A stratum grouting-soil-structure interaction model which simplified the grouted zone into a series of spherical grout bulbs was established using FLAC3D program. The hypothetical non-uniform expansion process to reac...A stratum grouting-soil-structure interaction model which simplified the grouted zone into a series of spherical grout bulbs was established using FLAC3D program. The hypothetical non-uniform expansion process to reach an assigned volume strain due to soil compression by grouting was achieved by imposing radial velocity on outer mesh nodes of these spheres. This new method avoids the repeated trial calculation needed in the traditional method which applied a fictitious expanding pressure in the grouting element. The deformation and additional internal forces of structure were investigated during each grouting strategy and the influences of various stiffness of grouting proof curtain and bearing capacity of pile tip were discussed simultaneously. The numerical model is proved to be effective to replicate general behavior expected in the field and is capable of modeling the uplifting effect for the surface structure by grouting.展开更多
In order to study the uplifting effect of compensation grouting on ground surface and the upper structures,the ground heave induced by stratum expansion was considered as a stochastic process and the stochastic medium...In order to study the uplifting effect of compensation grouting on ground surface and the upper structures,the ground heave induced by stratum expansion was considered as a stochastic process and the stochastic medium theory was applied to determine the heave and deformation of ground surface under uniform and non-uniform expansion models of spherical grout bulb.The corresponding calculating formulas and simplified methods were derived based on the hypotheses of radial expansion.Then,a numerical model,in which radial velocity was imposed on the outer nodes of grout bulb to simulate the expansion process reaching a required volume strain,was established simultaneously.This new method avoids repeated trial calculation needed in the traditional method which applies a "fictitious" expanding pressure in the grouting elements.The results show that the numerical solutions have good consistency with the theoretical ones.Meanwhile,though the heave resulting from non-uniform expansion is larger than that from uniform expansion for shallow grouting,both of them tend to be convergent with the increasing of grouting depth.展开更多
The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of...The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of the tectonic stress of regions. There should be a prevalent corresponding between terrestrial height and the texture, thermal and stress states of lithosphere. However, there is no a general consensus on what extent different factors affecting the height of a terrain should be up to now, and this is very apparent for the models of plateau uplifting.1\ Debates on the compensatory depth of crustal equilibrium\;Based on a previous equilibrium model, Woollard(1969) set up an equation to show the relation among the crustal thickness ( D \-m), the depth of Mohorovicic discontinuity(M)and height above sea level( H):D \-m=33.2+8.5 H (km). By this equation it is implied that equilibrium compensation has been reached at the depth of Mohorovicic discontinuity for the height of a terrain. As Woollard (1970)described, there is no evidence to show that mass distribution beneath the Mohorovicic discontinuity ever played an important roles in the equilibrium compensation of the crust.展开更多
Prediction of displacement demand to assess seismic performance of structures is a necessary step where nonlinear static procedures are followed.While such predictions have been well established in literature for fixe...Prediction of displacement demand to assess seismic performance of structures is a necessary step where nonlinear static procedures are followed.While such predictions have been well established in literature for fixed-base structures,fewer bodies of researches have been carried out on the effect of rocking and uplifting of shallow foundations supported by soil,on such prediction.This paper aimed to investigate the effect of soil structure interaction on displacement amplification factor C1 using the beam on nonlinear Winkler foundation concept.A practical range of natural period,force reduction factors,and wide range of anticipated behavior from rocking,uplifting and hinging are considered and using thousands nonlinear time history analysis,displacement amplification factors are evaluated.The results indicate that the suggested equations in current rehabilitation documents underestimate displacement demands in the presence of foundation rocking and uplift.Finally,using regression analyses,new equations are proposed to estimate mean values of C1.展开更多
In order to understand how the metallogenic process of porphyry deposit specifically and directly respond to regional uplifting and exhumation,we compiled previous fluid inclusion data of 32 porphyry deposits in China...In order to understand how the metallogenic process of porphyry deposit specifically and directly respond to regional uplifting and exhumation,we compiled previous fluid inclusion data of 32 porphyry deposits in China by recalculating the fluid trapping depths and trapping depth reduction magnitude from early to late mineralization stage veins.The data reveal that the average trapping pressure ratio(Ave TP_(E)/TP_(L))between early-and late-stage veins of the these deposits are 1.2-18.4,mainly in the range of 1.35-5.83,with average trapping pressure reduction(1-Ave TP_(L)/TP_(E))from early-to late-stage veins are 17%-95%,and mainly in the range of 25%-83%.The fluid trapping pressure based mineralization depths most of the porphyry deposits in China had decreased from early to late vein stages by at least 450 m(900-5800 m predominant),or greater than 950 m when take the average depth reduction value,which is greater than the current gap between early-and late-stage veins of each deposit.We propose that the apparently greater mineralization depth reduction magnitude than the current elevation gaps between early and late veins are likely a consequence of synmineralization uplifting and exhumation process that often occurs in porphyry systems.展开更多
Gas expansion caused by significant exhumation in the Sulige gas field in the Ordos Basin since Late Cretaceous and its effects on hydrocarbon accumulation have been investigated systematically based on comprehensive ...Gas expansion caused by significant exhumation in the Sulige gas field in the Ordos Basin since Late Cretaceous and its effects on hydrocarbon accumulation have been investigated systematically based on comprehensive analysis of geochemical,fluid inclusion and production data.The results indicate that gas volume expansion since the Late Cretaceous was the driving force for adjustment and secondary charging of tight sandstone gas reservoirs in the Sulige gas field of the Ordos Basin.The gas retained in the source rocks expanded in volume,resulting in gas re-expulsion,migration and secondary charging into reservoirs,while the gas volume expansion in the tight reservoirs caused the increase of gas saturation,gas-bearing area and gas column height,which worked together to increase the gas content of the reservoir and bring about large-scale gas accumulation events.The Sulige gas field had experienced a two-stage accumulation process,burial before the end of Early Cretaceous and uplifting since the Late Cretaceous.In the burial stage,natural gas was driven by hydrocarbon generation overpressure to migrate and accumulate,while in the uplifting stage,the gas volume expansion drove internal adjustment inside gas reservoirs and secondary charging to form new reservoirs.On the whole,the gas reservoir adjustment and secondary charging during uplifting stage is more significant in the eastern gas field than that in the west,which is favorable for forming gas-rich area.展开更多
Research on the differential uplifting in the Palongzangbu region is crucial to understanding the tectonic deformation mechanism and establishing the model of the faulted blocks in the region of the east structural kn...Research on the differential uplifting in the Palongzangbu region is crucial to understanding the tectonic deformation mechanism and establishing the model of the faulted blocks in the region of the east structural knot.In this paper,based on the ASTER-30m DEM,we calculate the hypsometry index(HI)of 19 watersheds in the Palongzangbu region,and study the differential uplifting in this region combining with seismic data,the ground deposition and erosion process.The result shows that the spatial distribution of the HI value can reflect the differential uplifting in the study area.Differential uplifting exists within different zones,and there are 2 relative strong uplifting centers.One center is near the east structural knot,and the other lies between the Lhari fault and Nujiang fault at their converging segment.Also,the watershed evolution,seismic activity,and ground deposition and erosion process are closely related to each other,and they constitute a chain of evidence which reveals the whole process from the tectonic movement underground to the landform evolution on the surface.展开更多
stone around the neck of humanity. It exists in all na- tions, and governments and civil societies spend much of their time and money trying to address it. While it is no different in China, one aspect of the Chinese ...stone around the neck of humanity. It exists in all na- tions, and governments and civil societies spend much of their time and money trying to address it. While it is no different in China, one aspect of the Chinese anti- poverty campaign stands out. China has committed to eradicating poverty in the next five years.展开更多
Two ^40Ar/^39Ar ages and six fission track ages from monzonite and the Jurassic- Cretaceous rocks provide new geochronologic constraints on the timing of uplifting events in the north margin of the Luxi （鲁西） rise,...Two ^40Ar/^39Ar ages and six fission track ages from monzonite and the Jurassic- Cretaceous rocks provide new geochronologic constraints on the timing of uplifting events in the north margin of the Luxi （鲁西） rise, eastern China. ^40Ar/^39Ar age 111.1±2.4 and 111.2±2.5 Ma of biotite and K-feldspar sampled from the monzonite may record the cooling age at 300 and 150-300 ℃, respectively. Fission track ages of zircon and apatite from the monzonite changing from 75±7 to 40±3 Ma record the cooling age at 250 and 120 ℃, respectively. The apatite from the Jurassic-Cretaceous sandstone and volcanic rocks yielded a different T-t path. The results indicate that there are two phases 111-46.9 and 13.4 （6.5）-0 Ma of rapid uplifting happened to the north margin of the Luxi rise; the first one is a tilted uplift from north to south in Zibo （淄博） during 111-46.9 Ma and in the south in Mengshan （蒙山） during 70-40 Ma; the second one is a tilted uplift from south to north in Mengshan during 32-20 Ma, and in turn in Taishan （泰山） and Zibo during 23-20 and 13.4-0 or 6.5-0 Ma, respectively. The aging coincidence between magmatism and tectonic uplifting implies there are two phases of uplifting induced by large scale extension and lithospheric thinning.展开更多
Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements ex...Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements experienced the same evloutional process: first, the upper crust was pulled apart to form faults; then the Tai-Lu-Yi (Taishan-Lushan-Yishan) fault block occurring in the footwall of the extensional fault was uplifted, which induced the shallow-level detachment movement along the early Precambrian and Palaeozoic unconformity; the ' branching' fault in the upper part of the deep-level detachment layer propagated. As the shallow detachment moved towards the north and the deep one towards the south, the Tai-Lu-Yi fault block acted as the common footwall of both the southern and northern detachment systems. The Tai-Lu-Yi fault block rebounded and uplifted as the overlying material was pulled apart to cause an unloading. Sialic material of the mid-crust below the deep detachment flowed to and accumulated in the free space below the rebounding uplifted body and thickened the body; whereas the mid-crust thinned under the graben systems. The rebounding uplifted body cooled, and then the graben system was occluded, which resulted in the crust-mantle isostatic adjustment and asthenospheric convection. As a result of the two extensional movements, the uplifted central Shandong block with the Tai-Lu-Yi area as the core stands highly above the surrounding plain characterized by graben systems. The present Mount Taishan forms the climax of the uplift.展开更多
Changes in oceanic O-Sr-C isotopic compositions, global cooling and Asian continental aridification beginning in the Middle-Late Eocene(47-34 Ma) are considered to have been caused by the uplift of the Tibetan plateau...Changes in oceanic O-Sr-C isotopic compositions, global cooling and Asian continental aridification beginning in the Middle-Late Eocene(47-34 Ma) are considered to have been caused by the uplift of the Tibetan plateau.The specific timing and uplift mechanism,however,have long been subjects of debate.We investigated the Duogecuoren lavas of the central-western Qiangtang block,which form the largest outcrops among Cenozoic lavas in north-展开更多
The N70°DASA graben is a closed-rift that seems to be the deepest part of the Tim MersoïBasin,which is located in the northwestern part of Niger in West Africa.It contains more than 805 m of Paleozoic-Mesozo...The N70°DASA graben is a closed-rift that seems to be the deepest part of the Tim MersoïBasin,which is located in the northwestern part of Niger in West Africa.It contains more than 805 m of Paleozoic-Mesozoic sediments.The tectonic subsidence and uplifting was calculated by using well log data and deducing the variations in sedimentary thicknesses over time.Geological mapping and tectono-sedimentary analysis indicate that the structural evolution of the DASA trough is characterized by two major periods:(1)the first period was marked by an uplift stage ranging from the Carboniferous to the Permian.It was typified by a weak subsidence rate(3.45 m/Ma on average),under a transpressive tectonic regime,with a decrease in the thickness of the sedimentary series along the axial zone of the trough,and an increase of the thickness towards the border areas;(2)the second period was characterized by a higher subsidence rate(4.11 m/Ma on average)related to a change in the tectonic regime.It was marked by a rifting stage preserved over a long period,subjected to an extensive tectonic regime,from the Triassic to the lower Cretaceous,during which the highest thicknesses of the sedimentary series developed in the axial zone of the graben.The structural and sedimentological features defined the DASA graben as a particular type of syn-sedimentary basin evolving from a transpressive tectonic regime during the Paleozoic to an extensive tectonic regime during the Lower Mesozoic.Thus,the second period marked by an extensional regime would probably be related to the opening of the first stages of the Atlantic Ocean.展开更多
The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains...The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains and provide a timeline for their development.In addition to being an important scientific contribution,this information can be used on guided tours and to promote tourism.The results of eight apatite fission-track analyses suggest three age groups:56,45-30,and 15 Ma.These age groups are related to the uplifting-erosion processes involved in forming ancient multilevel denudation planes at 85-50,45-30,and 24-5 Ma,respectively.The scenic area has experienced three stages of thermal evolution.The first stage occurred before 80 Ma and the third stage after 13 Ma.The three stages had varying cooling rates:2.69,0.62,and 4.23°C/Ma,respectively.Uplifting rates also varied:0.08,0.02,and 0.12 mm/a.The uplifting ranges were also variable:1.14,1.57,and 4.00 km,respectively.Significant uplifting differences between diverse areas are obvious and there were four magnitudes of cumulative uplifting range:4060-3950,3760-3490,3190-3070,and 2650 m.The surface uplifting range varied from 450 to 2230 m.Denudation and uplifting amount averaged 2340 and 3400 m,respectively.The 1060 m difference between them is the average elevation at present.展开更多
According to the synthetic multi-disciplinary study on the lake sediments from core RM of Zoige Basin, i.e. the deepest wholly-collected core in Tibetan Plateau, the palaeoclimate and palaeoenvironment for the basin i...According to the synthetic multi-disciplinary study on the lake sediments from core RM of Zoige Basin, i.e. the deepest wholly-collected core in Tibetan Plateau, the palaeoclimate and palaeoenvironment for the basin in the past 0.9 Ma have been reconstructed. The analytical results suggest that there distinctively exist 3 accelerated uplifting periods for the east Plateau in the past 0.9 Ma, i.e. 800, 360 and 160 kaB.P., with the study on the sedimentary characteristics, the texture of sedimentary cycles and variations of depositional rates, in conjunction with the environment features of cold/warm to dry/wet combination. The paper also probes into the environmental effect under the 3 accelerated tectonic-upliftings on the background of global change.展开更多
The Tianshan Mountains have undergone its initial orogeny, extension adjusting and re-orogeny since the Late Paleozoic. The re-orogeny and uplifting process of the orogeny in the Mesozoic and Cenozoic are two of most ...The Tianshan Mountains have undergone its initial orogeny, extension adjusting and re-orogeny since the Late Paleozoic. The re-orogeny and uplifting process of the orogeny in the Mesozoic and Cenozoic are two of most important events in the geological evo展开更多
During the period from 25 to 17 Ma BP, when the second plateau uplifting, i.e. the second phase of the Himalaya movement, occurred, the Qinghai-Xizang Plateau reached an altitude high enough to chbge the situation of ...During the period from 25 to 17 Ma BP, when the second plateau uplifting, i.e. the second phase of the Himalaya movement, occurred, the Qinghai-Xizang Plateau reached an altitude high enough to chbge the situation of the general circulation. Such an effect of the plateau on the atmospheric circulation was accompanied by the warrning of the tropical ocean, the enhancement of the cross equatorial current, the enlargement of the marginal sea basins in the east-southeastern Asia, the westward extending of the Asian continent and the regression of the Paratethys Sea. As a result, the thermal difference was enlarged, and the air currents were enhanced between continents and oceans; finally the Asian monsoon system, mainly the summer monsoon, was initiated. The former planet wind system was then substituted by the monsoon system, and this caused the important environmental changes, such as the large shrinkage of the dry steppe in Central Asia, and the extension of the humid forest zone in East Asia. Thme changes have been dated at 21.8 Ma BP on the Lingxia profile in the northeastern border of the Tibet Plateau, when the savanna was transformed into the forest.展开更多
In order to obtain the fine structure of Songliao Basin, four nearly vertical reflection profiles were acquired and then processed so as to get the poststack migration sections with two-way travel of 15s. In this pape...In order to obtain the fine structure of Songliao Basin, four nearly vertical reflection profiles were acquired and then processed so as to get the poststack migration sections with two-way travel of 15s. In this paper, we study the reflection characteristics in the southeastern and northeastern uplifting zones of Songliao Basin, discovering that the structure within the up-lifting zones has the following features: (i) The sedimentary thickness decreases from west to east and increases from north to south. (ii) In the northeastern and southeastern uplifting zones, the crustal reflection image varies remarkably along east-west or south-north direction. (iii) In the northeastern uplifting zone, the two-way travel time of Moho interface ranges within 9.6—11.0 s (the depth range of 30—34 km). (iv) In the southeastern uplift, the two-way travel time of Moho interface ranges within 9.7—10.4 s (the depth range of 30—32 km). The poststack migration sections manifest the peculiar phenomenon of the disconnecting Moho reflection phases in Songliao Basin with two-way travel time difference of 0.1—0.5 s (2 km or so). In the vicinity of disconnecting zone, there are several shear faults, which are wide within the uplifting zone and become narrow at the intersection of two uplifting zones. It can be inferred that these reflection images and peculiar reflections from Moho interface are attributed to the coupling of the following dynamic factors: multi-phase weak collision of Heilongjiang micro-continents, westward under-thrusting of Pacific plate and so on.展开更多
There is no final conclusion yet on the uplifting mechanism and epoch of the Tibetan Plateau, which is a hot point of the geological research. This paper discusses the epoch and scales of the hydrothermal activities b...There is no final conclusion yet on the uplifting mechanism and epoch of the Tibetan Plateau, which is a hot point of the geological research. This paper discusses the epoch and scales of the hydrothermal activities based on the ESR ages of hot-spring sediments. The ESR ages show that hydrothermal activities mainly happened in four periods: 50×10~4a, 50×10~4-47×10~4, 40×10~4-35×10~4, 27×10~4-20×10~4 and 10×10~4-0 aB.P.. This conclusion is supported by the geophysical data and the inner plateau and surrounding sediments. Through analyzing the constraints of the deep restraint mechanism and uplift tensile function of the plateau, the uplifting processes of the Tibetan Plateau since 50×10~4a B. P. is elucidated.展开更多
Geological studies show that the southern part of Ailaoshan-Red River shear zone(ALSRRSZ)has experienced complex metallogenic processes and multi-stage non-uniform uplifting,called oblique uplifting since the Cenozoic...Geological studies show that the southern part of Ailaoshan-Red River shear zone(ALSRRSZ)has experienced complex metallogenic processes and multi-stage non-uniform uplifting,called oblique uplifting since the Cenozoic.To detect the deep structure and geodynamic background beneath Daping,Chang’an and other gold and polymetallic deposits in this area,we carried out a high-density short-period seismic array survey in southern Yunnan province.The array used is approximately240 km long with an interval of 500 m between two adjacent stations.Based on the data collected by the array,we used H-κstacking and common conversion point(CCP)methods of receiver functions to reveal the fine crustal structure beneath this array,which was located from Lvchun(western end)to the east and ended in Maguan.The three main conclusions are as follows.(1)The average crustal thickness is approximately 37 km and the Vp/Vsratio is 1.75.However,the thickness and Vp/Vsratio of the Ailao Mountain are rather greater or higher than those of the western Lanping-Simao Basin and eastern South-China block.These results may indicate that the crust is rich in ferromagnesian minerals or has a thermal fluid anomaly after orogenic movement.(2)There are two obvious inclined interfaces beneath the Ailao Mountain in the mid-upper crust,which suggests that strong deformation occurred there during the orogenic period.Some evidences,such as the weak converted-wave Pms phase from the Moho,low P-wave velocities of the upper mantle,high surface heat flow values,and generally developed hot springs,indicate that a strong crust-mantle interaction exists in the southern segments of the Ailaoshan-Red River shear zone.These interactions include a diapir of mantle-sourced magma(stronger in the east than that in the west),lateral collision from the Indian Plate,and the differential uplift caused by the strike-slip movement of the Red River Fault.All of above deep processes led to the Cenozoic oblique uplifting of Ailao Mountain.(3)By combining the location of the deposits on the surface,characteristics of the average crustal Vp/Vsratio,hypocenters of the small earthquakes along the research profile,Moho shape,and horizontal variations of the Pms phase amplitudes,we speculate that the Ailaoshan Fault was the upgoing conduit for metallogenic magma and played a significant role in the Cenozoic development of the multiform metal deposits around the Ailao Mountain area.展开更多
基金Project(2007AA11Z134)supported by the National High Technology Research and Development Program of ChinaProject(10JJ4035)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2010ybfz046)supported by the Fund of Excellent Doctoral Dissertation of Central South University,China
文摘A stratum grouting-soil-structure interaction model which simplified the grouted zone into a series of spherical grout bulbs was established using FLAC3D program. The hypothetical non-uniform expansion process to reach an assigned volume strain due to soil compression by grouting was achieved by imposing radial velocity on outer mesh nodes of these spheres. This new method avoids the repeated trial calculation needed in the traditional method which applied a fictitious expanding pressure in the grouting element. The deformation and additional internal forces of structure were investigated during each grouting strategy and the influences of various stiffness of grouting proof curtain and bearing capacity of pile tip were discussed simultaneously. The numerical model is proved to be effective to replicate general behavior expected in the field and is capable of modeling the uplifting effect for the surface structure by grouting.
基金Project(2007AA11Z134) supported by the National High Technology Research and Development Program of ChinaProject(10JJ4035) supported by the Natural Science Foundation of Hunan Province,China Project(2010ybfz046) supported by the Fund of Excellent Doctoral Dissertation of Central South University,China
文摘In order to study the uplifting effect of compensation grouting on ground surface and the upper structures,the ground heave induced by stratum expansion was considered as a stochastic process and the stochastic medium theory was applied to determine the heave and deformation of ground surface under uniform and non-uniform expansion models of spherical grout bulb.The corresponding calculating formulas and simplified methods were derived based on the hypotheses of radial expansion.Then,a numerical model,in which radial velocity was imposed on the outer nodes of grout bulb to simulate the expansion process reaching a required volume strain,was established simultaneously.This new method avoids repeated trial calculation needed in the traditional method which applies a "fictitious" expanding pressure in the grouting elements.The results show that the numerical solutions have good consistency with the theoretical ones.Meanwhile,though the heave resulting from non-uniform expansion is larger than that from uniform expansion for shallow grouting,both of them tend to be convergent with the increasing of grouting depth.
文摘The distribution of the Mountain ranges, Plateau as well as the distribution of continents and oceans on the earth’s surface are the embodies of the structure and heat states of the materials at the deep crust and of the tectonic stress of regions. There should be a prevalent corresponding between terrestrial height and the texture, thermal and stress states of lithosphere. However, there is no a general consensus on what extent different factors affecting the height of a terrain should be up to now, and this is very apparent for the models of plateau uplifting.1\ Debates on the compensatory depth of crustal equilibrium\;Based on a previous equilibrium model, Woollard(1969) set up an equation to show the relation among the crustal thickness ( D \-m), the depth of Mohorovicic discontinuity(M)and height above sea level( H):D \-m=33.2+8.5 H (km). By this equation it is implied that equilibrium compensation has been reached at the depth of Mohorovicic discontinuity for the height of a terrain. As Woollard (1970)described, there is no evidence to show that mass distribution beneath the Mohorovicic discontinuity ever played an important roles in the equilibrium compensation of the crust.
文摘Prediction of displacement demand to assess seismic performance of structures is a necessary step where nonlinear static procedures are followed.While such predictions have been well established in literature for fixed-base structures,fewer bodies of researches have been carried out on the effect of rocking and uplifting of shallow foundations supported by soil,on such prediction.This paper aimed to investigate the effect of soil structure interaction on displacement amplification factor C1 using the beam on nonlinear Winkler foundation concept.A practical range of natural period,force reduction factors,and wide range of anticipated behavior from rocking,uplifting and hinging are considered and using thousands nonlinear time history analysis,displacement amplification factors are evaluated.The results indicate that the suggested equations in current rehabilitation documents underestimate displacement demands in the presence of foundation rocking and uplift.Finally,using regression analyses,new equations are proposed to estimate mean values of C1.
基金financially supported by National Key R&D Program of China(2018YFC0604101,2018YFC0604106)National Natural Science Foundation of China(41902095)。
文摘In order to understand how the metallogenic process of porphyry deposit specifically and directly respond to regional uplifting and exhumation,we compiled previous fluid inclusion data of 32 porphyry deposits in China by recalculating the fluid trapping depths and trapping depth reduction magnitude from early to late mineralization stage veins.The data reveal that the average trapping pressure ratio(Ave TP_(E)/TP_(L))between early-and late-stage veins of the these deposits are 1.2-18.4,mainly in the range of 1.35-5.83,with average trapping pressure reduction(1-Ave TP_(L)/TP_(E))from early-to late-stage veins are 17%-95%,and mainly in the range of 25%-83%.The fluid trapping pressure based mineralization depths most of the porphyry deposits in China had decreased from early to late vein stages by at least 450 m(900-5800 m predominant),or greater than 950 m when take the average depth reduction value,which is greater than the current gap between early-and late-stage veins of each deposit.We propose that the apparently greater mineralization depth reduction magnitude than the current elevation gaps between early and late veins are likely a consequence of synmineralization uplifting and exhumation process that often occurs in porphyry systems.
基金Supported by the National Natural Science Foundation of China(41502132)China National Demonstration Project(2016ZX05050).
文摘Gas expansion caused by significant exhumation in the Sulige gas field in the Ordos Basin since Late Cretaceous and its effects on hydrocarbon accumulation have been investigated systematically based on comprehensive analysis of geochemical,fluid inclusion and production data.The results indicate that gas volume expansion since the Late Cretaceous was the driving force for adjustment and secondary charging of tight sandstone gas reservoirs in the Sulige gas field of the Ordos Basin.The gas retained in the source rocks expanded in volume,resulting in gas re-expulsion,migration and secondary charging into reservoirs,while the gas volume expansion in the tight reservoirs caused the increase of gas saturation,gas-bearing area and gas column height,which worked together to increase the gas content of the reservoir and bring about large-scale gas accumulation events.The Sulige gas field had experienced a two-stage accumulation process,burial before the end of Early Cretaceous and uplifting since the Late Cretaceous.In the burial stage,natural gas was driven by hydrocarbon generation overpressure to migrate and accumulate,while in the uplifting stage,the gas volume expansion drove internal adjustment inside gas reservoirs and secondary charging to form new reservoirs.On the whole,the gas reservoir adjustment and secondary charging during uplifting stage is more significant in the eastern gas field than that in the west,which is favorable for forming gas-rich area.
基金sponsored by the Study on Regional Tectonically Quiet of Lower Reaches of the Yarlung Zangbo River(A04-2015-003)
文摘Research on the differential uplifting in the Palongzangbu region is crucial to understanding the tectonic deformation mechanism and establishing the model of the faulted blocks in the region of the east structural knot.In this paper,based on the ASTER-30m DEM,we calculate the hypsometry index(HI)of 19 watersheds in the Palongzangbu region,and study the differential uplifting in this region combining with seismic data,the ground deposition and erosion process.The result shows that the spatial distribution of the HI value can reflect the differential uplifting in the study area.Differential uplifting exists within different zones,and there are 2 relative strong uplifting centers.One center is near the east structural knot,and the other lies between the Lhari fault and Nujiang fault at their converging segment.Also,the watershed evolution,seismic activity,and ground deposition and erosion process are closely related to each other,and they constitute a chain of evidence which reveals the whole process from the tectonic movement underground to the landform evolution on the surface.
文摘stone around the neck of humanity. It exists in all na- tions, and governments and civil societies spend much of their time and money trying to address it. While it is no different in China, one aspect of the Chinese anti- poverty campaign stands out. China has committed to eradicating poverty in the next five years.
基金supported by the National Natural Science Foundation of China(Nos.41273060,41072082)
文摘Two ^40Ar/^39Ar ages and six fission track ages from monzonite and the Jurassic- Cretaceous rocks provide new geochronologic constraints on the timing of uplifting events in the north margin of the Luxi （鲁西） rise, eastern China. ^40Ar/^39Ar age 111.1±2.4 and 111.2±2.5 Ma of biotite and K-feldspar sampled from the monzonite may record the cooling age at 300 and 150-300 ℃, respectively. Fission track ages of zircon and apatite from the monzonite changing from 75±7 to 40±3 Ma record the cooling age at 250 and 120 ℃, respectively. The apatite from the Jurassic-Cretaceous sandstone and volcanic rocks yielded a different T-t path. The results indicate that there are two phases 111-46.9 and 13.4 （6.5）-0 Ma of rapid uplifting happened to the north margin of the Luxi rise; the first one is a tilted uplift from north to south in Zibo （淄博） during 111-46.9 Ma and in the south in Mengshan （蒙山） during 70-40 Ma; the second one is a tilted uplift from south to north in Mengshan during 32-20 Ma, and in turn in Taishan （泰山） and Zibo during 23-20 and 13.4-0 or 6.5-0 Ma, respectively. The aging coincidence between magmatism and tectonic uplifting implies there are two phases of uplifting induced by large scale extension and lithospheric thinning.
文摘Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements experienced the same evloutional process: first, the upper crust was pulled apart to form faults; then the Tai-Lu-Yi (Taishan-Lushan-Yishan) fault block occurring in the footwall of the extensional fault was uplifted, which induced the shallow-level detachment movement along the early Precambrian and Palaeozoic unconformity; the ' branching' fault in the upper part of the deep-level detachment layer propagated. As the shallow detachment moved towards the north and the deep one towards the south, the Tai-Lu-Yi fault block acted as the common footwall of both the southern and northern detachment systems. The Tai-Lu-Yi fault block rebounded and uplifted as the overlying material was pulled apart to cause an unloading. Sialic material of the mid-crust below the deep detachment flowed to and accumulated in the free space below the rebounding uplifted body and thickened the body; whereas the mid-crust thinned under the graben systems. The rebounding uplifted body cooled, and then the graben system was occluded, which resulted in the crust-mantle isostatic adjustment and asthenospheric convection. As a result of the two extensional movements, the uplifted central Shandong block with the Tai-Lu-Yi area as the core stands highly above the surrounding plain characterized by graben systems. The present Mount Taishan forms the climax of the uplift.
文摘Changes in oceanic O-Sr-C isotopic compositions, global cooling and Asian continental aridification beginning in the Middle-Late Eocene(47-34 Ma) are considered to have been caused by the uplift of the Tibetan plateau.The specific timing and uplift mechanism,however,have long been subjects of debate.We investigated the Duogecuoren lavas of the central-western Qiangtang block,which form the largest outcrops among Cenozoic lavas in north-
基金The authors are grateful to and acknowledge the efforts of the staff of Global Atomic Corporation for their collaboration.The corresponding author is also grateful to Global Atomic Corporation for their technical and material support.Sincere thanks go to the reviewers for their observations and comments.
文摘The N70°DASA graben is a closed-rift that seems to be the deepest part of the Tim MersoïBasin,which is located in the northwestern part of Niger in West Africa.It contains more than 805 m of Paleozoic-Mesozoic sediments.The tectonic subsidence and uplifting was calculated by using well log data and deducing the variations in sedimentary thicknesses over time.Geological mapping and tectono-sedimentary analysis indicate that the structural evolution of the DASA trough is characterized by two major periods:(1)the first period was marked by an uplift stage ranging from the Carboniferous to the Permian.It was typified by a weak subsidence rate(3.45 m/Ma on average),under a transpressive tectonic regime,with a decrease in the thickness of the sedimentary series along the axial zone of the trough,and an increase of the thickness towards the border areas;(2)the second period was characterized by a higher subsidence rate(4.11 m/Ma on average)related to a change in the tectonic regime.It was marked by a rifting stage preserved over a long period,subjected to an extensive tectonic regime,from the Triassic to the lower Cretaceous,during which the highest thicknesses of the sedimentary series developed in the axial zone of the graben.The structural and sedimentological features defined the DASA graben as a particular type of syn-sedimentary basin evolving from a transpressive tectonic regime during the Paleozoic to an extensive tectonic regime during the Lower Mesozoic.Thus,the second period marked by an extensional regime would probably be related to the opening of the first stages of the Atlantic Ocean.
基金supported by National Natural Science Foundation of China(Grant Nos.40872141,40872068and10475093)the "111" Project(Grant No.B07011)National Basic Research Program of China(Grant No.2009CB421006)
文摘The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains and provide a timeline for their development.In addition to being an important scientific contribution,this information can be used on guided tours and to promote tourism.The results of eight apatite fission-track analyses suggest three age groups:56,45-30,and 15 Ma.These age groups are related to the uplifting-erosion processes involved in forming ancient multilevel denudation planes at 85-50,45-30,and 24-5 Ma,respectively.The scenic area has experienced three stages of thermal evolution.The first stage occurred before 80 Ma and the third stage after 13 Ma.The three stages had varying cooling rates:2.69,0.62,and 4.23°C/Ma,respectively.Uplifting rates also varied:0.08,0.02,and 0.12 mm/a.The uplifting ranges were also variable:1.14,1.57,and 4.00 km,respectively.Significant uplifting differences between diverse areas are obvious and there were four magnitudes of cumulative uplifting range:4060-3950,3760-3490,3190-3070,and 2650 m.The surface uplifting range varied from 450 to 2230 m.Denudation and uplifting amount averaged 2340 and 3400 m,respectively.The 1060 m difference between them is the average elevation at present.
文摘According to the synthetic multi-disciplinary study on the lake sediments from core RM of Zoige Basin, i.e. the deepest wholly-collected core in Tibetan Plateau, the palaeoclimate and palaeoenvironment for the basin in the past 0.9 Ma have been reconstructed. The analytical results suggest that there distinctively exist 3 accelerated uplifting periods for the east Plateau in the past 0.9 Ma, i.e. 800, 360 and 160 kaB.P., with the study on the sedimentary characteristics, the texture of sedimentary cycles and variations of depositional rates, in conjunction with the environment features of cold/warm to dry/wet combination. The paper also probes into the environmental effect under the 3 accelerated tectonic-upliftings on the background of global change.
基金the National Basic Research Program of China (973 Program)(Grant No. 2007CB411305)National Science Foundation of China (Grant No. 40572116)National Project of Geological Survey (Grant No. 200113000078)
文摘The Tianshan Mountains have undergone its initial orogeny, extension adjusting and re-orogeny since the Late Paleozoic. The re-orogeny and uplifting process of the orogeny in the Mesozoic and Cenozoic are two of most important events in the geological evo
基金Project supported by the National Climbing Project and Chinese Academy of Sciences (KZ951-A1-204).
文摘During the period from 25 to 17 Ma BP, when the second plateau uplifting, i.e. the second phase of the Himalaya movement, occurred, the Qinghai-Xizang Plateau reached an altitude high enough to chbge the situation of the general circulation. Such an effect of the plateau on the atmospheric circulation was accompanied by the warrning of the tropical ocean, the enhancement of the cross equatorial current, the enlargement of the marginal sea basins in the east-southeastern Asia, the westward extending of the Asian continent and the regression of the Paratethys Sea. As a result, the thermal difference was enlarged, and the air currents were enhanced between continents and oceans; finally the Asian monsoon system, mainly the summer monsoon, was initiated. The former planet wind system was then substituted by the monsoon system, and this caused the important environmental changes, such as the large shrinkage of the dry steppe in Central Asia, and the extension of the humid forest zone in East Asia. Thme changes have been dated at 21.8 Ma BP on the Lingxia profile in the northeastern border of the Tibet Plateau, when the savanna was transformed into the forest.
文摘In order to obtain the fine structure of Songliao Basin, four nearly vertical reflection profiles were acquired and then processed so as to get the poststack migration sections with two-way travel of 15s. In this paper, we study the reflection characteristics in the southeastern and northeastern uplifting zones of Songliao Basin, discovering that the structure within the up-lifting zones has the following features: (i) The sedimentary thickness decreases from west to east and increases from north to south. (ii) In the northeastern and southeastern uplifting zones, the crustal reflection image varies remarkably along east-west or south-north direction. (iii) In the northeastern uplifting zone, the two-way travel time of Moho interface ranges within 9.6—11.0 s (the depth range of 30—34 km). (iv) In the southeastern uplift, the two-way travel time of Moho interface ranges within 9.7—10.4 s (the depth range of 30—32 km). The poststack migration sections manifest the peculiar phenomenon of the disconnecting Moho reflection phases in Songliao Basin with two-way travel time difference of 0.1—0.5 s (2 km or so). In the vicinity of disconnecting zone, there are several shear faults, which are wide within the uplifting zone and become narrow at the intersection of two uplifting zones. It can be inferred that these reflection images and peculiar reflections from Moho interface are attributed to the coupling of the following dynamic factors: multi-phase weak collision of Heilongjiang micro-continents, westward under-thrusting of Pacific plate and so on.
文摘There is no final conclusion yet on the uplifting mechanism and epoch of the Tibetan Plateau, which is a hot point of the geological research. This paper discusses the epoch and scales of the hydrothermal activities based on the ESR ages of hot-spring sediments. The ESR ages show that hydrothermal activities mainly happened in four periods: 50×10~4a, 50×10~4-47×10~4, 40×10~4-35×10~4, 27×10~4-20×10~4 and 10×10~4-0 aB.P.. This conclusion is supported by the geophysical data and the inner plateau and surrounding sediments. Through analyzing the constraints of the deep restraint mechanism and uplift tensile function of the plateau, the uplifting processes of the Tibetan Plateau since 50×10~4a B. P. is elucidated.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0600302)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0701)the National Natural Science Foundation of China(Grant Nos.41774097,41674064,41704042&41574082)。
文摘Geological studies show that the southern part of Ailaoshan-Red River shear zone(ALSRRSZ)has experienced complex metallogenic processes and multi-stage non-uniform uplifting,called oblique uplifting since the Cenozoic.To detect the deep structure and geodynamic background beneath Daping,Chang’an and other gold and polymetallic deposits in this area,we carried out a high-density short-period seismic array survey in southern Yunnan province.The array used is approximately240 km long with an interval of 500 m between two adjacent stations.Based on the data collected by the array,we used H-κstacking and common conversion point(CCP)methods of receiver functions to reveal the fine crustal structure beneath this array,which was located from Lvchun(western end)to the east and ended in Maguan.The three main conclusions are as follows.(1)The average crustal thickness is approximately 37 km and the Vp/Vsratio is 1.75.However,the thickness and Vp/Vsratio of the Ailao Mountain are rather greater or higher than those of the western Lanping-Simao Basin and eastern South-China block.These results may indicate that the crust is rich in ferromagnesian minerals or has a thermal fluid anomaly after orogenic movement.(2)There are two obvious inclined interfaces beneath the Ailao Mountain in the mid-upper crust,which suggests that strong deformation occurred there during the orogenic period.Some evidences,such as the weak converted-wave Pms phase from the Moho,low P-wave velocities of the upper mantle,high surface heat flow values,and generally developed hot springs,indicate that a strong crust-mantle interaction exists in the southern segments of the Ailaoshan-Red River shear zone.These interactions include a diapir of mantle-sourced magma(stronger in the east than that in the west),lateral collision from the Indian Plate,and the differential uplift caused by the strike-slip movement of the Red River Fault.All of above deep processes led to the Cenozoic oblique uplifting of Ailao Mountain.(3)By combining the location of the deposits on the surface,characteristics of the average crustal Vp/Vsratio,hypocenters of the small earthquakes along the research profile,Moho shape,and horizontal variations of the Pms phase amplitudes,we speculate that the Ailaoshan Fault was the upgoing conduit for metallogenic magma and played a significant role in the Cenozoic development of the multiform metal deposits around the Ailao Mountain area.
