形磁组构,指示了当时构造应力的方向和变化。在22.1Ma以来南西天山山前晚新生代磁组构所反映的构造应力整体上为N-S向挤压,这与帕米尔和南天山的南北向持续汇聚作用相一致。在安居安组和西域组时期,应力方向由N-S向挤压变为NNE-SSW向挤压,这一变化可能是由塔拉斯-费尔干纳断裂的活动所导致的。塔拉斯-费尔干纳断裂(Talas-Fergana Fault, TFF)的右行走滑活动可能吸收了南西天山晚新生代的部分应变量,使得南西天山山前的构造应变量相对TFF以东的南天山山前地区要更小,使得TFF以东的晚新生代山前冲断带活动相对TFF以西地区更为发育和活跃。  相似文献   

17.
东海盆地中、新生代盆架结构与构造演化   总被引:6,自引:0,他引:6  
基于地貌、钻井、岩石测年和地震等资料,分析盆地地层分布、盆架结构、构造单元划分和裂陷迁移规律,结果表明东海盆地由台北坳陷、舟山隆起、浙东坳陷、钓鱼岛隆褶带和冲绳坳陷构成,是以新生代沉积为主、中生代沉积为辅的大型中、新生代叠合含油气盆地;古元古代变质岩系构成了盆地的基底。该盆地不仅是印度-太平洋前后相继的动力体系作用下形成的西太平洋沟-弧-盆构造体系域一部分,而且也是古亚洲洋动力体系作用下形成的古亚洲洋构造域和特提斯洋动力体系作用下形成的特提斯洋构造域一部分,晚侏罗世至早白垩世经历了构造体制转换,盆地格局发生重大变革,早白垩世以前主要受古亚洲-特提斯洋构造体制影响的强烈挤压造山和地壳增厚作用演变为早白垩世以来主要受太平洋构造体制控制的陆缘伸展裂陷和岩石圈减薄作用,经历侏罗纪古亚洲-特提斯构造体制大陆边缘拗陷和白垩纪以来太平洋构造体制弧后裂陷两大演化阶段。白垩纪以来太平洋构造体制的弧后裂陷演化阶段可细分为早白垩世至始新世裂陷期、渐新世至晚中新世拗陷期和中新世末至全新世裂陷期。  相似文献   

18.
Fold-interference patterns in the Bowen Basin,northeastern Australia   总被引:1,自引:1,他引:0  
Deformation patterns of Paleozoic and Mesozoic strata in eastern Australia are evidence of a structural and tectonic history that included multiple periods of deformation with variable strain intensities and orientations. Detailed analysis of structural data from the Bowen Basin in northeastern Australia reveals previously undescribed, north–south elongate, Type-1 fold-interference patterns. The Bowen Basin structures have similar orientations to previously described interference patterns of equivalent scale in upper Paleozoic strata of the New England Orogen and Sydney Basin of eastern Australia. The east Australian folds with north–south-trending axes most likely formed during late stages of the Permian–Triassic Hunter–Bowen Orogeny, and they were subsequently refolded around east–west axes during post 30 Ma collision of the Indo-Australian plate with the Eurasian and Pacific plates. The younger, east–west-trending folds have orientations that are well aligned with the present-day horizontal stress field of much of eastern Australia, raising the possibility that they are active structures.  相似文献   

19.
试论南中国海盆地新生代板块构造及盆地动力学   总被引:2,自引:0,他引:2       下载免费PDF全文
南海地处欧亚、印度—澳大利亚和菲律宾海板块的交互带,是西太平洋地区面积最大的边缘海之一,其成因机制和演化过程对探讨特提斯构造域和太平洋构造域相互作用及油气勘探等问题具有重要意义,虽备受关注但仍存争议.综合目前该区及外围已有的大地构造等方面的资料,本文从探讨南海外围的构造格架及中-新生代演化过程入手,分析了南海及外围板块...  相似文献   

20.
In this study, we address the late Miocene to Recent tectonic evolution of the North Caribbean (Oriente) Transform Wrench Corridor in the southern Sierra Maestra mountain range, SE Cuba. The region has been affected by historical earthquakes and shows many features of brittle deformation in late Miocene to Pleistocene reef and other shallow water deposits as well as in pre-Neogene, late Cretaceous to Eocene basement rocks. These late Miocene to Quaternary rocks are faulted, fractured, and contain calcite- and karst-filled extension gashes. Type and orientation of the principal normal palaeostress vary along strike in accordance with observations of large-scale submarine structures at the south-eastern Cuban margin. Initial N–S extension is correlated with a transtensional regime associated with the fault, later reactivated by sinistral and/or dextral shear, mainly along E–W-oriented strike-slip faults. Sinistral shear predominated and recorded similar kinematics as historical earthquakes in the Santiago region. We correlate palaeostress changes with the kinematic evolution along the boundary between the North American and Caribbean plates. Three different tectonic regimes were distinguished for the Oriente transform wrench corridor (OTWC): compression from late Eocene–Oligocene, transtension from late Oligocene to Miocene (?) (D1), and transpression from Pliocene to Present (D2–D4), when this fault became a transform system. Furthermore, present-day structures vary along strike of the Oriente transform wrench corridor (OTWC) on the south-eastern Cuban coast, with dominantly transpressional/compressional and strike-slip structures in the east and transtension in the west. The focal mechanisms of historical earthquakes are in agreement with the dominant ENE–WSW transpressional structures found on land.  相似文献   

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