共查询到20条相似文献，搜索用时 31 毫秒
1.
《Tectonophysics》1987,135(4):307-327
The Kutch-Saurashtra, Cambay and Narmada basins are pericontinental rift basins in the western margin of the Indian craton. These basins were formed by rifting along Precambrian tectonic trends. Interplay of three major Precambrian tectonic trends of western India, Dharwar (NNW-SSE), Aravalli-Delhi (NE-SW) and Satpura (ENE-WSW), controlled the tectonic style of the basins. The geological history of the basins indicates that these basins were formed by sequential reactivation of primordial faults. The Kutch basin opened up first in the Early Jurassic (rifting was initiated in Late Triassic) along the Delhi trend followed by the Cambay basin in the Early Cretaceous along the Dharwar trend and the Narmada basin in Late Cretaceous time along the Satpura trend. The evolution of the basins took place in four stages. These stages are synchronous with the important events in the evolution of the Indian sub-continent—its breakup from Gondwanaland in the Late Triassic-Early Jurassic, its northward drifting during the Jurassic-Cretaceous and collision with the Asian continent in the Early Tertiary. The most important tectonic events occurred in Late Cretaceous time. The present style of the continental margins of India evolved during Early Tertiary time.The Saurashtra arch, the extension of the Aravalli Range across the western continental shelf, subsided along the eastern margin fault of the Cambay basin during the Early Cretaceous. It formed an extensive depositional platform continuous with the Kutch shelf, for the accumulation of thick deltaic sediments. A part of the Saurashtra arch was uplifted as a horst during the main tectonic phase in the Late Cretaceous.The present high thermal regime of the Cambay-Bombay High region is suggestive of a renewed rifting phase. 相似文献
2.
3.
The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains ∼1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early–Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue Nile Basin has evolved in three main phases: (1) pre‐sedimentation phase, include pre‐rift peneplanation of the Neoproterozoic basement rocks, possibly during Palaeozoic time; (2) sedimentation phase from Triassic to Early Cretaceous, including: (a) Triassic–Early Jurassic fluvial sedimentation (Lower Sandstone, ∼300 m thick); (b) Early Jurassic marine transgression (glauconitic sandy mudstone, ∼30 m thick); (c) Early–Middle Jurassic deepening of the basin (Lower Limestone, ∼450 m thick); (d) desiccation of the basin and deposition of Early–Middle Jurassic gypsum; (e) Middle–Late Jurassic marine transgression (Upper Limestone, ∼400 m thick); (f) Late Jurassic–Early Cretaceous basin‐uplift and marine regression (alluvial/fluvial Upper Sandstone, ∼280 m thick); (3) the post‐sedimentation phase, including Early–Late Oligocene eruption of 500–2000 m thick Lower volcanic rocks, related to the Afar Mantle Plume and emplacement of ∼300 m thick Quaternary Upper volcanic rocks. The Mesozoic to Cenozoic units were deposited during extension attributed to Triassic–Cretaceous NE–SW‐directed extension related to the Mesozoic rifting of Gondwana. The Blue Nile Basin was formed as a NW‐trending rift, within which much of the Mesozoic clastic and marine sediments were deposited. This was followed by Late Miocene NW–SE‐directed extension related to the Main Ethiopian Rift that formed NE‐trending faults, affecting Lower volcanic rocks and the upper part of the Mesozoic section. The region was subsequently affected by Quaternary E–W and NNE–SSW‐directed extensions related to oblique opening of the Main Ethiopian Rift and development of E‐trending transverse faults, as well as NE–SW‐directed extension in southern Afar (related to northeastward separation of the Arabian Plate from the African Plate) and E–W‐directed extensions in western Afar (related to the stepping of the Red Sea axis into Afar). These Quaternary stress regimes resulted in the development of N‐, ESE‐ and NW‐trending extensional structures within the Blue Nile Basin. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
Elizabeth M. Truswell 《Australian Journal of Earth Sciences》2013,60(3-4):343-356
Fifty‐three sea‐floor samples close to Antarctica collected by Douglas Mawson during the Australasian Antarctic Expedition of 1911–1914 have beeen analysed for recycled palynomorphs. The distribution of the recycled microfossils provides a broad guide to the position of hidden sedimentary sequences on the Antarctic continental margin. The samples were dredged off the East Antarctic coast between 91°E and 146°E. In three distinct ‐areas, concentrations of recycled palynomorphs suggest the presence nearby of eroding sedimentary sequences. Near the western edge of the Shackleton Ice Shelf the recycled suite suggests Early to Late Permian, Late Jurassic to mid‐Cretaceous, and Late Cretaceous to Early Tertiary sediments, with evidence for marine influence only in the Tertiary. Samples from the outer edge of the continental shelf and slope east of Cape Carr indicate Early Cretaceous and Late Cretaceous to Early Tertiary sequences, and the same age span is suggested by samples from the western side of the Mertz Glacier Tongue; in this area radio echosounding has suggested that inland sedimentary basins intersect the coast. The sedimentary sequence predicted for the Shackleton Ice Shelf area probably faced the open Indian Ocean, at least since the Mesozoic. Cretaceous sequences predicted for the other localities occur at points on the Antarctic coast where they would be expected on the basis of most reconstructions. The area east of Cape Carr has as its conjugate’ coast part of the Great Australian Bight Basin; that off the Mertz Glacier, the area west of the Otway Basin. At both these areas on the southern Australian margin thick Cretaceous rift‐valley sequences occur. 相似文献
5.
Alfred Whittaker Brian E. Leveridge 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(4):718-744
The North Devon Basin, situated in a more proximal passive margin regime than the rift basins to the south, is not constrained but its succession is thought to represent in large part the sediments debouched from a northerly hinterland. Rather than that immediate source being South Wales an original location of the basin well to the south-east and west of the Ardennes massif is considered probable, with its present position being attained by Carboniferous displacement along the Bristol Channel-Bray Fault. The basin's thick (6000 m) succession comprises terrestrial and marine deposits that form two major sedimentary cycles, which are apparently closely linked to rift basin formation to the south. The GCR sites span a relatively straightforward shelf succession that extends from the late Early Devonian to the Carboniferous. The sedimentology, palaeontology, and depositional environments of terrestrial and marine facies lithostratigraphical units are detailed, some sites providing the macrofossil assemblages important in the identification and definition by Sedgwick and Murchison of the Devonian System. 相似文献
6.
在内蒙古林西县西拉木伦断裂带内发育岩株状产出并具有不同程度变形特征的闪长岩体, 岩体侵入到双井片岩中.对该闪长岩进行了岩石学、地球化学、锆石LA-ICPMS U-Pb年龄和角闪石40Ar-39Ar年龄的研究.结果表明内蒙古林西县西拉木伦断裂带内的变形闪长岩侵位于早二叠世, 其锆石LA-ICPMS U-Pb年龄为286±1 Ma.岩浆来源于俯冲带流体/熔体交代作用而形成的富集地幔.岩石遭受了早侏罗世绿帘角闪岩相变质作用, 角闪石40Ar-39Ar年龄为188.7±1.4 Ma.结合研究区及邻区近年来的新成果认为索伦缝合带早古生代以来的镁铁质岩石均显示来源于相对富集LILE、LREE的地幔, 与俯冲流体或熔体的改造作用相关, 并且随着时代的更新改造程度显示增强的趋势.索伦缝合带在晚石炭世(~310 Ma)之前发生过闭合碰撞, 晚石炭世-早二叠世(~310~276 Ma)处于后造山伸展的背景, 在伸展环境下形成了华北北缘该时期广泛分布的闪长岩-花岗闪长岩带, 报道的闪长岩即为该时期的产物.晚二叠世缝合带局部区域存在洋盆, 洋盆的闭合导致了晚二叠世-中三叠世(~272~230 Ma)索伦缝合带的最终碰撞缝合, 最终碰撞缝合在空间上的不均一性形成了缝合带内该时期大量并存的同碰撞花岗岩和后碰撞花岗岩.索伦缝合带的缝合导致华北板块与其北部各微陆块的拼合, 此时蒙古-鄂霍次克海作为古太平洋的一个分支北东向展布于西伯利亚板块和拼合后的华北板块之间.早侏罗世蒙古-鄂霍次克海在蒙古东北部发生闭合, 本文报道的角闪石40Ar-39Ar年龄记录了洋壳闭合后陆-陆碰撞的变质时间, 之后研究区进入后造山伸展的环境.此时在古太平洋板块向华北板块俯冲应力的共同作用下, 华北东部在侏罗纪出现挤压机制与拉张机制的多次转换.晚侏罗世古太平洋板块俯冲方向转变后, 中国东部进入持续的拉张背景, 并转入西太平洋构造域的范畴. 相似文献
7.
Evolution, Migration, Controlling Factors and Forming Setting of Mesozoic Basins in Western Shandong
ZHANG Zhongyi WU Ganguo Guo Jinghui ZHANG Da Key Laboratory of Lithospheric Tectonics Lithoprobing Technology Ministry of Education University of Geosciences Beijing E-mail: zy_zhang@sina.com Institute of Geology Geophysics Chinese Academy of Sciences Beijing 《《地质学报》英文版》2005,79(4):519-532
The distinctive topography in western Shandong province consists of several NW-WNW-trending mountain ranges and intervening basins. Basins, in which late-stage sediments to the south have progressively overlapped the earlier sediments and ＂basement＂ rocks of the hanging-wall block, are bounded by S-SW-dipping normal faults to the north. Basin analysis reveals the Jurassic-Cretaceous sedimentary rocks accumulated both within the area of crustal extension and during extensional deformation; they contain a record of a sequence of tectonic events during stretching and can be divided into four tectonic-sequence episodes. These basins were initially developed as early as ca. 200 Ma in the northern part of the study area, extending dominantly N-S from the Early Jurassic until the Late Cretaceous. Although with a brief hiatus due to changes in stress field, to keep uniform N-S extensional polarity in such a long time as 130 Ma requires a relatively stable tectonic controlling factor responsible for the NW- and E-W-extensional basins. The formation of the extensional basins is partly concurrent with regional magmatism, but preceded magmatism by 40 Ma. This precludes a genetic link between local magmatism and extension during the Mesozoic. Based on integrated studies of basins and deformation, we consider that the gravitational collapse of the early overthickened continental crust may be the main tectonic driver for the Mesozoic extensional basins. From the Early Jurassic, dramatic reduction in north-south horizontal compressive stress made the western Shandong deformation belt switch from a state of failure under shortening to one dominated by extension and the belt gravitationally collapsed and horizontally spread to the south until equilibrium was established; synchronously, the normal faults and basins were developed based on the model of simple-shear extensional deformation. This may be relative to the gravitational collapse of the Mesozoic plateau in eastern China. 相似文献
8.
William Bosworth 《International Journal of Earth Sciences》1994,83(4):671-688
Large areas of north-east Africa were dominated by regional extension in the Late Phanerozoic. Widespread rifting occurred in the Late Jurassic, with regional extension culminating in the Cretaceous and resulting in the greatest areal extent and degree of interconnection of the west, central and north African rift systems. Basin reactivation continued in the Paleocene and Eocene and new rifts probably formed in the Red Sea and western Kenya. In the Oligocene and Early Miocene, rifts in Kenya, Ethiopia and the Red Sea linked and expanded to form the new east African rift system.This complex history of rifting resulted in failed rift basins with low to high strain geometries, a range of associated volcanism and varying degrees of interaction with older structures. One system, the Red Sea rift, has partially attained active seafloor spreading. From a comparison of these basins, a general model of three-dimensional rift evolution is proposed. Asymmetrical crustal geometries dominated the early phases of these basins, accompanied by low angle normal faulting that has been observed at least locally in outcrop. As rifting progressed, the original fault and basin forms were modified to produce larger, more through-going structures. Some basins were abandoned, others experienced reversals in regional dip and, in general, extension and subsidence became focused along narrower zones near the rift axes. The final transition to oceanic spreading was accomplished in the Red Sea by a change to high angle, planar normal faulting and diffuse dike injection, followed by the organization of an axial magma chamber. 相似文献
9.
The closure of the western part of the Neotethys Ocean started in late Early Jurassic. The Middle to early Late Jurassic contraction
is documented in the Berchtesgaden Alps by the migration of trench-like basins formed in front of a propagating thrust belt.
Due to ophiolite obduction these basins propagated from the outer shelf area (=Hallstatt realm) to the interior continent
(=Hauptdolomit/Dachstein platform realm). The basins were separated by nappe fronts forming structural highs. This scenario
mirrors syn-orogenic erosion and deposition in an evolving thrust belt. Active basin formation and nappe thrusting ended around
the Oxfordian/Kimmeridgian boundary, followed by the onset of carbonate platforms on structural highs. Starved basins remained
between the platforms. Rapid deepening around the Early/Late Tithonian boundary was induced by extension due to mountain uplift
and resulted in the reconfiguration of the platforms and basins. Erosion of the uplifted nappe stack including obducted ophiolites
resulted in increased sediment supply into the basins and final drowning and demise of the platforms in the Berriasian. The
remaining Early Cretaceous foreland basins were filled up by sediments including siliciclastics. The described Jurassic to
Early Cretaceous history of the Northern Calcareous Alps accords with the history of the Western Carpathians, the Dinarides,
and the Albanides, where (1) age dating of the metamorphic soles prove late Early to Middle Jurassic inneroceanic thrusting
followed by late Middle to early Late Jurassic ophiolite obduction, (2) Kimmeridgian to Tithonian shallow-water platforms
formed on top of the obducted ophiolites, and (3) latest Jurassic to Early Cretaceous sediments show postorogenic character. 相似文献
10.
从原始塔里木板块的演化入手,结合构造单元的划分,将巴丹吉林地区中生代地层划分为塔里木地层区的北山地层分区、阿拉善地层分区（包括北缘小区和南缘小区）和河西走廊地层分区,基本理顺了各分区（小区）中生代地层的命名系统,为研究各分区的沉积 构造古地理演化和恢复中生代原形盆地奠定了基础 相似文献
11.
《International Geology Review》2012,54(12):1528-1556
ABSTRACTThe intra-continental orogeny and tectonic evolution of the Mesozoic Yanshan fold-thrust belt (YFTB) in the northern North China Craton (NCC) have been strongly debated. Here, we focus on the Shangyi basin, located in the centre of the YFTB. An integrated analysis of sedimentary facies, palaeocurrents, clast compositions, and detrital zircon dating of sediments was adopted to determine the palaeogeography, provenance, basin evolution, and intra-continental orogenic process. The Shangyi basin comprises the well-exposed Early–early Middle Jurassic Xiahuayuan Formation and the Longmen Formation, and the Late Jurassic–Early Cretaceous Tuchengzi Formation. Based on the 18 measured sections, five facies associations – including alluvial fan, fluvial, delta, lacustrine, and eolian facies – have been identified and described in detail. The onset of the Shangyi basin was filled with fluvial, deltaic, and lacustrine deposits controlled by the normal fault bounding the northern basin, corresponding to the pre-orogeny. In the Middle Jurassic, the cobble–boulder conglomerates of alluvial fan, as molasse deposits, were compatible with the syn-orogeny of the Yanshan movement, which played a critical role in northern North China and even East Asia. After the depositional break in the Middle–Late Jurassic, the Shangyi basin, controlled by the normal fault present in the north of the basin, re-subsided and quickly expanded southward with thick sedimentation, which is correlative with the post-orogeny. Combined with A-type granites, metamorphic core complexes, mafic dikes, and rift basins of the Late Jurassic–early Early Cretaceous present in the northern NCC and Mongolia, significant extension was widespread in the northern NCC and even in northeast Asia. Moreover, vertical changes of provenance indicate that the Taihang Mountain and the Inner Mongolia palaeo-uplift (IMPU) present at the west and north of the basin, respectively, experienced uplift twice in the Middle–Late Jurassic and Early Cretaceous, resulting in a regional depositional break. 相似文献
12.
侏罗纪时东南亚大陆上形成两个大盆地,西为海相盆地,东为陆相红盆。白垩纪时大盆地闭合或解体。第三纪出现裂谷盆地,其发育受燕山期构造格局控制;拉张应力自南向北变弱,裂谷发育自南向北变晚。第四纪为上叠盆地阶段。滇西与泰国各时期盆地的对比研究有助于更好地认识其演化特征,恢复东南亚大陆侏罗纪以来不断碎裂、局部解体的历史。 相似文献
13.
侏罗纪时东南亚大陆上形成两个大盆地,西为海相盆地,东为陆相红盆。白垩纪时大盆地闭合或解体。第三纪出现裂谷盆地,其发育受燕山期构造格局控制;拉张应力自南向北变弱,裂谷发育自南向北变晚。第四纪为上叠盆地阶段。滇西与泰国各时期盆地的对比研究有助于更好地认识其演化特征,恢复东南亚大陆侏罗纪以来不断碎裂、局部解体的历史。 相似文献
14.
S. Mazur P. Aleksandrowski K. Turniak L. Krzemiński K. Mastalerz A. Górecka-Nowak L. Kurowski P. Krzywiec A. Żelaźniewicz M. C. Fanning 《International Journal of Earth Sciences》2010,99(1):47-64
The Carboniferous foreland basin of western Poland contains a coherent succession of late Viséan through Westphalian turbidites
derived from a uniform group of sources located within a continental magmatic arc. Detrital zircon geochronology indicates
that two main crustal components were present in the source area of Namurian A sediments. They represent Late Devonian and
Early Carboniferous ages, respectively. The detritus from Westphalian D beds is much more diversified and contains admixture
of Late Carboniferous zircons suggesting rapid unroofing of Variscan igneous intrusions in the hinterland between Namurian
A and Westphalian D times. Tectonic repetitions of tens of metres thick fault-bounded stratigraphic intervals, recorded in
several wells, provide evidence for compressional regime that occurred in the SW part of the Carboniferous basin not earlier
than during the Westphalian C and produced NW–SE trending folds, concordant with the structural grain of the adjacent, NE
part of the Bohemian Massif. 相似文献
15.
华北克拉通东部南北缘中生代火山-沉积格局及其构造转折过程 总被引：3，自引：0，他引：3
通过华北克拉通东部北缘和南缘盆地充填序列和盆地分布演化对比研究,解析了该区中生代构造转折过程。研究发现两侧盆地均大致从早侏罗世开始发育,约以晚侏罗世为界,之前盆地充填记录反映以挤压作用、岩石圈增厚为主,之后以陆内伸展、岩石圈减薄为主,显示晚侏罗世明显的构造转折,并且地壳浅部的构造体制转变均滞后于岩石圈深部构造环境的变化。然而,两侧盆地演化也有明显差别：①北缘燕辽地区从早侏罗世到白垩纪,发育了多层系的从基性、中基性到中酸性的火山岩及火山碎屑岩组合,而南缘合肥盆地仅在晚侏罗世早白垩世产出钙碱性火山岩及火山碎屑岩组合,反映出不同的深部构造过程和源区特征;②北缘的岩石圈减薄可能始于约163 Ma,南缘明显的岩石圈减薄则始于约149 Ma,而反映在盆地构造与充填尺度上的伸展作用分别对应于大约145 Ma和132 Ma;③晚侏罗世构造转折期,北缘燕辽地区粗碎屑沉积以河流体系为主,反映盆山地势高差较小;而南缘该期发育冲积扇体系,盆山地势高差较大;④北缘盆地沉积中心迁移规律复杂,而南缘总体呈现由南向北的迁移趋势。显然,大别山碰撞造山和后造山期强烈的隆升和剥露对南缘盆地演化具有极大的主导和制约作用,而北缘则显示出强烈的壳幔相互作用并伴有区域性的陆内挤压推覆（转折前）和张裂 伸展（转折后）交替的特点。华北克拉通晚中生代构造转折的时限北缘较南缘早,说明诱发这一转折事件的区域构造动力可能首先与华北北部壳幔相互作用密切关联。 相似文献
16.
The Dead Sea depression sensu stricto, forms the deepest continental part of the Dead Sea rift, a transfer which separates the Levanthine and Arabian plates. It is occupied by three distinct sedimentary bodies, deposited in basins whose depocenters are displaced northward with time. They are: the continental red beds of the Hazeva Formation (Miocene), the Bira-Lido-Gesher marls and the exceptionally thick rocksalt of the Sedom Formation (Pliocene—Early Pleistocene), and the successive Amora, Lisan and Dead Sea evaporites and clastics (Early Pleistocene—Recent). Lengthwise and crosswise asymmetries of these sedimentary basins and their respective depocenters are due to: leftlateral shear combined with anticlockwise rotation of the Arabian (eastern) plate; steeper faulting of the crustal eastern margin than of the western sedimentary margin, and modification of depositional pattern by twice filling up of basins, by Hazeva red beds during Late Miocene pause of shear and by Sedom rocksalt during Pliocene marine ingression. 相似文献
17.
Mustafa Abdullatif As-Saruri Rasoul Sorkhabi Rasheed Baraba 《Arabian Journal of Geosciences》2010,3(4):515-527
This paper describes the updated stratigraphy, structural framework and evolution, and hydrocarbon prospectivity of the Paleozoic, Mesozoic and Cenozoic basins of Yemen, depicted also on regional stratigraphic charts. The Paleozoic basins include (1) the Rub’ Al-Khali basin (southern flanks), bounded to the south by the Hadramawt arch (oriented approximately W–E) towards which the Paleozoic and Mesozoic sediments pinch out; (2) the San’a basin, encompassing Paleozoic through Upper Jurassic sediments; and (3) the southern offshore Suqatra (island) basin filled with Permo-Triassic sediments correlatable with that of the Karoo rift in Africa. The Mesozoic rift basins formed due to the breakup of Gondwana and separation of India/Madagascar from Africa–Arabia during the Late Jurassic/Early Cretaceous. The five Mesozoic sedimentary rift basins reflect in their orientation an inheritance from deep-seated, reactivated NW–SE trending Infracambrian Najd fault system. These basins formed sequentially from west to east–southeast, sub-parallel with rift orientations—NNW–SSE for the Siham-Ad-Dali’ basin in the west, NW–SE for the Sab’atayn and Balhaf basins and WNW–ESE for the Say’un-Masilah basin in the centre, and almost E–W for the Jiza’–Qamar basin located in the east of Yemen. The Sab’atayn and Say’un–Masilah basins are the only ones producing oil and gas so far. Petroleum reservoirs in both basins have been charged from Upper Jurassic Madbi shale. The main reservoirs in the Sab’atayn basin include sandstone units in the Sab’atayn Formation (Tithonian), the turbiditic sandstones of the Lam Member (Tithonian) and the Proterozoic fractured basement (upthrown fault block), while the main reservoirs in the Say’un–Masilah basin are sandstones of the Qishn Clastics Member (Hauterivian/Barremian) and the Ghayl Member (Berriasian/Valanginian), and Proterozoic fractured basement. The Cenozoic rift basins are related to the separation of Arabia from Africa by the opening of the Red Sea to the west and the Gulf of Aden to the south of Yemen during the Oligocene-Recent. These basins are filled with up to 3,000 m of sediments showing both lateral and vertical facies changes. The Cenozoic rift basins along the Gulf of Aden include the Mukalla–Sayhut, the Hawrah–Ahwar and the Aden–Abyan basins (all trending ENE–WSW), and have both offshore and onshore sectors as extensional faulting and regional subsidence affected the southern margin of Yemen episodically. Seafloor spreading in the Gulf of Aden dates back to the Early Miocene. Many of the offshore wells drilled in the Mukalla–Sayhut basin have encountered oil shows in the Cretaceous through Neogene layers. Sub-commercial discovery was identified in Sharmah-1 well in the fractured Middle Eocene limestone of the Habshiyah Formation. The Tihamah basin along the NNW–SSE trending Red Sea commenced in Late Oligocene, with oceanic crust formation in the earliest Pliocene. The Late Miocene stratigraphy of the Red Sea offshore Yemen is dominated by salt deformation. Oil and gas seeps are found in the Tihamah basin including the As-Salif peninsula and the onshore Tihamah plain; and oil and gas shows encountered in several onshore and offshore wells indicate the presence of proven source rocks in this basin. 相似文献
18.
巴颜喀拉残留洋盆的沉积特征 总被引：6，自引：4，他引：6
巴颜喀拉盆地垂向沉积序列表明：盆地于早古生代被动陆缘的浅海基础上裂陷、拉开，泥盆纪贯通，早石炭世洋盆扩展为成熟大洋，晚石炭世洋盆北部开始消减、南部继续扩张，晚二叠世-中三叠世进入残留洋阶段，晚三叠世转化为周缘前陆盆地．三叠纪末完全闭合，盆地自形成到消亡为一个连续的沉积和地质构造演化过程。其主体由早中三叠世深海沉积、典型浊积岩复理石和晚三叠世浅海复理石、风暴岩沉积、海相磨拉石构成，北部零星出露了中二叠世海山型沉积，昆南结合带以北有早中三叠世岛弧沉积。以盆地为中心具有向南北两侧陆块双向相背俯冲的极性特点，东西两端的碰撞造山不迟于晚二叠世。总体反映了古特提斯晚二叠世-中三叠世的残留洋盆性质和主洋域之所在。 相似文献
19.
《Earth》2009,92(1-4):27-76
In this study we reconstruct the evolution of the northern New England passive margin whose development has been influenced by Pleistocene glaciations. The morphology of the northern New England shelf is rather unique consisting of a inner lowland, the Gulf of Maine, with an average depth of 150 m and an area of 90,700 km2 and Georges Bank, a high whose crest is less than 40 m deep and has an area of 27,000 km2. The bank's northern slope, facing the Gulf of Maine, has a maximum relief of 377 m. On the seaward side of Georges Bank is the 2000 m high continental slope deeply cut by canyons. Two channels, Northeast and Great South Channels, east and west of Georges Bank, provide passageways from the Gulf of Maine to the open sea. This morphology was acquired by a combination of Tertiary fluvial erosion, Pleistocene glacial erosion/deposition and Pleistocene/Holocene marine processes. Fluvial/glacial erosion in the Gulf of Maine was so extensive as to expose basement, thus making it possible to map the various terranes making up this foundation. These terranes include the pre-Carboniferous Avalon and Meguma units, a Carboniferous–Permian rift basin formed by the oblique continental collision during the closure of the Paleozoic proto-Atlantic and a Late Triassic–Early Jurassic rift system created during the opening of the present Atlantic. Basement in the Gulf of Maine remained above sea level from the opening of the Atlantic 190 Ma (Early Jurassic) to the Eocene 55 Ma. That the Gulf of Maine remained a high for so long may have been due to igneous activity along the northwest-trending Boston–Ottawa Lineation extending from the vicinity of the St. Lawrence River, Canada to Gulf of Maine from Late Triassic to Early Cretaceous. The northwest-trending New England Seamounts south of Georges Bank may represent a seaward extension of this lineation. On Georges Bank, rising hundreds of meters above the Gulf of Maine, the basement exposed in the gulf is mantled by sediments thousands of meters thick. Included in these sediments are Early Jurassic- to earliest Cretaceous reefs along the continental slope and carbonates north of the reefs grading landward into continental sediments, Cretaceous–Cenozoic continental/marine terrigenous sediments and Pleistocene glacial deposits. The continental slope on the seaward flank of Georges Bank has a complex history of early to mid Mesozoic carbonate accretion, mid to late Mesozoic and Cenozoic calcareous/terrigenous sediments and canyon erosion, burial and exhumation going back to Early Cretaceous. 相似文献
20.
黑龙江东部中-新生代盆地演化 总被引：9，自引：2，他引：7
黑龙江省东部中-新生代盆地基底由佳木斯地块和完达山地体复合而成.佳木斯地块以加里东期变质岩及花岗岩为主,东缘发育晚古生代和早中生代大陆边缘沉积.完达山地体在中-晚侏罗世就位在佳木斯地块东缘,并在早白垩世早期逆冲到佳木斯地块之上,形成具有前陆盆地性质的大三江盆地.大三江盆地在早白垩世晚期遭受逆冲、走滑构造改造.敦密断裂以北的诸多盆地均属大三江盆地改造后的残余盆地.这些残余盆地和完达山地体之下可能存在隐伏的晚古生代和早中生代大陆边缘沉积.三江盆地东部是古近纪断陷的主要发育区,可能存在一与佳依地堑平行的深断陷.隐伏的大陆边缘沉积和断陷是值得重视的油气勘探领域. 相似文献