The India plates continuous motion to the north, the convective removal to the thickening lithosphere caused by small-scale mantle convection and the effect of denudation on the uplifted plateau are regarded as main d...The India plates continuous motion to the north, the convective removal to the thickening lithosphere caused by small-scale mantle convection and the effect of denudation on the uplifted plateau are regarded as main driving forces that make the patterns of stress field of East Asia continent at present time. The method of numerical simulation is used to study the deformation and the stress field of East Asia continent under different boundary conditions, different denudation coefficients and different rock mechanics parameters within a trapezoid geological frame. Comparing with the results obtained by modern space geodetic technique (such as GPS) the results derived from seismological data show that the predicted data by our model can fit them very well. The degree of the fitness in the west is better than that in the east. These results imply that the main driving force of the deformation and the stress patterns of the west part of East Asia continent may come from the collision and compression between the India and the Eurasia plates. The interaction to the Pacific and the Philippines plates in the east part need to be considered. It also shows that the convective removal to the thickening lithosphere caused by small-scale mantle convection and the effect of denudation cannot be negligible in the evolution of the stress patterns.展开更多
From an angle of integrative analysis on historical-dynamic geotectonics, the formation mechanism of the Eastern Asia continental-margin and historical background of the evolution-movement of the crustobody are discus...From an angle of integrative analysis on historical-dynamic geotectonics, the formation mechanism of the Eastern Asia continental-margin and historical background of the evolution-movement of the crustobody are discussed. The pull-breaking-extending and thinning of the continental margin crustobody in the region result in the formation of the continental-margin extensional belt.Finally, the theoretical and practical significance of the study is pointed out.展开更多
Placing precise constraints on the timing of the India-Asia continental collision is essential to understand the successive geological and geomorphological evolution of the orogenic belt as well as the uplift mechanis...Placing precise constraints on the timing of the India-Asia continental collision is essential to understand the successive geological and geomorphological evolution of the orogenic belt as well as the uplift mechanism of the Tibetan Plateau and their effects on climate,environment and life.Based on the extensive study of the sedimentary record on both sides of the Yarlung-Zangbo suture zone in Tibet,we review here the present state of knowledge on the timing of collision onset,discuss its possible diachroneity along strike,and reconstruct the early structural and topographic evolution of the Himalayan collided range.We define continent-continent collision as the moment when the oceanic crust is completely consumed at one point where the two continental margins come into contact.We use two methods to constrain the timing of collision onset:(1) dating the provenance change from Indian to Asian recorded by deep-water turbidites near the suture zone,and(2) dating the age of unconformities on both sides of the suture zone.The first method allowed us to constrain precisely collision onset as middle Palaeocene(59±l Ma).Marine sedimentation persisted in the collisional zone for another 20-25 Ma locally in southern Tibet,and molassic-type deposition in the Indian foreland basin did not begin until another 10-15 Ma later.Available sedimentary evidence failed to firmly document any significant diachroneity of collision onset from the central Himalaya to the western Himalaya and Pakistan so far.Based on the Cenozoic stratigraphic record of the Tibetan Himalaya,four distinct stages can be identified in the early evolution of the Himalayan orogen:(1) middle Palaeocene-early Eocene earliest Eohimalayan stage(from 59 to 52 Ma):collision onset and filling of the deep-water trough along the suture zone while carbonate platform sedimentation persisted on the inner Indian margin;(2) early-middle Eocene early Eohimalayan stage(from 52 to 41 or 35 Ma):filling of intervening seaways and cessation of marine sedimentation;(3) late Eocene-Oligocene late Eohimalayan stage(from 41 to 25 Ma):huge gap in the sedimentary record both in the collision zone and in the Indian foreland;and(4) late Oligocene-early Miocene early Neohimalayan stage(from 26 to 17 Ma):rapid Himalayan growth and onset of molasse-type sedimentation in the Indian foreland basin.展开更多
This is a review of the formation and tectonic evolution of the continental Asia in Phanerozoic.The continental Asia has formed on the bases of some pre-Cambrian cratons,such as the Siberia,India,Arabia,North China,Ta...This is a review of the formation and tectonic evolution of the continental Asia in Phanerozoic.The continental Asia has formed on the bases of some pre-Cambrian cratons,such as the Siberia,India,Arabia,North China,Tarim,South China,and Indochina,through multi-stage plate convergence and collisional collages in Phanerozoic.The north-central Asia had experienced the expansion and subduction of the Paleo-Asian Ocean(PAO)in the early Paleozoic and the closure of the PAO in the late Paleozoic and early Mesozoic,forming the PAO regime and Central Asian orogenic belt(CAOB).In the core of the CAOB,the Mongol-Okhotsk Ocean(MOO)opened with limited expansion in the Early Permian and finally closed in the Late Jurassic–Early Cretaceous.The south-central Asia had experienced mainly multi-stage oceanic opening,subduction and collision evolution in the Tethys Ocean,forming the Tethys regime and Himalaya-Tibetan orogenic belt.In eastern Asia,the plate subduction and continental margin orogeny on western margin of the Pacific Ocean,forms the West Pacific regime and West Pacific orogenic belt.The PAO,Tethys,and West Pacific regimes,together with Precambrian cratons among or surrounding them,made up the major tectonic and dynamic systems of the continental Asia in Phanerozoic.Major tectonic events,such as the Early Paleozoic Qilian,Uralian,and Dunhuang orogeneses,the late Paleozoic East Junggar,Tianshan and West Junggar orogeneses,the Middle to Late Permian Ailaoshan orogeny and NorthSouth Lhasa collision,the early Mesozoic Indochina-South China and North-South China collisions,the late Mesozoic Mongolia-Okhotsk orogeny,Lhasa-Qiangtang collision,and intra-continental Yanshanian orogeny,and the Cenozoic IndoAsian,Arab-Asian,and West Pacific margin collisions,constrained the formation and evolution of the continental Asia.The complex dynamic systems have left large number of deformation features,such as large-scale strike-slip faults,thrustfold systems and extensional detachments on the continental Asia.Based on past tectonics,a future supercontinent,the Ameurasia,is prospected for the development of the Asia in ca.250 Myr.展开更多
The primary goal of the demonstration project endorsed by the Scientific and Technical Committee for IDNDR in 1992 is to ensure that national agencies are able to assess seismic hazard in a regionally coordinated fash...The primary goal of the demonstration project endorsed by the Scientific and Technical Committee for IDNDR in 1992 is to ensure that national agencies are able to assess seismic hazard in a regionally coordinated fashion by using advanced methods.China,as a Regional Center of Central Southern Asia,has contacted with countries of the region to realistically practice seismic hazard assessments of Continental Asia.A test area located in the collision boundary between the Indian and Eurasian plates was chosen to examine the seismic hazard assessment approach in the regional coordinates.The seismotectonics and three versions of seismic sources of the test area are described in this paper and under the Global Seismic Hazard Assessment Program(GSHAP),guidelines an earthquake catalogue of the test area was assembled.Because of the incompleteness of earthquake data in different countries,we adopt different time windows for different magnitude intervals in order to obtain the seismicity parameters of sources.By展开更多
Different attempts have been done to deduce the shortening of the Himalayan belt during the India\|Asia convergence. Dewey et al. (1989) and Le Pichon et al.(1992) calculated an India\|Asia shortening of 2300～2150km ...Different attempts have been done to deduce the shortening of the Himalayan belt during the India\|Asia convergence. Dewey et al. (1989) and Le Pichon et al.(1992) calculated an India\|Asia shortening of 2300～2150km and 2800～3000km in the western and eastern syntaxes, respectively, since the late 45Ma. According to seafloor\|spreading reconstruction, a total shortening of 3000～500km was estimated after the initial contact of the two plates at 55～50Ma (Molnar and Tapponier, 1975 ; Molnar et al., 1988 ; Replumaz, 1999). Since 40Ma, the part of shortening only accommodated by the Himalayan belt was estimated around 470km in the western part (Coward and Butler, 1985) and 550 to 630km to the east (Ratsbacher et al., 1994 ; Replumaz, 1999). In contrast, global plate reconstructions suggest that the shortening in the Himalaya is of about 1250～250km (Achache et al., 1984 ; Powell et al., 1988 ; Dewey et al.,1989 ; Klootwijk et al., 1992 ; Matte et al., 1997). This discrepancy between the amount of shortening estimated by balancing the Himalayan belt and by plate reconstruction favour the existence of a greater India buried up to 1000km north of the present\|day Indus suture zone and subducted before Middle Eocene time (Klootwijk et al., 1979 ; Patriat and Achache, 1984).展开更多
基金The Development Program on National Key Basic Researches under the Project Mechanism and Prediction of Continental Strong Earthquakes (G19980407).
文摘The India plates continuous motion to the north, the convective removal to the thickening lithosphere caused by small-scale mantle convection and the effect of denudation on the uplifted plateau are regarded as main driving forces that make the patterns of stress field of East Asia continent at present time. The method of numerical simulation is used to study the deformation and the stress field of East Asia continent under different boundary conditions, different denudation coefficients and different rock mechanics parameters within a trapezoid geological frame. Comparing with the results obtained by modern space geodetic technique (such as GPS) the results derived from seismological data show that the predicted data by our model can fit them very well. The degree of the fitness in the west is better than that in the east. These results imply that the main driving force of the deformation and the stress patterns of the west part of East Asia continent may come from the collision and compression between the India and the Eurasia plates. The interaction to the Pacific and the Philippines plates in the east part need to be considered. It also shows that the convective removal to the thickening lithosphere caused by small-scale mantle convection and the effect of denudation cannot be negligible in the evolution of the stress patterns.
文摘From an angle of integrative analysis on historical-dynamic geotectonics, the formation mechanism of the Eastern Asia continental-margin and historical background of the evolution-movement of the crustobody are discussed. The pull-breaking-extending and thinning of the continental margin crustobody in the region result in the formation of the continental-margin extensional belt.Finally, the theoretical and practical significance of the study is pointed out.
基金supported by the National Natural Science Foundation of China(Grant No.41525007)the Stratigraphic Pilot Science and Technology Projects of the Chinese Academy of Sciences(Class B)(Grant No.XDB03010400)
文摘Placing precise constraints on the timing of the India-Asia continental collision is essential to understand the successive geological and geomorphological evolution of the orogenic belt as well as the uplift mechanism of the Tibetan Plateau and their effects on climate,environment and life.Based on the extensive study of the sedimentary record on both sides of the Yarlung-Zangbo suture zone in Tibet,we review here the present state of knowledge on the timing of collision onset,discuss its possible diachroneity along strike,and reconstruct the early structural and topographic evolution of the Himalayan collided range.We define continent-continent collision as the moment when the oceanic crust is completely consumed at one point where the two continental margins come into contact.We use two methods to constrain the timing of collision onset:(1) dating the provenance change from Indian to Asian recorded by deep-water turbidites near the suture zone,and(2) dating the age of unconformities on both sides of the suture zone.The first method allowed us to constrain precisely collision onset as middle Palaeocene(59±l Ma).Marine sedimentation persisted in the collisional zone for another 20-25 Ma locally in southern Tibet,and molassic-type deposition in the Indian foreland basin did not begin until another 10-15 Ma later.Available sedimentary evidence failed to firmly document any significant diachroneity of collision onset from the central Himalaya to the western Himalaya and Pakistan so far.Based on the Cenozoic stratigraphic record of the Tibetan Himalaya,four distinct stages can be identified in the early evolution of the Himalayan orogen:(1) middle Palaeocene-early Eocene earliest Eohimalayan stage(from 59 to 52 Ma):collision onset and filling of the deep-water trough along the suture zone while carbonate platform sedimentation persisted on the inner Indian margin;(2) early-middle Eocene early Eohimalayan stage(from 52 to 41 or 35 Ma):filling of intervening seaways and cessation of marine sedimentation;(3) late Eocene-Oligocene late Eohimalayan stage(from 41 to 25 Ma):huge gap in the sedimentary record both in the collision zone and in the Indian foreland;and(4) late Oligocene-early Miocene early Neohimalayan stage(from 26 to 17 Ma):rapid Himalayan growth and onset of molasse-type sedimentation in the Indian foreland basin.
基金supported by the National Key Research and Development Program of China(the DREAM—Deep Resource Exploration and Advanced MiningGrant No.2018YFC0603701)the China Geological Survey(Grant nos.DD20160083 and DD20190011)。
文摘This is a review of the formation and tectonic evolution of the continental Asia in Phanerozoic.The continental Asia has formed on the bases of some pre-Cambrian cratons,such as the Siberia,India,Arabia,North China,Tarim,South China,and Indochina,through multi-stage plate convergence and collisional collages in Phanerozoic.The north-central Asia had experienced the expansion and subduction of the Paleo-Asian Ocean(PAO)in the early Paleozoic and the closure of the PAO in the late Paleozoic and early Mesozoic,forming the PAO regime and Central Asian orogenic belt(CAOB).In the core of the CAOB,the Mongol-Okhotsk Ocean(MOO)opened with limited expansion in the Early Permian and finally closed in the Late Jurassic–Early Cretaceous.The south-central Asia had experienced mainly multi-stage oceanic opening,subduction and collision evolution in the Tethys Ocean,forming the Tethys regime and Himalaya-Tibetan orogenic belt.In eastern Asia,the plate subduction and continental margin orogeny on western margin of the Pacific Ocean,forms the West Pacific regime and West Pacific orogenic belt.The PAO,Tethys,and West Pacific regimes,together with Precambrian cratons among or surrounding them,made up the major tectonic and dynamic systems of the continental Asia in Phanerozoic.Major tectonic events,such as the Early Paleozoic Qilian,Uralian,and Dunhuang orogeneses,the late Paleozoic East Junggar,Tianshan and West Junggar orogeneses,the Middle to Late Permian Ailaoshan orogeny and NorthSouth Lhasa collision,the early Mesozoic Indochina-South China and North-South China collisions,the late Mesozoic Mongolia-Okhotsk orogeny,Lhasa-Qiangtang collision,and intra-continental Yanshanian orogeny,and the Cenozoic IndoAsian,Arab-Asian,and West Pacific margin collisions,constrained the formation and evolution of the continental Asia.The complex dynamic systems have left large number of deformation features,such as large-scale strike-slip faults,thrustfold systems and extensional detachments on the continental Asia.Based on past tectonics,a future supercontinent,the Ameurasia,is prospected for the development of the Asia in ca.250 Myr.
文摘The primary goal of the demonstration project endorsed by the Scientific and Technical Committee for IDNDR in 1992 is to ensure that national agencies are able to assess seismic hazard in a regionally coordinated fashion by using advanced methods.China,as a Regional Center of Central Southern Asia,has contacted with countries of the region to realistically practice seismic hazard assessments of Continental Asia.A test area located in the collision boundary between the Indian and Eurasian plates was chosen to examine the seismic hazard assessment approach in the regional coordinates.The seismotectonics and three versions of seismic sources of the test area are described in this paper and under the Global Seismic Hazard Assessment Program(GSHAP),guidelines an earthquake catalogue of the test area was assembled.Because of the incompleteness of earthquake data in different countries,we adopt different time windows for different magnitude intervals in order to obtain the seismicity parameters of sources.By
文摘Different attempts have been done to deduce the shortening of the Himalayan belt during the India\|Asia convergence. Dewey et al. (1989) and Le Pichon et al.(1992) calculated an India\|Asia shortening of 2300～2150km and 2800～3000km in the western and eastern syntaxes, respectively, since the late 45Ma. According to seafloor\|spreading reconstruction, a total shortening of 3000～500km was estimated after the initial contact of the two plates at 55～50Ma (Molnar and Tapponier, 1975 ; Molnar et al., 1988 ; Replumaz, 1999). Since 40Ma, the part of shortening only accommodated by the Himalayan belt was estimated around 470km in the western part (Coward and Butler, 1985) and 550 to 630km to the east (Ratsbacher et al., 1994 ; Replumaz, 1999). In contrast, global plate reconstructions suggest that the shortening in the Himalaya is of about 1250～250km (Achache et al., 1984 ; Powell et al., 1988 ; Dewey et al.,1989 ; Klootwijk et al., 1992 ; Matte et al., 1997). This discrepancy between the amount of shortening estimated by balancing the Himalayan belt and by plate reconstruction favour the existence of a greater India buried up to 1000km north of the present\|day Indus suture zone and subducted before Middle Eocene time (Klootwijk et al., 1979 ; Patriat and Achache, 1984).
