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1.
The paper discusses the velocity structure of the crust beneath the Crimean Mountains from the results of active and passive seismic experiments. Based on a new interpretation of seismic data from the old Sevastopol–Kerch DSS profile by modern full-wave seismic modeling methods, a velocity model of the crust beneath the Crimean Mountains has been constructed for the first time. This model shows the significant differences in the structure of two crustal blocks: (1) one characterized by higher velocities and located in the western and central Crimean Mountains, and (2) the other characterized by lower velocities and located in the east, in the Feodosiya–Kerch zone, which are subdivided by a basement uplift (Starokrymskoe Uplift). The former block is characterized by a more complex structure, with the Moho traced at depths of 43 and 55 km, forming two Moho discontinuities: the upper one corresponds to the platform stage, and the lower one, formed presumably at the Alpine stage of tectogenesis as a result of underthrusting of the East Black Sea microplate beneath the southern margin of the Scythian Plate in Crimea. At depths of 7–11 km, velocity inversion zone has been identified, indicating horizontal layering of the crust. Local seismic tomography using the data on weak earthquakes (mb ≤ 3) recorded by the Crimean seismological network allowed us to obtain data on the crustal structure beneath the Crimean Mountains at depths of 10–30 km. The crustal structure at these depths is characterized by the presence of several high-velocity crustal bodies in the vicinity of cities Yalta, Alushta, and Sudak, with earthquake hypocenters clustered within these bodies. Comparison of this velocity model of the Crimean Mountains with the seismicity distribution and with the results from reconstruction of paleo- and present-day stress fields from field tectonophysical study and earthquake focal mechanisms allowed the conclusion that the Crimean Mountains were formed as a result of on mature crust at the southern margin of the East European Platform and Scythian Plate, resulting from processes during various phases of Cimmerian and Alpine tectogenesis in the compressional and transpressional geodynamic settings. The collisional process is ongoing at the present-day stage, as supported by high seismicity and uplift of the Crimean Mountains. 相似文献
2.
In northwest Anatolia, there is a mosaic of different morpho-tectonic fragments within the western part of the right-lateral strike-slip North Anatolian Fault (NAF) Zone. These were developed from compressional and extensional tectonic regimes during the paleo- and neo-tectonic periods of Turkish orogenic history. A NE-SW-trending left-lateral strike-slip fault system (Adapazari-Karasu Fault) extends through the northern part of the Sakarya River Valley and began to develop within a N–S compressional tectonic regime which involved all of northern Anatolia during Middle Eocene to early Middle Miocene times. Since the end of Middle Miocene times, this fault system forms a border between a compressional tectonic regime in the eastern area eastwards from the northern part of the Sakarya River Valley, and an extensional tectonic regime in the Marmara region to the west. The extension caused the development of basins and ridges, and the incursions of the Mediterranean Sea into the site of the future Sea of Marmara since Late Miocene times. Following the initiation in late Middle Miocene times and the eastward propagation of extension along the western part of the NAF, a block (North Anatolian Block) began to form in the northern Anatolia region since the end of Pliocene times. The Adapazari-Karasu Fault constitutes the western boundary of this block which is bounded by the NAF in the south, the Northeast Anatolian Fault in the east, and the South Black Sea Thrust Fault in the north. The northeastward movement of the North Anatolian Block caused the formation of a marine connection between the Black Sea and the Aegean/Mediterranean Sea during the Pleistocene. 相似文献
3.
本文通过对中国东部海域地质地球物理资料进行综合分析,特别是近十年来海洋区域地质调查最新采集的地球物理资料,梳理了研究区基础地质特征,探讨了陆区大地构造单元在海区的延伸。研究表明:渤海和北黄海为典型的华北型基底并发育华北型沉积盖层;南黄海为典型的扬子型基底并发育扬子型沉积盖层;东海陆架为华夏型基底,东部很可能发育晚古生代沉积盖层,其上叠置了晚三叠世以来沉积盖层。下扬子地块西侧通过左旋走滑的郯庐断裂带,东侧通过右旋走滑的朝鲜西缘断裂带揳入华北地块中,朝鲜西缘断裂带兼具走滑和俯冲带性质。整个朝鲜半岛无论从变质基底和沉积盖层来看都类似于华北地块。扬子地块在北侧和东侧都发育“鳄鱼嘴”式构造,扬子地块的下地壳向北、向东俯冲于华北地块之下,而上地壳则仰冲于华北地块之上。江绍结合带表现为宽50~70 km的NE向高磁异常条带,进入杭州湾后走向转为近EW向,经舟山群岛、大衢山岛及附近岛屿,过东海陆架虎皮礁凸起向东进入日本九州岛。虎皮礁凸起的岩石很可能类似于大衢山岛,为一套俯冲增生杂岩。 相似文献
4.
The Philippine Sea Plate (PHS) simultaneously subducts northwestward and collides eastward with the Eurasian Plate (EU) in northeast Taiwan. These two tectonic events induce high seismic activity, which makes northeastern Taiwan one of the most seismically active zones in the world. To understand the mechanical processes at work, we used existing geophysical data and the aftershocks recorded following a recent large strike-slip event occurring within the PHS oceanic crust. During this event, a NW–SE trending left-lateral sub-parallel to the PHS/EU convergence vector was active. As a consequence of the collision/subduction plate geometry, we show that the lithosphere of the northwestern corner of the PHS has been torn in a NW–SE orientation. This tectonic feature is associated with an abrupt tectonic stress boundary and could generate large intra-plate earthquakes. 相似文献
5.
东海盆地处于西太平洋俯冲带前缘,是发育在华南克拉通基底之上的,以晚白垩世-新生代沉积为主的新生代盆地.东海盆地性质是在活动大陆边缘减薄陆壳之上的,由于洋-陆俯冲消减所引起的张裂、拉伸作用而形成的弧后裂谷型盆地,是西太平洋众多“沟-弧-盆”体系的一部分.东海盆地陆架外缘隆起控制着东海盆地的演化过程,该地质单元形成于晚白垩世,是陆缘隆起和增生楔的复合体,中新世后由于菲律宾海板块的活动而解体为现今的钓鱼岛隆褶带和琉球隆起.结合对陆架外缘隆起的研究后认为,东海盆地晚白垩世以来的演化历程具有3大构造阶段,即:第一阶段,古新世-中始新世西部坳陷形成发展期;第二阶段,中始新世-渐新世东部坳陷形成发展期,其中,中晚始新世太平洋板块的转向是东、西部坳陷构造迁移的分界点;第三阶段,中新世-全新世,东海盆地进入到菲律宾板块影响时期,原先的构造格局开始分解. 相似文献
6.
The Deep Geophysical Structure of the Middle Section of the Longmen Mountains Tectonic Belt and its Relation to the Wenchuan Earthquake 总被引：1，自引：0，他引：1
Investigation of the deep geophysical structure of the Longmen Mountains tectonic belt and its relation to the Wenchuan Earthquake is important for the study of earthquakes. By using magnetotelluric sounding profiles of the Luqu–Zhongjiang and Anxian–Suining; seismic sounding profiles of the Sichuan Maowen–Chongqing Gongtan, the Qinghai Huashi Gorge–Sichuan Jianyang, and the Batang–Zizhong; and magnetogravimetric data of the Longmen Mountains region, the deep geophysical structure of the Songpan–Ganzi block, the western Sichuan foreland basin, and the Longmen Mountains tectonic belt and their relation was discussed. The eastward extrusion of the Qinghai–Tibet Plateau thrusts the Songpan–Ganzi block upon the Yangtze block, which obstructs the eastward movement of the Qinghai–Tibet Plateau. The Maoxian–Wenchuan, Beichuan–Yingxiu, and Anxian–Guanxian faults of the Longmen Mountains fault belt dip to northwest with different dip angles and gradually converge in the deeper parts. Geophysical structure suggests that an intracrustal low-velocity, low-resistivity, and high-conductivity layer is common between the middle and upper crust west of the Longmen Mountains tectonic belt but not in the upper Yangtze block. The Sichuan Basin has a thick low-resistance sedimentary layer on a stable high-resistance basement; moreover, there are secondary paleohighs and depression structures at the lower part of the western Sichuan foreland basin with characteristic of high magnetic anomalies, whereas the Songpan–Ganzi block has a high resisitivity cover of upper crust and continues to a low-resistance layer. Considering the Longmen Mountains tectonic belt as the boundary, there are Bouguer gravity anomalies of "one belt between two zones." Thus, we infer that there is a corresponding relation between the inferred crystalline basement of the Songpan block and the underlying basin basement of the Longmen Mountains fault belt. Furthermore, there may be an extensive ancient Yangtze block, which is west of the Ruoergai block. In addition, the crust–mantle ductile shear zone under the Longmen Mountains tectonic belt is the main fault, whereas the Beichuan–Yingxiu and Anxian–Guanxian faults at the surface are earthquake faults. The Wenchuan Ms 8.0 earthquake might be attributed to the collision of the Yangtze block and the Qinghai–Tibet Plateau. The eastward obduction of the eastern edge of the Qinghai–Tibet Plateau and eastward subduction of its deeper part under the influence of the collision of the Indian, Pacific, and Philippine Plates with the Eurasia Plate might have caused the Longmen Mountains tectonic belt to cut the Moho and extend to the middle and upper crust; thus, creating high stress concentration and rapid energy release zone. 相似文献
7.
Christina Widiwijayanti Christel Tiberi Christine Deplus Michel Diament Valentin Mikhailov Rmy Louat 《Tectonophysics》2004,386(3-4):203-222
In order to better understand the tectonic framework of the Northern Molucca Sea area, we inverted satellite and sea-surface gravity data into an iterative scheme including a priori seismological and geological data. The resulting 3-D density model images the various tectonic units from the surface down to 40 km. We proceed to various tests to assess the stability and robustness of our inversion. In particular, we performed an offset and average smoothing method to properly refine our results. The resulting model shows a striking vertical regularity of the structures through the different layers, whereas the density contrasts appear strongly uneven in the horizontal direction.The density model emphasizes the complexity of the upper lithospheric structure in the northern Molucca Sea, which is clearly dominated by the interaction between ophiolitic ridges, sedimentary wedges and rigid blocks of the Philippine Sea Plate. It also provides new, hard information that can be used in discussion of the evolution of the region.Large density variations are concentrated in the central part of northern Molucca Sea and dominate the upper lithospheric. North–south trending density structures along the Central Ridge and west dipping thrust faults on the western side of the region are clearly imaged. In the eastern part of the region, we distinguish several blocks, especially the Snellius Plateau which seems to be split into two parts. We interpret this as an oceanic plateau associated with thicker crust that previously belonged to the Philippine Sea Plate. This crust is now trapped between the Molucca Sea complex collision zone and the Philippine Trench, due to the development of a new subduction zone in its eastern side. 相似文献
8.
东昆仑山南缘大型转换挤压构造带和斜向俯冲作用 总被引：28，自引：5，他引：23
东昆仑地体和巴颜喀拉－－松潘甘孜地体之间的会聚边界是一条位于东昆仑南缘的大型转换挤压构造带。研究表明该带的东段（阿尼玛卿段）和西段（东－西大滩段）构造特征不同,阿尼玛卿段的构造以印支期具往南西造山极性的逆冲叠覆岩片和新生代脆性左行走滑构造为特征,东－西大滩段是由220Ma形成的EW向韧性左行走滑剪切带及两则伴生的挤压褶皱断裂带组成,韧性变形持续至20Ma,之后表现为脆性左行走滑构造再活动。因此,东昆仑南缘大型会聚带是一条由东段的“收缩挤压”为主向西段的“转换挤压”逐渐过度的特殊复杂的构造带,它的形成与巴颜喀拉－－松潘甘孜地体往NE方向斜向俯冲于东昆仑地体之下有关。 相似文献
9.
The paper considers the morphology, deep structure, and geodynamic features of the Ural–Herirud postorogenic strike-slip fault (UH fault), along which the Moho (the “M”) shifts along the entire axial zone of the Ural Orogen, then further to the south across the Scythian–Turan Plate to the Herirud sublatitudinal fault in Afghanistan. The postcollisional character of dextral displacements along the Ural–Herirud fault and its Triassic–Jurassic age are proven. We have estimated the scale of displacements and made an attempt to make a paleoreconstruction, illustrating the relationship between the Variscides of the Urals and the Tien Shan before tectonic displacements. The analysis of new data includes the latest generation of 1: 200000 geological maps and the regional seismic profiling data obtained in the most elevated part of the Urals (from the seismic profile of the Middle Urals in the north to the Uralseis seismic profile in the south), as well as within the sedimentary cover of the Turan Plate, from Mugodzhary to the southern boundaries of the former water area of the Aral Sea. General typomorphic signs of transcontinental strike-slip fault systems are considered and the structural model of the Ural–Herirud postcollisional strike-slip fault is presented. 相似文献
10.
The eastern margin of the Qaidam Basin lies in the key tectonic location connecting the Qinling, Qilian and East Kunlun orogens. The paper presents an investigation and analysis of the geologic structures of the area and LA-ICP MS zircon U-Pb dating of Paleozoic and Mesozoic magmatisms of granitoids in the basement of the eastern Qaidam Basin on the basis of 16 granitoid samples collected from the South Qilian Mountains, the Qaidam Basin basement and the East Kunlun Mountains. According to the results in this paper, the basement of the basin, from the northern margin of the Qaidam Basin to the East Kunlun Mountains, has experienced at least three periods of intrusive activities of granitoids since the Early Paleozoic, i.e. the magmatisms occurring in the Late Cambrian (493.1±4.9 Ma), the Silurian (422.9±8.0 Ma-420.4±4.6 Ma) and the Late Permian-Middle Triassic (257.8±4.0 Ma-228.8±1.5 Ma), respectively. Among them, the Late Permian - Middle Triassic granitoids form the main components of the basement of the basin. The statistics of dated zircons in this paper shows the intrusive magmatic activities in the basement of the basin have three peak ages of 244 Ma (main), 418 Ma, and 493 Ma respectively. The dating results reveal that the Early Paleozoic magmatism of granitoids mainly occurred on the northern margin of the Qaidam Basin and the southern margin of the Qilian Mountains, with only weak indications in the East Kunlun Mountains. However, the distribution of Permo-Triassic (P-T) granitoids occupied across the whole basement of the eastern Qaidam Basin from the southern margin of the Qilian Mountains to the East Kunlun Mountains. An integrated analysis of the age distribution of P-T granitoids in the Qaidam Basin and its surrounding mountains shows that the earliest P-T magmatism (293.6-270 Ma) occurred in the northwestern part of the basin and expanded eastwards and southwards, resulting in the P-T intrusive magmatism that ran through the whole basin basement. As the Cenozoic basement thrust system developed in the eastern Qaidam Basin, the nearly N-S-trending shortening and deformation in the basement of the basin tended to intensify from west to east, which went contrary to the distribution trend of N-S-trending shortening and deformation in the Cenozoic cover of the basin, reflecting that there was a transformation of shortening and thickening of Cenozoic crust between the eastern and western parts of the Qaidam Basin, i.e., the crustal shortening of eastern Qaidam was dominated by the basement deformation (triggered at the middle and lower crust), whereas that of western Qaidam was mainly by folding and thrusting of the sedimentary cover (the upper crust). 相似文献
11.
The Dead Sea Basin is a morphotectonic depression along the Dead Sea Transform. Its structure can be described as a deep rhomb-graben (pull-apart) flanked by two block-faulted marginal zones. We have studied the recent tectonic structure of the northwestern margin of the Dead Sea Basin in the area where the northern strike-slip master fault enters the basin and approaches the western marginal zone (Western Boundary Fault). For this purpose, we have analyzed 3.5-kHz seismic reflection profiles obtained from the northwestern corner of the Dead Sea. The seismic profiles give insight into the recent tectonic deformation of the northwestern margin of the Dead Sea Basin. A series of 11 seismic profiles are presented and described. Although several deformation features can be explained in terms of gravity tectonics, it is suggested that the occurrence of strike-slip in this part of the Dead Sea Basin is most likely. Seismic sections reveal a narrow zone of intensely deformed strata. This zone gradually merges into a zone marked by a newly discovered tectonic depression, the Qumran Basin. It is speculated that both structural zones originate from strike-slip along right-bending faults that splay-off from the Jordan Fault, the strike-slip master fault that delimits the active Dead Sea rhomb-graben on the west. Fault interaction between the strike-slip master fault and the normal faults bounding the transform valley seems the most plausible explanation for the origin of the right-bending splays. We suggest that the observed southward widening of the Dead Sea Basin possibly results from the successive formation of secondary right-bending splays to the north, as the active depocenter of the Dead Sea Basin migrates northward with time. 相似文献
12.
The characteristics of the Bolokenu-Aqikekuduk (Bo-A) fault, a right-lateral strike-slip fault
that runs for more than 700 km long and obliquely cuts North Tianshan Mountains, are evaluated here
based on remote sensing data, and through an analysis of the results from field investigations as well
as climate-geomorphic events.
The fault is composed of a western segment with a NW strike and an eastern segment with a NWW
strike. The western segment is nearly 250 km long, extending northwestward into Kazakhstan with
a right-lateral strike-slip rate of 5 mm/a. This domain consists of 4e5 rupture sections, with 3e4 deformation
belts, caused by ancient or historical earthquakes, and suggesting the potential for the occurrence
of further strong earthquakes (with M z 7.5) in future.
The eastern segment of the fault shows a right-lateral strike-slip rate of 1e1.4 mm/a, with the development
of 3e4 deformation belts caused by ancient or historical earthquakes, and with a potential for
future strong earthquake with M z 7.0. A typical strain partitioning style in the compression area has developed between the intermontane Bo-
A fault and the piedmont thrust structures of Northern Tianshan Mountains, under the effect of oblique
compression, as indicated by the piedmont thrust structure and the strike-slip fault in the mountains. 相似文献
13.
Plate tectonic evolution of the southern margin of Eurasia in the Mesozoic and Cenozoic 总被引：4，自引：0，他引：4
Thirteen time interval maps were constructed, which depict the Triassic to Neogene plate tectonic configuration, paleogeography and general lithofacies of the southern margin of Eurasia. The aim of this paper is to provide an outline of the geodynamic evolution and position of the major tectonic elements of the area within a global framework. The Hercynian Orogeny was completed by the collision of Gondwana and Laurussia, whereas the Tethys Ocean formed the embayment between the Eurasian and Gondwanian branches of Pangea. During Late Triassic–Early Jurassic times, several microplates were sutured to the Eurasian margin, closing the Paleotethys Ocean. A Jurassic–Cretaceous north-dipping subduction boundary was developed along this new continental margin south of the Pontides, Transcaucasus and Iranian plates. The subduction zone trench-pulling effect caused rifting, creating the back-arc basin of the Greater Caucasus–proto South Caspian Sea, which achieved its maximum width during the Late Cretaceous. In the western Tethys, separation of Eurasia from Gondwana resulted in the formation of the Ligurian–Penninic–Pieniny–Magura Ocean (Alpine Tethys) as an extension of Middle Atlantic system and a part of the Pangean breakup tectonic system. During Late Jurassic–Early Cretaceous times, the Outer Carpathian rift developed. The opening of the western Black Sea occurred by rifting and drifting of the western–central Pontides away from the Moesian and Scythian platforms of Eurasia during the Early Cretaceous–Cenomanian. The latest Cretaceous–Paleogene was the time of the closure of the Ligurian–Pieniny Ocean. Adria–Alcapa terranes continued their northward movement during Eocene–Early Miocene times. Their oblique collision with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and its foreland basin. The formation of the West Carpathian thrusts was completed by the Miocene. The thrust front was still propagating eastwards in the eastern Carpathians.During the Late Cretaceous, the Lesser Caucasus, Sanandaj–Sirjan and Makran plates were sutured to the Iranian–Afghanistan plates in the Caucasus–Caspian Sea area. A north-dipping subduction zone jumped during Paleogene to the Scythian–Turan Platform. The Shatski terrane moved northward, closing the Greater Caucasus Basin and opening the eastern Black Sea. The South Caspian underwent reorganization during Oligocene–Neogene times. The southwestern part of the South Caspian Basin was reopened, while the northwestern part was gradually reduced in size. The collision of India and the Lut plate with Eurasia caused the deformation of Central Asia and created a system of NW–SE wrench faults. The remnants of Jurassic–Cretaceous back-arc systems, oceanic and attenuated crust, as well as Tertiary oceanic and attenuated crust were locked between adjacent continental plates and orogenic systems. 相似文献
14.
The paper presents new data on seismotectonic studies along the Adygei profile in the western part of the Central Caucasus and provides an overview of deep geophysical studies of the Greater Caucasus. For the first time, comprehensive geophysical characteristics of a crustal section of the Greater Caucasus across an orogenic structure (along the Adygei profile) have been obtained with a uniform step of observations. Based on factual data obtained by such methods as converted waves from distant earthquakes, magnetotelluric sounding, and gravimagnetic surveys, sinking of the marginal part of the southern microplate into the mantle is verified. It is noted that the contemporary Alpine structure of the Greater Caucasus formed during gentle thrusting of the Earth’s crust (Scythian Plate) from the north on the consolidated crust of the southern microplate. 相似文献
15.
西沙海域夹持于南海西北次海盆和西南次海盆之间,构造演化过程与南海的扩张和南海西部的走滑作用关系密切.基于覆盖西沙海域的区域地震资料开展了构造—地层解释、盆地结构特征分析和区域构造演化制图,整体上将西沙海域划分出3种类型盆地,即高角度断层控制的盆地、低角度拆离断层控制的盆地和走滑盆地.结合地壳厚度变化和伸展薄化程度,突出断层的构造样式,将西沙海域划分为北部拆离断层构造发育区、东南部拆离断层构造发育区、西部走滑断层发育区和中部高角度断层发育区,进而明确了西沙海域盆地的基本构造格局.同时,以关键构造界面为主线,强调了不同类型断层在岩石圈地壳减薄过程中的作用,阐明了西沙海域盆地的差异构造演化过程. 相似文献
16.
珠江口盆地位于太平洋俯冲的东部动力系统、印度?澳大利亚板块与欧亚碰撞或新特提斯洋俯冲的西部动力系统相互作用的中间地带,因此其构造成因及南海海盆打开机制一直存在争论;且构造对南海北部陆缘盆地群的油气成藏有何作用也不甚清晰.本专辑以珠江口盆地为例,特别是以阳江东凹为精细解剖区,结合中国东部新生代盆地的研究成果,展开了以下问... 相似文献
17.
S. L. Kostyuchenko A. F. Morozov R. A. Stephenson L. N. Solodilov A. G. Vedrentsev K. E. Popolitov A. F. Aleshina V. S. Vishnevskaya T. P. Yegorova 《Tectonophysics》2004,381(1-4):101
This paper presents an integrated geophysical study of the southern margin of the East European Craton (EEC) in the Karpinksy Swell-North Caucasus area. It presents new interpretations of deep refraction and wide-angle reflection “deep seismic sounding” (DSS) data as well as conventional seismic and CDP profiling and new analyses of potential field data, including three-dimensional gravity and magnetic modelling. An integrated model of the physical properties and structure of the Earth's crust and, partially, upper mantle displays distinct features that are related to tectonic history of the study area. The Voronezh Massif (VM), the Ukrainian Shield and Rostov Dome (RD) of the EEC as well as the Donbas Foldbelt (DF), Karpinsky Swell (KS), Scythian Plate (SP) and Precaspian Basin (PCB) constitute the geodynamic ensemble that developed on the southern margin of the continent Baltica. There proposed evolutionary model comprises a stage of rifting during the middle to late Devonian, post-rift extension and subsidence during Carboniferous–early Permian times (synchronous with and related to the southward displacement of the Rostov Dome and extension in a palaeo-Scythian back-arc basin), and subsequent Mesozoic and younger evolution. A pre-Ordovician, possibly Riphean (?), mafic magmatic complex is inferred on a near vertical reflection seismic cross-section through the western portion of the Astrakhan Dome in the southwest part of the Precaspian Basin. This complex combined with evidence of a subducting slab in the upper mantle imply the presence of pre-Ordovician (Riphean?) island arc, with synchronous extension in a Precaspian back-arc basin is suggested. A middle Palaeozoic back-arc basin ensemble in what is now the western Karpinsky Swell was more than 100 km to the south from its present location. The Stavropol High migrated northwards, dislocating and moving fragments of this back-arc basin sometime thereafter. Linear positive magnetic anomalies reflect the position of associated faults, which define the location of the eastern segment of the Karpinsky Swell. These faults, which dip northward, are recognised on crustal DSS profiles crossing the Donbas Foldbelt and Scythian Plate. They are interpreted in terms of compressional tectonics younger than the Hercynian stage of evolution (i.e., post-Palaeozoic). 相似文献
18.
东昆仑东段深大断裂的新认识 总被引：5，自引：1，他引：5
青海东昆仑东段在地质上已划定有东昆中、东昆南、东昆北、布青山南缘、温泉-哇洪山等多条深大断裂构造.以东昆仑东段开展的10个图幅1:20万区域重力调查成果--布格重力异常为基础,依据窗口平均法、水平导数等数据处理方法提取的区域场及剩余场等丰富的重力异常信息,结合航磁异常等资料,对东昆中、东昆北等断裂构造的展布位置提出了新的看法,并根据重力资料新推断断裂构造12条,提出尖山-哈莉哈德山断裂为2个一级构造单元的分界,同时通过拟合布格重力异常长剖面的定量计算方法,获取了部分深大断裂构造在东昆仑东段的产状参数. 相似文献
19.
A geological density section of the Deryugin Basin (western part of the Sea of Okhotsk) was studied along the profile Sakhalin Island-Deryugin Basin-Central Okhotsk Rise. The investigations were conducted by the method of gravity modeling, which allowed us to trace the density variations of the Earth’s crust layers along the lateral. The horizontal density stratification of the Earth’s crust layers was found, which assumes a stratified-block model of its structure. The established density structure of the Earth’s crust showed that the Deryugin Basin is located in the junction zone between the Sakhalin-Hokkaido microplate and the Okhotsk Sea Plate separated by a structural suture. The western and eastern edges of the basin belong to the aforementioned plates, respectively. It was assumed that accumulations of various mineral associations are confined to the suture zone, while the “granite” layer (basement) of the Deryugin trough walls in the western edge of the Deryugin Basin presumably contains secondary reservoirs of hydrocarbons. 相似文献
20.
R. D. Müller K. Gohl S. C. Cande A. Goncharov A. V. Golynsky 《Australian Journal of Earth Sciences》2013,60(8):1033-1045
Tectonic models for the Late Cretaceous/Tertiary evolution of the West Antarctic Rift System range from hundreds of kilometres of extension to negligible strike-slip displacement and are based on a variety of observations, as well as kinematic and geodynamic models. Most data constraining these models originate from the Ross Sea/Adare Trough area and the Transantarctic Mountains. We use a new Antarctic continental crustal-thinning grid, combined with a revised plate-kinematic model based on East Antarctic – Australia – Pacific – West Antarctic plate circuit closure, to trace the geometry and extensional style of the Eocene – Oligocene West Antarctic Rift from the Ross Sea to the South Shetland Trench. The combined data suggest that from chron 21 (48 Ma) to chron 8 (26 Ma), the West Antarctic Rift System was characterised by extension in the west to dextral strike-slip in the east, where it was connected to the Pacific – Phoenix – East Antarctic triple junction via the Byrd Subglacial Basin and the Bentley Subglacial Trench, interpreted as pullapart basins. Seismic-reflection profiles crossing the De Gerlache Gravity Anomaly, a tectonic scar from a former spreading ridge jump in the Bellingshausen Sea, suggest Late Tertiary reactivation in a dextral strike-slip mode. This is supported by seismic-reflection profiles crossing the De Gerlache Gravity Anomaly in the Bellingshausen Sea, which show incised narrow sediment troughs and vertical faults indicating strike-slip movement along a north – south direction. Using pre-48 Ma plate circuit closure, we test the hypothesis that the Lord Howe Rise was attached to the Pacific Plate during the opening of the Tasman Sea. We show that this plate geometry may be plausible at least between 74 and 48 Ma, but further work especially on Australian – Antarctic relative plate motions is required to test this hypothesis. 相似文献