The Qinghai—Tibet plateau and its surrounding areas including Indian subcontinent, Xinjiang, Mongolia, is a largest lithosphere convergence place in the world, which characterized by continent\|continent collision wi...The Qinghai—Tibet plateau and its surrounding areas including Indian subcontinent, Xinjiang, Mongolia, is a largest lithosphere convergence place in the world, which characterized by continent\|continent collision with a thick crust and lithosphere. The high resolution seismic surface wave tomographic inversion has been conducted for studying the 3D velocity structure of crust and upper mantle in those areas. The seismic surface waveform data are from the archives of the CDSN, GSN and GEOSCOPE. About 2400 long period surface waveform recordings are available for both dispersion and waveform tomographic inversion. The block inversion by grid 1°×1°in Qinghai—Tibet plateau and 2°×2°in the surrounding areas were adapted. The resulting maps show the high resolution 3D shear wave velocity variation from earth’s surface to 400km depth.展开更多
Located in the northern margin of the Qinghai—Tibet Plateau, the Longshoushan Mt. is a small block between Qinghai—Tibet Landmass and Alashan Landmass.Traditional tectonic viewpoint does not consider that the Longsh...Located in the northern margin of the Qinghai—Tibet Plateau, the Longshoushan Mt. is a small block between Qinghai—Tibet Landmass and Alashan Landmass.Traditional tectonic viewpoint does not consider that the Longshoushan Mt. is a single tectonic block. It is quite evident that there is only a hazy idea about the Longshoushan block. Though there is a very complex tectonic region between Qinghai—Tibet Landmass and Alashan Landmass, the Longshoushan block in the region shows unique tectonic landforms, deep structures and uplift mechanisms. Researching into the relationship between the Longshoushan block and the Qinghai—Tibet and Alashan Landmasses will contribute to the realization of boundary and orogenic belt on the northern margin of the Qinghai—Tibet block. It is a very important scientific subject.The Longshoushan Mt., longer than 150km in NWW direction and wider than 10km, is located on the northern side of Hexi corridor(100 5°～102 5°E,38 5°～39 3°N). It extends from the northwest of Zhangye to Hexibu, and from the south of Chaoshui basin to the north of Minle basin. From west to east, there are the highest peak, Dongdashan Mt.(3616m), the second peak, Dufengding(2937m) and Qianshan peak(2827m), height of the mountains is getting lower and lower, mean height above sea level is over 2000m, and relative height difference is about 1000m. The Longshoushan Mt. provides a natural defence for stopping the southward migration of sandstorm in the Hexi corridor, and forms a topographic step zone from the Alashan Plateau to the Qinghai—Tibet Plateau. In the Longshoushan area, developed landforms, such as planation surface, table\|land, terrace land, are general characters of all geomorphic units. It is shown that the Longshoushan Mt. is a intermittently uplifted block. An astonishingly similar of geometric patterns of Taohualashan Mt. and Hongshihu basin is very interesting natural landscape in the area. It is suggested that Taohualashan Mt. broke away from Hongshihu Basin in secular tectonic movement. The viewpoint is supported by major formation, lithofacies, limitation and style of active faulting. The Longshoushan block consists of two major active fault zones (the northern Longshoushan fault zone and the southern Longshoushan fault zone), the active Pingshanhu—Hongshihu fault basin belt and Taohualashan—Xieposhan tectonic uplift belt. In addition, there are the NNW\|trending West Polamading fault, NWW\|trending Maohudong fault trough, NNE\|trending Daxiahe rift valley and others on the block. the activity and formation style of these structures indicate that the block is acted not only by compressive stress, but also by tensile stress. The northern Longshoushan and southern Longshoushan fault zones are closely related to formation and evolution of the Longshoushan block, the two zones are active fault zones since late Pleistocene and boundary fault zones of the block. The genesis and activity style of the Pingshanhu\|Hongshihu basin are similar to the continental rift, which may be due to the mantle uplift.展开更多
Finite strain patterns of rocks The structural styles and crustal shortening in the northern margin of Qinghai—Tibet plateau are examined by systematic finite strain measurements. The finite strain patterns in this a...Finite strain patterns of rocks The structural styles and crustal shortening in the northern margin of Qinghai—Tibet plateau are examined by systematic finite strain measurements. The finite strain patterns in this area are of following characteristics:① The orientation of & principal axes of strain ellipsoid varies regularly in regard to different tectonic locations. In fact, most of the measured X axes are parallel to the regional structure lines, striking east\|west or approximately east\|west with some X axes trending northeast\|southwest. The measured Z\|axes are approximately at right angle to the regional structure lines, trending north\|northeast or north\|northwest.② The Flinn parameter k is higher in the northern and southern margins of the basin than that in the basin center, indicating that the margins of basin experienced extensional strain and the middle of basin undergo strain.③ Rocks of different age possess different strain state and show k value of 1～2 for Tertiary rocks, 3～4 for Jurassic—Cretaceous rocks. The k value of the basement rocks is the highest of all.展开更多
Recently, this study group established “the map of MOHO\|surface bathymetric line in Chinese and Near Region" on the basis of latest survey and study of the crustal depth, the preliminary result shows that the r...Recently, this study group established “the map of MOHO\|surface bathymetric line in Chinese and Near Region" on the basis of latest survey and study of the crustal depth, the preliminary result shows that the regular meridional and latitudinal upwarping and downwarping structural pattern of MOHO\|surface bathymetric line among Eurasian plate and Pacific plate and the Indian plate alternately appears, and which is accreted and coupled with basin ridge structure that exist shallow crustal base, continental crust and oceanic crust and others regular upwarping and downwarping net structure system that possessing different block characters and different scales exist together. Among different structure systems, it occurs that ramp downwarping impetus transform structure belts whose trends is characteristic. Nowadays upwarping and downwarping net structure system is basically modeled in Himalayan orogeny period. It is showed that the Earth revolution way has been changed in this period, which leaded to a new Earth dynamics cycle.The pattern of upwarping and downwarping structure among different structure systems or different structure blocks , and the characters of different trends and different scale transform structure belts, reflects the structure movement way and their conversion law, and reveals the Earth centralized dynamics mechanics that is produced by the revolutionary effect under the environments of aster system. This can be clearly reflected by the change of impetus way between Qinghai—Tibet highland structure system and near structure system.展开更多
The Northeastern margin of Qinghai—Tibet plateau,here refers to the region bounded by Western Qinling fault zone and Longshoushan—Liupanshan tectonic zone, where obliquely compression deformation occurred with the N...The Northeastern margin of Qinghai—Tibet plateau,here refers to the region bounded by Western Qinling fault zone and Longshoushan—Liupanshan tectonic zone, where obliquely compression deformation occurred with the NE\|trending maximum principle axis of stress, with Ordos Massif to the east, Alaxa Block to the north, and Qinghai—Tibet plateau to the southwest. The main structure in this region is Haiyuan—Gulang transpression zone. It consists of a series of active faults: the Haiyuan fault zone, the Tianjingshan fault zone, the Yantongshan fault zone and the Niushoushan—Luoshan fault zone.展开更多
Based on the studies of geology and geochemistry, A’nymaque—Mianlue limited oceanic basin is comparable to the Paleo\|Tethys on time, sedimentary, biocoenosis, and the type of ophiolite (Coleman, 1984; Deng, 1984; X...Based on the studies of geology and geochemistry, A’nymaque—Mianlue limited oceanic basin is comparable to the Paleo\|Tethys on time, sedimentary, biocoenosis, and the type of ophiolite (Coleman, 1984; Deng, 1984; Xu, 1996;Chenliang, 1999). The A’nyemaqen—Mianlue oceanic basin was one of a northeast branches of Paleo\|Tethys (Zhang Guowei, 1995; 1996) .Our researches on deformations reveal that tectonic styles of the Southwest Qinling orogenic belt is obviously influenced by the dynamics of Qinghai—Tibet plateau.Structural deformation analysis suggested that the southwest part of Qinling have undergone 3 major deformation stages in Mesozoic and Cenozoic. Firstly, rock folding at deep\|middle tectonic level and progressively thrusting shearing characterized the deformation of collision. The thrust tectonics are south\|directed, such as A’nymaque, Wenxian—Kangxian and Mianlue thrusting systems, and the deformations took place in T\-2—T\-3. Secondly, the middle\|tectonic level thrusting and sinistral strike\|slip formed at early intracontinental period (J—K), the thrust tectonics was south\|directed and the regional penetrative left\|lateral slips were NW or NWW. Finally, the east\|west extensional deformations which occurred in late Mesozoic and Cenozoic, a series of north\|south directing basins came into being in this stage, Huixian—Chengxian basin and Lixian basin for example, which overlapped the former deformation styles.展开更多
The uplift history has been becoming the key for the geological science of Qinghai—Tibet plateau. The scholars abroad have reconstructed uplift history of the plateau by studying geological process of the inner globe...The uplift history has been becoming the key for the geological science of Qinghai—Tibet plateau. The scholars abroad have reconstructed uplift history of the plateau by studying geological process of the inner globe, they considered that the altitude of the plateau got up to the maximum at 14Ma (M.Coleman et al, 1995; S.Turner et al, 1993)or the plateau got to the present elevation at about 8Ma (T.M.Harrison,1992). The Chinese geologists make use of substitutes of outer environmental elements to deduce that the uplift of Qinghai—Tibet plateau began from 3 4Ma(Li Jijun,1995). It is obvious that there are the different views and controversies about the plateau uplift history.展开更多
The scientific research on Qinghai—Tibet Plateau has already been the hot and key point on the plateau evolvement, the earth ecological variety, as well as the society harmonious development. The research on Qinghai...The scientific research on Qinghai—Tibet Plateau has already been the hot and key point on the plateau evolvement, the earth ecological variety, as well as the society harmonious development. The research on Qinghai—Tibet Plateau has the following characteristics:(1) 4\|dimension of time and space: with a vast territory and very deep depth, as well as the big time span.(2) Wide fields and across subjects: including geology, environment, ecology, climate, land, agriculture, forestry, animal husbandry, etc.(3) Theory and practice with profound and lasting influence: the research results can be great function for the direction in understanding the world, ecological environment and the human living conditions.The current issues of the research on Qinghai—Tibet Plateau are as follows:(1) Thousands of papers concerned about Qinghai—Tibet Plateau are lack of quantification data, and the research results are not displayed vividly.(2) The study scopes are more in the portion and less in the whole.(3) There are not enough work of combination of depth study with surface study, the representation in 3\|D is limited.(4) The study of time variation is not enough and there is poor way to show the time series results.(5) There are not enough work in the different specialties intercross, as well as the synthesis study of interdisciplinary subjects and cross subjects.展开更多
The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basi...The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basin above 2300m ASL.The basin has deposited different kinds of sediments with 1600m in depth. The early Tertiary strata were first named as Lijiang formation in 1961, and later named as Hongyanzi formation. The later Tertiary strata, the lignite\|bearing strata, were once named as Xigeda formation. Li Yougheng(1978) found some mammal fossils in the strata, so they named it Yanyuan formation. The Hongyanzi Formation which thickness is 1022m can be divided into five members according to the lithologic characters. The first one is mainly made of purplish\|red coarse conglomerates. The composition of gravel mainly consists of limestone and purplish\|red sandstone and marl. The second one consists of sandstone interbedded with conglomerate. The member has three cyclic sequences from conglomerate to sandstone. The composition of gravel of this member is mainly limestone. From bottom to top the degree of sorting and roundness tends to be well. In sandstones or sand lenticules the oblique bedding and trough cross\|bedding can be seen. The third one is the member of sandstone and mudstone. The sandstone is light purple while the mudstone is purplish red. Ripple marks can be seen in the sandstone. The forth one consists of conglomerate interbedded with mudstone, The conglomerate and the sandstone assume three cyclic sequences. The composition of the gravel is chiefly limestone. The fifth one is a member of light purple massive conglomerate. The composition of the gravel is limestone. The imbricate structure can be seen in the conglomerate. The strata belong to later Eocene epoch in accordance with the fossils of mammals, plants and ostracoda in it.展开更多
A geophysical survey including Magnetotelluric sounding(MT), gravity and geomagnetism was carried out in eastern region of Qinghai—Tibet plateau in 1998. It is to be known from tectonic map that study area was divide...A geophysical survey including Magnetotelluric sounding(MT), gravity and geomagnetism was carried out in eastern region of Qinghai—Tibet plateau in 1998. It is to be known from tectonic map that study area was divided into four blocks by three large sutures, but we have very little information on deep\|seated structure which have close relationship with evolution of Tibet plateau, our purpose is to find some deep crustal structure evidences of the blocks and sutures for understanding deep tectonic feature in this region. The geophysical survey region is located in about 97～98°E and 35～26°N, the profile with the length of 760km runs through Bayanhar, Qingtang and Gandise block in NS direction, 349 gravity and geomagnetic data were acquired simultaneously, and 31 MT sites are be placed along the profile with about 18km\|interval to detect electrical conductive feature.展开更多
The Qaidam Basin is a petroleum province in Northeastern Qinghai—Tibetan plateau, China. The Basin is bounded by the Aljin Mountains to the Northwest, the Qilian Mountains to the Northeast, the Qimantager Mountains t...The Qaidam Basin is a petroleum province in Northeastern Qinghai—Tibetan plateau, China. The Basin is bounded by the Aljin Mountains to the Northwest, the Qilian Mountains to the Northeast, the Qimantager Mountains to the Southeast and East Kunlun Mountains to the Southwest. The average elevation of the basin and these mountains are 2700m and 3000～ 5000 m respect to the sea level, respectively. The basin was developed on the pre\|Mesozoic basement. Thickness of Tertiary system is more than 10000m in the basin,but Quaternary is mainly in the eastern basin with thickness more than 3000m. The lithology in Mesozoic and Cenozoic of the basin are mainly sandstone, shale, calcic rocks and the interlayers of sandstone and shale.展开更多
The Cenozoic volcanic rocks in the Yumen and Hoh Xil area formed in the intracontinental orogenic belt, which primary magma originated from a particular enrichment upmantle and accreted crust\|mantle belt or directly ...The Cenozoic volcanic rocks in the Yumen and Hoh Xil area formed in the intracontinental orogenic belt, which primary magma originated from a particular enrichment upmantle and accreted crust\|mantle belt or directly originated from asthenosphere superface by partial melting of pyrolite.Through the deeply study of the Cenozoic volcanic rocks, the effective petrological constraints on the deep\|internal geology process can be obtained. And of course, it is the window for discussion the orogeny/uplift machinism of the Qinghai—Tibet plateau.1\ Brief regional geology\;The Yumen Cenozoic volcanic rock lithodistrict belongs to the north margin of Qinghai—Tibet plateau. This lithodistrict mainly consists of Hongliuxia and Hanxia volcanic rock bodies. The Hongliuxia Pleistocene epoch volcano neck is located to the northwest of Yumen City about 40km away, consisted of tephrite and trachybasalt. The boundary line between the volcano neck and the country rocks well defined and the contact plane is almost erect. The drag structure and wrinkle have been identified in the country rocks, which were due to the upthrusting of the magma. About 100 meters away to the south of the volcano neck, there is a basaltic flowage which covers on the Cretaceous—Tertiary shale and argillaceous sandstone.The Hanxia Cenozoic volcanic rock lithodistrict is located to the west of Yumen City about 15km away, which is a river valley extending into the north piedmont of Qilian Mountain. It dissected the Cretaceous—Tertiarystratigraphic sequence. The Cenozoic volcanic rock distributed in the Hanxia river valley is a lava flowage and NWW\|trending as a long lava dome.The Hoh Xil Cenozoic volcanic rock lithodistrict is located in the north part of Qinghai—Tibet plateau. The Cenozoic intensely intracontinental volcanism in this region had formed a number of lava sheets and subvolcanic rock bodies which were in different size and now present as lava platforms with about an elevation of 5000 meters. Affected by the preexisting NWW\|trending structure zones, there formed several NWW\|trending active\|volcano zones in the area during the Cenozoic era when the magma overflowed and/or intruded near to th e ground surface.展开更多
In this paper,218 long period Rayleigh wave records from 7 seismic station of CDSN are selected.We applied a partitioned waveform inversion to these data in order to construct a 3\|D model of shear velocity down to 40...In this paper,218 long period Rayleigh wave records from 7 seismic station of CDSN are selected.We applied a partitioned waveform inversion to these data in order to construct a 3\|D model of shear velocity down to 400km depth in the crust and upper mantle of Qinghai\|Tibet plateau and Its Adjacent Regions (22°～44°N,70°～110°E).The first step of the waveform inversion used involved the matching of the waveforms of fundamental and highermost Ravleigh waves with waveforms synthesized from stratified models;in the second stage,the 3\|D model was constructed by solve linear constrains equation. The major structural features inferred from the surface waveform inversions can be summarized as follows:(1) There is a great contrast between surface waveform through Qinghai—Thibet plateau and the others.Main frequency of the former is lower than the latter, which indicate the crust depth of Qinghai—Tibet plateau is deeper than the others. In addition,the amplitude of about 30s period and 50s period is lower than both sides,which implied these exist lower velocity layer at about 25km depth and about 50km depth in Qinghai—Tibet plateau Crust.The former is common,the latter was argued because resolution of most method can not prove it.展开更多
Eclogite was firstly discovered at the Da Qaidam region (Yang,et al., 1998), and then in the Xitieshan and Dulan regions in 1999, constituting an over 350km long high\|pressure metamorphic belt in the northeastern Qin...Eclogite was firstly discovered at the Da Qaidam region (Yang,et al., 1998), and then in the Xitieshan and Dulan regions in 1999, constituting an over 350km long high\|pressure metamorphic belt in the northeastern Qinghai—Tibet plateau. Eclogites occur as pods in the garnet\|muscovite gneiss of the Dakendaban Group (or called Shaliuhe Group in Dulan) of Upper Proterozoic age. In general, the pods of eclogite vary in size; most of them are less than 20m×10m, some large ones up to about 100m×50m. The eclogite\|hosted gneiss is pale\|gray in color, consisting mainly plagioclase and quartz, and minor muscovite (5%～10% in vol.) and garnet (1%～2%). Some of the country rocks of eclogite are mica\|quartz\|(feldspar) schist, quartzite, and ultramafic rocks, the latter also occur in blocks.Over 50 pods were found in a belt of 10km×3km in the Da Qaidam region (No.1 location). Only a few pods of eclogite were found in the Xitieshan region in 1999 field expedition (No.2 location). Eclogite in Dulan occurs in the Proterozoic strata of Shaliuhe Group (same as the Dakendaban Group but with a different name). The eclogites in the Dulan region (No.3 location) expose about 10km wide in SN and an unknown length in EW, and can be subdivided into two belts, the North Eclogite Belt of Dulan (NEBD) and the South Eclogite Belt of Dulan (SEBD).展开更多
The uplift of the QinghaiXizang(Tibet) Plateau happened indifferent crustal movements and different time from those of the collision of Asia continent with the allochthonous India crustobody, and the uplift occurred v...The uplift of the QinghaiXizang(Tibet) Plateau happened indifferent crustal movements and different time from those of the collision of Asia continent with the allochthonous India crustobody, and the uplift occurred very long after the finish of the collision. According to its temporal evolution, the uplift happened in another active stage of the mantle creep flow after the active stage resulting in the collision and the interruption of the 140Ma′s quiet stage. On the basis of the dynamic analysis, the uplift resulted from the multiple compressing stresses in the reactivation stage after weakening of the colliding stress and the following compressing stress, and after the interruption of the stable stage dominating the vertical movements and represented by formation of the universal QinghaiXizang(Tibet) ancient platform. It was the production of another stress field existing in another crustobody evolution stage and growth age. In the light of the nature of the orogeny, the uplift was caused by the intracontinental Diwa (geodepression)type orogeny after converging connection of the Central Asia Crustobody and the India crustbody which immediately became a part of the Asia continent, and hence after the substitution for the colliding stress and the following compressing stress by the platformtype crustal movements.展开更多
The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies,...The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies, such as layered intrusions (V\|Ti\|Fe formation), small\|sized mafic\|ultramafic bodies (stocks) and large\|scale basalt (Emeishan Basalt) are constituted of a complete melanocratic rock system.Most of Cu\|Ni\|PGE sulfide deposits are related to small\|sized ultramafic rock bodies. It is a perfect possibility for them to be an affinity of basic eruptive lava and for the neck facies. But in ① Panzhihua\|Center Yunnan Province, the Gaojiacun, also Jinbaoshan, as large stratiform basic\|ultrabasic complex used to be thought that is older one intruded to basement rocks in Precambrian. However, new evidences suggest it is similar with the small\|sized ultramafic rock bodies containing Cu\|Ni\|PGE, and also the both are affinity of the Emeishan Basalt; ② Miyi district, Cu\|Pt mineralization was discovered in the Xinjie bedded basic complex, and in where ophitic olivine\|pyroxenite\|peridotite facies are exactly Pt\|bearing layers; ③ Longzhoushan district, we have recently researched basic\|ultrabasic clusters which intruded into fracture zones, and Cu\|Ni\|Pt, Pd mineralization developed at the salbands.Generally, the basalt is poor in PGE and rich in Cu. It is suggested as the result of PGE dispersion\|concentration processing in the melanocratic rock system when rifting happened.展开更多
The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are region...The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are regionally unconformable between each adjacent two of the Middle-Late Triassic fine grained clastic,the Jurassic coal-containing clastic,the Cretaceous-Paleogene variegated coarse clastic。展开更多
It is one of hot issues in Tibetan research that is to study the mode,process and kinetics of the crustal shortening during Mesozoic-Cenozoic.In this paper, on the basis of systematic collection,analysis and research ...It is one of hot issues in Tibetan research that is to study the mode,process and kinetics of the crustal shortening during Mesozoic-Cenozoic.In this paper, on the basis of systematic collection,analysis and research of the existing data and results from Himalayas,Lhasa and Qiangtang terranes,we conducted the balanced cross-section study.In the north Qiangtang,the line-balanced cross-section展开更多
GPS observations of CMONOC and other network reveal that, relative to Dingxin fiducial station in Alashan block, the crustal movements of north eastern Qinghai Tibet plateau and its adjacent regions have the following...GPS observations of CMONOC and other network reveal that, relative to Dingxin fiducial station in Alashan block, the crustal movements of north eastern Qinghai Tibet plateau and its adjacent regions have the following characteristics:(i)The western part of Qilian block is shortening and moving mainly northeastward, the 8 mm/a motion of southern margin of Qaidam basin is almost completely absorbed by compressed subsidence of Qaidam basin and uplift of Qilian mountain; (ii) Eastern part of Qilian block manifests itself mainly as block like rotation or extrusion along Haiyuan left lateral fault,with an angular velocity of 0.135 /Ma; (iii) Due to the clockwise rotation of the eastern Qilian sub block in the NW Liupanshan range, Ordos block shows a slight anticlockwise rotation; (iv) Haiyuan left lateral fault and northern edge thrust fault of Qilian mountain jointly constitute the major northeastern boundary of Qinghai Tibet plateau judging from the present day crustal movement.展开更多
Aimed at the characteristics of permafrost temperature influencing the safety of Qinghai-Tibet Railway and its on-line testing system, comparing the achievement of permafrost study nationwide with those worldwide, an ...Aimed at the characteristics of permafrost temperature influencing the safety of Qinghai-Tibet Railway and its on-line testing system, comparing the achievement of permafrost study nationwide with those worldwide, an automatic testing system of permafrost temperature, containing a master computer and some slave computers, was designed. By choosing high-precise thermistors as temperature sensor, designing and positioning the depth and interval of testing sections, testing, keeping and sending permafrost temperature data at time over slave computers, and receiving, processing and analyzing the data of collecting permafrost temperature over master computer, the change of the permafrost temperature can be described and analyzed, which can provide information for permafrost railway engineering design. Moreover, by taking permafrost temperature testing in a certain section of Qinghai-Tibet Railway as an instance, the collected data of permafrost temperature were analyzed, and the effect of permafrost behavior was depicted under the railway, as well as, a BP model was set up to predict the permafrost characteristics. This testing system will provide information timely about the change of the permafrost to support the safety operation in Qinghai-Tibet Railway.展开更多
文摘The Qinghai—Tibet plateau and its surrounding areas including Indian subcontinent, Xinjiang, Mongolia, is a largest lithosphere convergence place in the world, which characterized by continent\|continent collision with a thick crust and lithosphere. The high resolution seismic surface wave tomographic inversion has been conducted for studying the 3D velocity structure of crust and upper mantle in those areas. The seismic surface waveform data are from the archives of the CDSN, GSN and GEOSCOPE. About 2400 long period surface waveform recordings are available for both dispersion and waveform tomographic inversion. The block inversion by grid 1°×1°in Qinghai—Tibet plateau and 2°×2°in the surrounding areas were adapted. The resulting maps show the high resolution 3D shear wave velocity variation from earth’s surface to 400km depth.
文摘Located in the northern margin of the Qinghai—Tibet Plateau, the Longshoushan Mt. is a small block between Qinghai—Tibet Landmass and Alashan Landmass.Traditional tectonic viewpoint does not consider that the Longshoushan Mt. is a single tectonic block. It is quite evident that there is only a hazy idea about the Longshoushan block. Though there is a very complex tectonic region between Qinghai—Tibet Landmass and Alashan Landmass, the Longshoushan block in the region shows unique tectonic landforms, deep structures and uplift mechanisms. Researching into the relationship between the Longshoushan block and the Qinghai—Tibet and Alashan Landmasses will contribute to the realization of boundary and orogenic belt on the northern margin of the Qinghai—Tibet block. It is a very important scientific subject.The Longshoushan Mt., longer than 150km in NWW direction and wider than 10km, is located on the northern side of Hexi corridor(100 5°～102 5°E,38 5°～39 3°N). It extends from the northwest of Zhangye to Hexibu, and from the south of Chaoshui basin to the north of Minle basin. From west to east, there are the highest peak, Dongdashan Mt.(3616m), the second peak, Dufengding(2937m) and Qianshan peak(2827m), height of the mountains is getting lower and lower, mean height above sea level is over 2000m, and relative height difference is about 1000m. The Longshoushan Mt. provides a natural defence for stopping the southward migration of sandstorm in the Hexi corridor, and forms a topographic step zone from the Alashan Plateau to the Qinghai—Tibet Plateau. In the Longshoushan area, developed landforms, such as planation surface, table\|land, terrace land, are general characters of all geomorphic units. It is shown that the Longshoushan Mt. is a intermittently uplifted block. An astonishingly similar of geometric patterns of Taohualashan Mt. and Hongshihu basin is very interesting natural landscape in the area. It is suggested that Taohualashan Mt. broke away from Hongshihu Basin in secular tectonic movement. The viewpoint is supported by major formation, lithofacies, limitation and style of active faulting. The Longshoushan block consists of two major active fault zones (the northern Longshoushan fault zone and the southern Longshoushan fault zone), the active Pingshanhu—Hongshihu fault basin belt and Taohualashan—Xieposhan tectonic uplift belt. In addition, there are the NNW\|trending West Polamading fault, NWW\|trending Maohudong fault trough, NNE\|trending Daxiahe rift valley and others on the block. the activity and formation style of these structures indicate that the block is acted not only by compressive stress, but also by tensile stress. The northern Longshoushan and southern Longshoushan fault zones are closely related to formation and evolution of the Longshoushan block, the two zones are active fault zones since late Pleistocene and boundary fault zones of the block. The genesis and activity style of the Pingshanhu\|Hongshihu basin are similar to the continental rift, which may be due to the mantle uplift.
文摘Finite strain patterns of rocks The structural styles and crustal shortening in the northern margin of Qinghai—Tibet plateau are examined by systematic finite strain measurements. The finite strain patterns in this area are of following characteristics:① The orientation of & principal axes of strain ellipsoid varies regularly in regard to different tectonic locations. In fact, most of the measured X axes are parallel to the regional structure lines, striking east\|west or approximately east\|west with some X axes trending northeast\|southwest. The measured Z\|axes are approximately at right angle to the regional structure lines, trending north\|northeast or north\|northwest.② The Flinn parameter k is higher in the northern and southern margins of the basin than that in the basin center, indicating that the margins of basin experienced extensional strain and the middle of basin undergo strain.③ Rocks of different age possess different strain state and show k value of 1～2 for Tertiary rocks, 3～4 for Jurassic—Cretaceous rocks. The k value of the basement rocks is the highest of all.
文摘Recently, this study group established “the map of MOHO\|surface bathymetric line in Chinese and Near Region" on the basis of latest survey and study of the crustal depth, the preliminary result shows that the regular meridional and latitudinal upwarping and downwarping structural pattern of MOHO\|surface bathymetric line among Eurasian plate and Pacific plate and the Indian plate alternately appears, and which is accreted and coupled with basin ridge structure that exist shallow crustal base, continental crust and oceanic crust and others regular upwarping and downwarping net structure system that possessing different block characters and different scales exist together. Among different structure systems, it occurs that ramp downwarping impetus transform structure belts whose trends is characteristic. Nowadays upwarping and downwarping net structure system is basically modeled in Himalayan orogeny period. It is showed that the Earth revolution way has been changed in this period, which leaded to a new Earth dynamics cycle.The pattern of upwarping and downwarping structure among different structure systems or different structure blocks , and the characters of different trends and different scale transform structure belts, reflects the structure movement way and their conversion law, and reveals the Earth centralized dynamics mechanics that is produced by the revolutionary effect under the environments of aster system. This can be clearly reflected by the change of impetus way between Qinghai—Tibet highland structure system and near structure system.
文摘The Northeastern margin of Qinghai—Tibet plateau,here refers to the region bounded by Western Qinling fault zone and Longshoushan—Liupanshan tectonic zone, where obliquely compression deformation occurred with the NE\|trending maximum principle axis of stress, with Ordos Massif to the east, Alaxa Block to the north, and Qinghai—Tibet plateau to the southwest. The main structure in this region is Haiyuan—Gulang transpression zone. It consists of a series of active faults: the Haiyuan fault zone, the Tianjingshan fault zone, the Yantongshan fault zone and the Niushoushan—Luoshan fault zone.
文摘Based on the studies of geology and geochemistry, A’nymaque—Mianlue limited oceanic basin is comparable to the Paleo\|Tethys on time, sedimentary, biocoenosis, and the type of ophiolite (Coleman, 1984; Deng, 1984; Xu, 1996;Chenliang, 1999). The A’nyemaqen—Mianlue oceanic basin was one of a northeast branches of Paleo\|Tethys (Zhang Guowei, 1995; 1996) .Our researches on deformations reveal that tectonic styles of the Southwest Qinling orogenic belt is obviously influenced by the dynamics of Qinghai—Tibet plateau.Structural deformation analysis suggested that the southwest part of Qinling have undergone 3 major deformation stages in Mesozoic and Cenozoic. Firstly, rock folding at deep\|middle tectonic level and progressively thrusting shearing characterized the deformation of collision. The thrust tectonics are south\|directed, such as A’nymaque, Wenxian—Kangxian and Mianlue thrusting systems, and the deformations took place in T\-2—T\-3. Secondly, the middle\|tectonic level thrusting and sinistral strike\|slip formed at early intracontinental period (J—K), the thrust tectonics was south\|directed and the regional penetrative left\|lateral slips were NW or NWW. Finally, the east\|west extensional deformations which occurred in late Mesozoic and Cenozoic, a series of north\|south directing basins came into being in this stage, Huixian—Chengxian basin and Lixian basin for example, which overlapped the former deformation styles.
文摘The uplift history has been becoming the key for the geological science of Qinghai—Tibet plateau. The scholars abroad have reconstructed uplift history of the plateau by studying geological process of the inner globe, they considered that the altitude of the plateau got up to the maximum at 14Ma (M.Coleman et al, 1995; S.Turner et al, 1993)or the plateau got to the present elevation at about 8Ma (T.M.Harrison,1992). The Chinese geologists make use of substitutes of outer environmental elements to deduce that the uplift of Qinghai—Tibet plateau began from 3 4Ma(Li Jijun,1995). It is obvious that there are the different views and controversies about the plateau uplift history.
文摘The scientific research on Qinghai—Tibet Plateau has already been the hot and key point on the plateau evolvement, the earth ecological variety, as well as the society harmonious development. The research on Qinghai—Tibet Plateau has the following characteristics:(1) 4\|dimension of time and space: with a vast territory and very deep depth, as well as the big time span.(2) Wide fields and across subjects: including geology, environment, ecology, climate, land, agriculture, forestry, animal husbandry, etc.(3) Theory and practice with profound and lasting influence: the research results can be great function for the direction in understanding the world, ecological environment and the human living conditions.The current issues of the research on Qinghai—Tibet Plateau are as follows:(1) Thousands of papers concerned about Qinghai—Tibet Plateau are lack of quantification data, and the research results are not displayed vividly.(2) The study scopes are more in the portion and less in the whole.(3) There are not enough work of combination of depth study with surface study, the representation in 3\|D is limited.(4) The study of time variation is not enough and there is poor way to show the time series results.(5) There are not enough work in the different specialties intercross, as well as the synthesis study of interdisciplinary subjects and cross subjects.
文摘The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basin above 2300m ASL.The basin has deposited different kinds of sediments with 1600m in depth. The early Tertiary strata were first named as Lijiang formation in 1961, and later named as Hongyanzi formation. The later Tertiary strata, the lignite\|bearing strata, were once named as Xigeda formation. Li Yougheng(1978) found some mammal fossils in the strata, so they named it Yanyuan formation. The Hongyanzi Formation which thickness is 1022m can be divided into five members according to the lithologic characters. The first one is mainly made of purplish\|red coarse conglomerates. The composition of gravel mainly consists of limestone and purplish\|red sandstone and marl. The second one consists of sandstone interbedded with conglomerate. The member has three cyclic sequences from conglomerate to sandstone. The composition of gravel of this member is mainly limestone. From bottom to top the degree of sorting and roundness tends to be well. In sandstones or sand lenticules the oblique bedding and trough cross\|bedding can be seen. The third one is the member of sandstone and mudstone. The sandstone is light purple while the mudstone is purplish red. Ripple marks can be seen in the sandstone. The forth one consists of conglomerate interbedded with mudstone, The conglomerate and the sandstone assume three cyclic sequences. The composition of the gravel is chiefly limestone. The fifth one is a member of light purple massive conglomerate. The composition of the gravel is limestone. The imbricate structure can be seen in the conglomerate. The strata belong to later Eocene epoch in accordance with the fossils of mammals, plants and ostracoda in it.
文摘A geophysical survey including Magnetotelluric sounding(MT), gravity and geomagnetism was carried out in eastern region of Qinghai—Tibet plateau in 1998. It is to be known from tectonic map that study area was divided into four blocks by three large sutures, but we have very little information on deep\|seated structure which have close relationship with evolution of Tibet plateau, our purpose is to find some deep crustal structure evidences of the blocks and sutures for understanding deep tectonic feature in this region. The geophysical survey region is located in about 97～98°E and 35～26°N, the profile with the length of 760km runs through Bayanhar, Qingtang and Gandise block in NS direction, 349 gravity and geomagnetic data were acquired simultaneously, and 31 MT sites are be placed along the profile with about 18km\|interval to detect electrical conductive feature.
文摘The Qaidam Basin is a petroleum province in Northeastern Qinghai—Tibetan plateau, China. The Basin is bounded by the Aljin Mountains to the Northwest, the Qilian Mountains to the Northeast, the Qimantager Mountains to the Southeast and East Kunlun Mountains to the Southwest. The average elevation of the basin and these mountains are 2700m and 3000～ 5000 m respect to the sea level, respectively. The basin was developed on the pre\|Mesozoic basement. Thickness of Tertiary system is more than 10000m in the basin,but Quaternary is mainly in the eastern basin with thickness more than 3000m. The lithology in Mesozoic and Cenozoic of the basin are mainly sandstone, shale, calcic rocks and the interlayers of sandstone and shale.
文摘The Cenozoic volcanic rocks in the Yumen and Hoh Xil area formed in the intracontinental orogenic belt, which primary magma originated from a particular enrichment upmantle and accreted crust\|mantle belt or directly originated from asthenosphere superface by partial melting of pyrolite.Through the deeply study of the Cenozoic volcanic rocks, the effective petrological constraints on the deep\|internal geology process can be obtained. And of course, it is the window for discussion the orogeny/uplift machinism of the Qinghai—Tibet plateau.1\ Brief regional geology\;The Yumen Cenozoic volcanic rock lithodistrict belongs to the north margin of Qinghai—Tibet plateau. This lithodistrict mainly consists of Hongliuxia and Hanxia volcanic rock bodies. The Hongliuxia Pleistocene epoch volcano neck is located to the northwest of Yumen City about 40km away, consisted of tephrite and trachybasalt. The boundary line between the volcano neck and the country rocks well defined and the contact plane is almost erect. The drag structure and wrinkle have been identified in the country rocks, which were due to the upthrusting of the magma. About 100 meters away to the south of the volcano neck, there is a basaltic flowage which covers on the Cretaceous—Tertiary shale and argillaceous sandstone.The Hanxia Cenozoic volcanic rock lithodistrict is located to the west of Yumen City about 15km away, which is a river valley extending into the north piedmont of Qilian Mountain. It dissected the Cretaceous—Tertiarystratigraphic sequence. The Cenozoic volcanic rock distributed in the Hanxia river valley is a lava flowage and NWW\|trending as a long lava dome.The Hoh Xil Cenozoic volcanic rock lithodistrict is located in the north part of Qinghai—Tibet plateau. The Cenozoic intensely intracontinental volcanism in this region had formed a number of lava sheets and subvolcanic rock bodies which were in different size and now present as lava platforms with about an elevation of 5000 meters. Affected by the preexisting NWW\|trending structure zones, there formed several NWW\|trending active\|volcano zones in the area during the Cenozoic era when the magma overflowed and/or intruded near to th e ground surface.
文摘In this paper,218 long period Rayleigh wave records from 7 seismic station of CDSN are selected.We applied a partitioned waveform inversion to these data in order to construct a 3\|D model of shear velocity down to 400km depth in the crust and upper mantle of Qinghai\|Tibet plateau and Its Adjacent Regions (22°～44°N,70°～110°E).The first step of the waveform inversion used involved the matching of the waveforms of fundamental and highermost Ravleigh waves with waveforms synthesized from stratified models;in the second stage,the 3\|D model was constructed by solve linear constrains equation. The major structural features inferred from the surface waveform inversions can be summarized as follows:(1) There is a great contrast between surface waveform through Qinghai—Thibet plateau and the others.Main frequency of the former is lower than the latter, which indicate the crust depth of Qinghai—Tibet plateau is deeper than the others. In addition,the amplitude of about 30s period and 50s period is lower than both sides,which implied these exist lower velocity layer at about 25km depth and about 50km depth in Qinghai—Tibet plateau Crust.The former is common,the latter was argued because resolution of most method can not prove it.
文摘Eclogite was firstly discovered at the Da Qaidam region (Yang,et al., 1998), and then in the Xitieshan and Dulan regions in 1999, constituting an over 350km long high\|pressure metamorphic belt in the northeastern Qinghai—Tibet plateau. Eclogites occur as pods in the garnet\|muscovite gneiss of the Dakendaban Group (or called Shaliuhe Group in Dulan) of Upper Proterozoic age. In general, the pods of eclogite vary in size; most of them are less than 20m×10m, some large ones up to about 100m×50m. The eclogite\|hosted gneiss is pale\|gray in color, consisting mainly plagioclase and quartz, and minor muscovite (5%～10% in vol.) and garnet (1%～2%). Some of the country rocks of eclogite are mica\|quartz\|(feldspar) schist, quartzite, and ultramafic rocks, the latter also occur in blocks.Over 50 pods were found in a belt of 10km×3km in the Da Qaidam region (No.1 location). Only a few pods of eclogite were found in the Xitieshan region in 1999 field expedition (No.2 location). Eclogite in Dulan occurs in the Proterozoic strata of Shaliuhe Group (same as the Dakendaban Group but with a different name). The eclogites in the Dulan region (No.3 location) expose about 10km wide in SN and an unknown length in EW, and can be subdivided into two belts, the North Eclogite Belt of Dulan (NEBD) and the South Eclogite Belt of Dulan (SEBD).
文摘The uplift of the QinghaiXizang(Tibet) Plateau happened indifferent crustal movements and different time from those of the collision of Asia continent with the allochthonous India crustobody, and the uplift occurred very long after the finish of the collision. According to its temporal evolution, the uplift happened in another active stage of the mantle creep flow after the active stage resulting in the collision and the interruption of the 140Ma′s quiet stage. On the basis of the dynamic analysis, the uplift resulted from the multiple compressing stresses in the reactivation stage after weakening of the colliding stress and the following compressing stress, and after the interruption of the stable stage dominating the vertical movements and represented by formation of the universal QinghaiXizang(Tibet) ancient platform. It was the production of another stress field existing in another crustobody evolution stage and growth age. In the light of the nature of the orogeny, the uplift was caused by the intracontinental Diwa (geodepression)type orogeny after converging connection of the Central Asia Crustobody and the India crustbody which immediately became a part of the Asia continent, and hence after the substitution for the colliding stress and the following compressing stress by the platformtype crustal movements.
文摘The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies, such as layered intrusions (V\|Ti\|Fe formation), small\|sized mafic\|ultramafic bodies (stocks) and large\|scale basalt (Emeishan Basalt) are constituted of a complete melanocratic rock system.Most of Cu\|Ni\|PGE sulfide deposits are related to small\|sized ultramafic rock bodies. It is a perfect possibility for them to be an affinity of basic eruptive lava and for the neck facies. But in ① Panzhihua\|Center Yunnan Province, the Gaojiacun, also Jinbaoshan, as large stratiform basic\|ultrabasic complex used to be thought that is older one intruded to basement rocks in Precambrian. However, new evidences suggest it is similar with the small\|sized ultramafic rock bodies containing Cu\|Ni\|PGE, and also the both are affinity of the Emeishan Basalt; ② Miyi district, Cu\|Pt mineralization was discovered in the Xinjie bedded basic complex, and in where ophitic olivine\|pyroxenite\|peridotite facies are exactly Pt\|bearing layers; ③ Longzhoushan district, we have recently researched basic\|ultrabasic clusters which intruded into fracture zones, and Cu\|Ni\|Pt, Pd mineralization developed at the salbands.Generally, the basalt is poor in PGE and rich in Cu. It is suggested as the result of PGE dispersion\|concentration processing in the melanocratic rock system when rifting happened.
文摘The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are regionally unconformable between each adjacent two of the Middle-Late Triassic fine grained clastic,the Jurassic coal-containing clastic,the Cretaceous-Paleogene variegated coarse clastic。
文摘It is one of hot issues in Tibetan research that is to study the mode,process and kinetics of the crustal shortening during Mesozoic-Cenozoic.In this paper, on the basis of systematic collection,analysis and research of the existing data and results from Himalayas,Lhasa and Qiangtang terranes,we conducted the balanced cross-section study.In the north Qiangtang,the line-balanced cross-section
文摘GPS observations of CMONOC and other network reveal that, relative to Dingxin fiducial station in Alashan block, the crustal movements of north eastern Qinghai Tibet plateau and its adjacent regions have the following characteristics:(i)The western part of Qilian block is shortening and moving mainly northeastward, the 8 mm/a motion of southern margin of Qaidam basin is almost completely absorbed by compressed subsidence of Qaidam basin and uplift of Qilian mountain; (ii) Eastern part of Qilian block manifests itself mainly as block like rotation or extrusion along Haiyuan left lateral fault,with an angular velocity of 0.135 /Ma; (iii) Due to the clockwise rotation of the eastern Qilian sub block in the NW Liupanshan range, Ordos block shows a slight anticlockwise rotation; (iv) Haiyuan left lateral fault and northern edge thrust fault of Qilian mountain jointly constitute the major northeastern boundary of Qinghai Tibet plateau judging from the present day crustal movement.
基金Project(2007XM036) supported by the Science and Technology of Beijing Jiaotong University, China
文摘Aimed at the characteristics of permafrost temperature influencing the safety of Qinghai-Tibet Railway and its on-line testing system, comparing the achievement of permafrost study nationwide with those worldwide, an automatic testing system of permafrost temperature, containing a master computer and some slave computers, was designed. By choosing high-precise thermistors as temperature sensor, designing and positioning the depth and interval of testing sections, testing, keeping and sending permafrost temperature data at time over slave computers, and receiving, processing and analyzing the data of collecting permafrost temperature over master computer, the change of the permafrost temperature can be described and analyzed, which can provide information for permafrost railway engineering design. Moreover, by taking permafrost temperature testing in a certain section of Qinghai-Tibet Railway as an instance, the collected data of permafrost temperature were analyzed, and the effect of permafrost behavior was depicted under the railway, as well as, a BP model was set up to predict the permafrost characteristics. This testing system will provide information timely about the change of the permafrost to support the safety operation in Qinghai-Tibet Railway.
