Active Motion of Tectonic Blocks in East Asia: Evidence from GPS Measurement

The relative Euler vectors of the Pacific, Philippine, Amurian, Okhotsk, N. Honshu and South China plates or blocks are deduced from earthquake slip vectors, transform fault azimuths and spreading rates, which are consistent with new results derived from the International Terrestrial Reference Frame ITRF2000 velocity field, the velocity field of GPS stations in China and the GPS measurement data of the GEONET network in Japan. Based on the two groups of Euler vectors, analysis and comparative study of the relative motions and deformations of the tectonic blocks in East Asia reveal the present-day motion characteristics of the blocks.     

Study on the plastic deformation and dynamic condition of Hatugou-Qingshuiquan-Gouli ductile shear zone in the eastern section of East KunlunEI北大核心CSCD

The Hatugou-Qingshuiquan-Gouli ductile shear zone recorded multiple cycles of orogeny in the eastern section of East Kunlun. The quartz c-axis fabric and microstructure of samples from the ductile shear zone were analyzed. We discussed the formation mechanism of subducted and crust extension-thinning of continental blocks in the eastern section of East Kunlun. Analysis results show that the deformation temperature of the ductile shear zone was between 380℃ and 650℃, which can be analogue with metamorphisms of middle-high greenschist facies to lower amphibolite facies. The differential stress and strain rate of the ductile shear zone are estimated at 173-509 MPa, 6.93×10-14-1.43×10-8 s-1, respectively, which suggest a possible origin of rapid subduction. Moreover, the deformation temperature, differential stress and strain increase toward the middle of East Kunlun fault zone, which is consistent with the fact that the middle part of the East Kunlun experienced the most intensive ductile shear deformation. The calculations of the kinematic vorticity values of the ductile shear belt show that the early transient kinematic vorticity (0.56-1.00) of ductile shear zone corresponds to the initial stage of the northward subducted southern parts of East Kunlun. In the middle to later stage, the kinematic vorticity (0.25-0.91) should correspond to the collision between southern and northern parts of East Kunlun. The latest C' instantaneous kinematic vorticity (0.19-0.51) corresponds to extensional stage in the post-orogenic setting. The quartz c-axis fabric and the structural characteristics show that the middle part of East Kunlun tectonic belt experienced at least 3 stages of tectonic movements, including the late Caledonian thrusting and left lateral strike slip shearing, the late Hercynian Indosinian thrusting and dextral strike slip shearing and the brittle ductile brittle-left lateral strike slip shearing in the early and later Yanshanian. ©, 2015, Science Press. All right reserved.     

Deep Tectonophysical Process of the Uplift of the Northern Qinghai--Tibet Plateau--Evidence from the Integrated Geological--Geophysical Profile from Golmud to the Tanggula Mountains, Qinghai Province, China

The tectonic activities occurring since the Cenozoic in the northern part of theQinghai-Tibet Plateau (the region from the East Kunlun Mountains to the Tanggula Mountains)were probably caused by the intense intraplate deformation propagation after the collision be-tween the Indian plate and the Eurasian plate. Their main expressions include the substantial up-lifting of the plateau, alternation of horizontal extension and compression under the verticalgreatest principal stress σ_1, occurrence of rift-type volcanic activity, formation of thebasin-range system, and successive eastward extrusion of blocks resulting from large-scalestrike-slip faulting. Geophysical exploration and experiments have revealed that there exist close-ly alternating horizontal high-velocity and low-velocity layers as well as lithospheric faults of aleft-lateral strike-slip sense in the lower part of the lithosphere (the lower crust and lithosphericmantle, 60-120 km deep). Based on an integrated study of the geological-geophysical data avail-able, the authors have proposed a model of deep-seated mantle diapir and the associatedtectonophysical process as the dynamic source for the uplift of the northern part of theQinghai-Tibet Plateau.     

3D Velocity Structure and Its Tectonic Implications in the East China Sea and Yellow Sea

3D structure of the crust and upper mantle in the studied area has been analyzed from surface wave tomography. The velocity distribution in the uppermost crust is symmetrical on two sides of the central line of the sea, and coincides with the structure of crystalline basement. The essential difference in tectonics between the East China Sea and the Yellow Sea mainly lies in that the velocity structures of their lower crust and upper mantle are identical to those of South China and North China respectively. In the upper mantle there exists a high-velocity zone with a nearly EW strike from the Hangzhou Bay, China, to the Tokara Channel, Japan, along about the latitude of 30°N. It is found that between the East China Sea and the Yellow Sea there are systematical differences in geomorphology, geology, seismicity, heat flow, quality factor and gravity and aeromagnetic anomalies, which is related to both left-lateral shear dislocation and right-lateral tear of the Benioff zone from the Hangzhou Bay to the Tokara Channel.It is inferred that the East China Sea was formed by Cenozoic back-arc extension. The boundary between the North China and South China crustal blocks stretches along the southern piedmont of Mts. Daba-Dabie-Hangzhou Bay-Tokara Channel, and the subduction zone at the Okinawa trench is the eastern boundary of the South China crustal block. The movements of the Pacific plate, Indian plate and upper mantle rather than the Philippine plate subduction have played a dominant role for the modern tectonic movements in East Asia.     

Late Paleoproterozoic Paleogeography of Baltica and Laurentia: New Paleomagnetic Data from 1.80–1.75 Ga Mafic Intrusions of Fennoscandia and Sarmatia

正Tectonic evolution and paleogeography of the two major continental blocks Fennoscandia and VolgoSarmatia during their docking to form the East European Craton(Baltica)at 1.8–1.7 Ga represent important‘puzzle     

Chinese Continental Blocks in Global Paleocontinental Reconstruction during Paleozoic and Mesozoic

The Cambrian to Cretaceous paleomagnetic data from Chinese continental and adjacent blocks were collected using principles to obtain reliable and high-precision paleomagnetic data and to pay attention to the similarity of paleobiogeography and the coordination of tectonic evolution. The Chinese continental blocks were laid up on the reconstruction of proposed global paleocontinents with almost the same scale. Thus, it can be clearly recognized that the global continents, including Chinese continental blocks, range along latitudes on the southern side of the equator during the Early Paleozoic. In the Paleozoic, Chinese continental blocks were still located among the Laurentia, Siberia and Gondwana plates, following the fast moving of the Siberia Plate northwards, the amalgamation in a north-south direction at the western parts of the Laurentia and Gondwana plates, and the Iapetus and Rheic Oceans were subducted, eventually to form a uniform Pangea in the Late Paleozoic. The Australian and Indian plates of Eastern Gondwana moved and dispersed gradually southwards, continued to extend the Paleo-Tethys Ocean. The Chinese continental and adjacent blocks were still located in the Paleo-Tethys Ocean, preserved the status of dispersion, gradually moving northwards, showing characteristics of ranging along a north–south orientation until the Permian. In addition, a series of local collisions happened during the Triassic, and consequently most of the Chinese continental blocks were amalgamated into the Pangea, except for the Gangdise and Himalayan blocks. There was a counter-clockwise rotation of the Eastern Asian continent in the Jurassic and northwards migration of the Chinese continent in varying degrees during the Cretaceous, but the Himalayan and Indian plates did not collide into the Chinese continent during this period.     

Discussion of the Relationships Between the Gondwana and Eastern China Block: Paleomagnetic Constraints

The time when Gondwana finally formed is still debatable (Powell and Pisarevsky, 2002; Meert, 2003). Paleomagnetic data have demonstrated that the appar-ent polar wander paths (APWPs) for the main conti-nental blocks of Gondwana are in good agreement from Early Cambrian to at least 260 Ma under the widely accepted Gondwana fit (see Li & Powell, 2001, Fig. 6). This is especially the case for Australia and Africa, of which APWPs are best defined and near identical. This indicates that the main amalgamation of East Gondwana and African blocks has likely com-pleted since the Early Cambrian.     

Cenozoic Exhumation History of the East Kunlun Orogenic Belt Constrained by Apatite Fission‐Track Thermochronology

正Objective The East Kunlun Orogenic belt constitutes the first marked change in the topographic reliefs north of the Qinghai-Tibet Plateau.The Cenozoic tectonic evolution of this orogenic belt is crucial for understanding the remote deformational effects of the Eurasian plate collision and the migration track at the northern margin of the plateau.However,when and how the uplift occurred remains     

Himalayan Tectonic Evolution in the East Asian Peri-Pacific Region

This paper summarizes the Late Palaeozoic. Indosinian and Yanshanian palaeotectonic settings in theperi-Pacific region of East Asia. On that basis, the Himalayan crustal movement in the region is divided intothe early and late tectonic stages and two principal tectonic phases. From the ocean to the continent, 5 giganticHimalayan formation-deformation belts are distinguished; they are the Northwest Pacific trench-island arcbelt. the Northwest Pacific marginal sea basin bell. the East China Sea-northern South China Seacontinental-shelf down-faulted belt. the East Asian epicontinental rift belt. and the East Asian intracontinentalrift belt. The Early and Late Himalayan tectonic evolution is dealt with. Finally the state of the Himalayan re-gional stress field and its evoution in the region are discussed. It is considered that the mechanism of their for-mation is closely related to the continent-ocean and surface-deep earth interaction.     

Jurassic Tectonic Revolution in China and New Interpretation of the “Yanshan Movement”

With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the “Yanshan Movement”. During the Mid-Late Jurassic （165±5 Ma）, great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the “East Asia convergent” tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic, followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano-magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the “Yanshan Movement”. In the paper, according to the deformation patterns, geodynamic settings and deep processes, the “Yanshan Movement” is redefined as the Late Jurassic East Asian multi-directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at -165±5 Ma. The substantial lithospheric attenuation in East China is considered the post-effect of the Yanshanian intracontinental orogeny and deformation.     

The Tectonic Implications of the Hongliuhe-Xichangjing Ophiolitic Mélanges Belt in the Central Region of the Beishan Orogen, NW China — Constrained by the U-Pb Ages of Detrital Zircons of the Metasandstones

The tectonic attributes of different blocks within orogenic belts are of great significance for the study of accretionary processes and the evolution of Earth. The Hongliuhe-Niujianzi-Baiyunshan-Xichangjing ophiolitic mélange belt(HXOMB) is distributed in the heart of the Beishan Orogen, the Shuangyingshan and Minshui-Hanshan blocks being distributed in the south and north of the HXOMB respectively, and a large number of Early Paleozoic geological units are exposed on the blocks. According to the zircon age populations of the metasandstones in the Baiyunshan area recovered in this paper, when compared with the zircon age populations of the Paleozoic metasandstones reported in the Niujuanzi and Hanshan areas, we found that the metasandstones of the Shuangyingshan Block have age peaks at c. 598 Ma, 742 Ma, 828 Ma, 941 Ma, 990 Ma, 1168 Ma, 1636 Ma, 2497 Ma with non-significant age populations of 1500–1300 Ma, showing a possible affinity with the Tarim Craton; the metasandstones of the Minshui-Hanshan Block have age peaks at c. 606 Ma, 758 Ma, 914 Ma, 1102 Ma, 1194 Ma, 1304 Ma, 1672 Ma with significant age populations of 1500-1300 Ma, showing a possible affinity with the Chinese Central Tianshan Block. Therefore, the HXOMB of the Beishan Orogen is of great significance in plate segmentation, which separates the Tarim Craton in the south and the Chinese Central Tianshan Block in the north. Based on the evolutionary process of the Hongliuhe-Xichangjing ocean in the Beishan Orogen, we believe that break-up and convergence can be recognized as having occurred twice between the Chinese Central Tianshan Block and the Tarim Craton since the Mesoproterozoic in the Beishan area. This was related firstly to the break-up of the Columbia Supercontinent and the convergence of the Rodinia Supercontinent, mainly during the Middle Mesoproterozoic to Early Neoproterozoic, and secondly to the opening and closing of the Hongliuhe-Xichangjing ocean, mainly during the Early Paleozoic.     

Intensification of the East Asian Monsoon in Southern China at about 300–400 kaBP Inferred from Eolian Deposits in the Middle-lower Reaches of the Yangtze River

In the East Asian monsoon region,eolian deposits widely distributed in the middle-lower reaches of the Yantgze River are among the best materials available for studies on Quaternary climate change in the subtropical zone of Southern China.Typical eolian deposits in this region include upper Xiashu Loess(XL) and underlying Vermiculated Red Soil(VRS) layers.In this paper,chronological and paleoclimatic studies are conducted on an eolian deposit sequence near Jiujiang(JJ) city in northern Jiangxi province.A magnetostratigraphic study,combined with optically stimulated luminescence(OSL) dating,is conducted on the JJ section and provides further evidence that eolian deposits in the middle-lower reaches of the Yangtze River have been formed since the late Early Pleistocene,and that the boundary age between the XL and VRS layers is about 300-400 kaBP.In grain-size records of the JJ section,the median grain-size and content of the 30 μm size fraction increase sharply after 300-400 kaBP,representing an East Asian winter monsoon intensification event.Further pollen analysis reveals differing pollen assemblages before and after 300-400 kaBP:there is an evident increase in plants adapted to grow in a warm humid environment after 300-400 kaBP,implying an increase in precipitation caused by intensification of the East Asian summer monsoon.Global ice volume and uplift of the Tibet Plateau(TP) are regarded as crucial factors influencing variations of the East Asian monsoon on a long-term scale.The deep-sea δ~(18)O record,which reflects variations in global ice volume,shows no obvious change after 300-400 kaBP.Moreover,the influence of global ice volume changes on the East Asian summer and winter monsoons is inverse;the global ice volume increase(decrease) implies a strengthened(weakened) winter monsoon and weakened(strengthened) summer monsoon.We therefore interpret the coupled intensifications of the East Asian summer and winter monsoons at about 300-400 kaBP to the uplift of the TP in the Middle Pleistocene.This climate event is also documented in eolian deposits from the southern margin of the Chinese Loess Plateau(CLP) and from the desert-loess transitional belt.However,it is not recorded in the loess-paleosol sequences from the central part of the CLP,thereby indicating differing climate responses to TP uplift in different regions,which requires further study.     

Thrust Propagation in the Aqqikkol Lake Area, the East Kunlun Mountains, Northwestern China

The western segment of the East Kunlun Mountains is one of the poorly studied regions in northwestern China. Through a structural analysis of the typical sections, we have the following views: (1) There is a very well developed fault system in the western segment of the East Kunlun Mountains and thrust propagation, normal slip and decoupling are the chief deformation events in this area. (2) Although the thrusting started in the Late Carboniferous and Late Triassic-Early Jurassic, strong activity took place in the Miocene-Quaternary when the Kumkol basin was strongly downwarped. (3) The tectonic pattern of coexistence of N-directed thrust propagation and S-directed normal slip in this area is consistent with the general tectonic pattern of the northern Qinghai-Tibet plateau and also very similar to that of the Himalayan region on the southern margin of the Qinghai-Tibet plateau, but their directions between the thrust propagation are opposite and all the strong thrust propagations occurred from the Mioc     

Research on the Terrane Tectonics in China

This paper summarizes the latest advances in research on the terrane tectonics of China.The terranes of China distributed around various plates may be divided into four terrane belts of different ages and sizes.i.e.,the East China,Northwest China,Southwest China and Qilling-Dabie terrane belts.Among them,the East China belt may be subdivided into three composite terrane groups;each terrane proup is composed of several terranes that were formed roughly at the same time and have distince geologic histories.The accretion of China‘s terranes involver three types;the collision type,the flake-thrusting type,and the docking type.The results of the lates study in the five widening fields and some advances in the methods of research on the terrane tectonics in China are presented in the present paper.     

Report on 34 Ga SHRIMP Zircon Age from the Yuntaishan Geopark in Jiaozuo, Henan Province

1 Introduction According to recent researches, the North China Craton consists of three parts: the eastern block, western block and central zone (Zhao, 2001; Wilde et al., 2002). Paleoarchean continental blocks and zircon residuals have only been found in a few regions, such as Anshan, East Liaoning (Liu et al., 1992; Song et al., 1996; Wan et al., 2002, 2005), Caozhuang, East Hebei (Liu et al., 1992) and Xinyang, West Henan (Zheng et al., 2004), which are mainly distributed in the east…     

The Characteristics of Migration of Ore Solutions in No.6 East Tin Deposit of the Songshujiao Orefield, Gejiu

No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.     

Study of the Early and Middle Triassic Lower Yangtze Sea Basin

The Early and Middle Triassic primary lower Yangtze sea basin was formed before the Yangtze and Sino. Korean blocks collided and were assembled. showing the characteristics of an open continental shelf.continental margin sea. In order to provide evidence useful for oil and gas exploration in the studied region, this paper centres on the features of the sediments and their facies framework in the basin and the sedimentation parameters such as the deposition rate, palaeotemperature, palaeosatinity, palaeodepth of water and palaeocurrents of the basin.     

Distribution of Palygorskite in the Lingtai Profile of Chinese Loess Plateau： Its Paleoclimatic Implications

Palygorskite is a typical indicator mineral of the arid and strong evaporation environment. Distribution of palygorskite in loess-red clay sequences may act as an important indicator for reconstruction of the paleoenvironment and paleoclimate.In this paper,field emission scanning electron microscope and high-resolution transmission electron microscope observations on the red clay-loess-paleosol of the Renjiapo profile at Lingtai,Gansu Province indicate that palygorskite occurs widely in red clay sequences formed before 3.6 Ma,but no occurrence has been found in eolian sediments since 3.2 Ma.Micromorphological features and microstructure of palygorskite show that it is an autogenic mineral formed during pedogenesis,and transformed from illite-montmorillonite under the pore water action.In the Lingtai profile,the disappearance horizon of palygorskite is consistent with those of increasing magnetic susceptibility,dust flux and depositional rate.The distribution of palygorskite in the profile indicates that the interval of around 3.6 Ma was an important transformation period of the East Asian paleomonsoon,when changes took place in the East Asia paleoclimate pattern,i.e.a high-frequency strong fluctuation alternative evolution of the environment. Therefore,palygorskite is a key indicator mineral of the East Asian paleomonsoon evolution of that time.     

Distribution of major hydrocarbon source rocks in the major oil-gas-bearing basins in China

The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Lieiliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.     

Distribution of Palygorskite in the Lingtai Profile of Chinese Loess Plateau: Its Paleoclimatic Implications

Palygorskite is a typical indicator mineral of the arid and strong evaporation environment. Distribution of palygorskite in loess-red clay sequences may act as an important indicator for reconstruction of the paleoenvironment and paleoclimate. In this paper, field emission scanning electron microscope and high-resolution transmission electron microscope observations on the red clay-loess-paleosol of the Renjiapo profile at Lingtai, Gansu Province indicate that palygorskite occurs widely in red clay sequences formed before 3.6 Ma, but no occurrence has been found in eolian sediments since 3.2 Ma. Micromorphological features and microstructure of palygorskite show that it is an autogenic mineral formed during pedogenesis, and transformed from iilite-montmorilionite under the pore water action. In the Lingtai profile, the disappearance horizon of palygorskite is consistent with those of increasing magnetic susceptibility, dust flux and depositional rate. The distribution of palygorskite in the profile indicates that the interval of around 3.6 Ma was an important transformation period of the East Asian paleomonsoon, when changes took place in the East Asia paleoclimate pattern, i.e. a high-frequency strong fluctuation alternative evolution of the environment. Therefore, palygorskite is a key indicator mineral of the East Asian paleomonsoon evolution of that time.