Restoration of denudation thickness is of great significance to understanding tectonic evolution,hydrocarbon migration and accumulation history in petroliferous basins.How to accurately restore and distinguish denudat...Restoration of denudation thickness is of great significance to understanding tectonic evolution,hydrocarbon migration and accumulation history in petroliferous basins.How to accurately restore and distinguish denudation thicknesses in different periods,however,is difficult.With measurements of vitrinite reflectance(Ro)and interval transit time,along with stratigraphic profile comparison,we restored the total denudation thickness of the Cretaceous in the central Sichuan Basin at a depth range of1100-3300 m.The apatite fission track analysis(AFTA)was employed to identify the denudation periods,namely,the Late Yanshanian,Early Himalayan and the Late Himalayan orogenic epochs,and the ratio of their denudation intensity is about 3.8:1:3.9.The denudation thicknesses at different periods provide an important basis for tectonic evolution and hydrocarbon migration and accumulation.Affected by the diverse denudation intensities,the paleo-structures in the study area feature high in the south and low in the north at the Late Jurassic,high in the north and low in the south at the late Early Cretaceous,high in the southeast and low in the northwest at present in succession.EW-and NE-trending folds and faults are the products of inherited development,which have a controlling effect on hydrocarbon migration and accumulation.展开更多
Determination of one of the components of CO_(2) cycle,i.e.,a chemical denudation,is important from the scientific and practical perspective in the times of greenhouse gas overproduction.The paper presents chemical de...Determination of one of the components of CO_(2) cycle,i.e.,a chemical denudation,is important from the scientific and practical perspective in the times of greenhouse gas overproduction.The paper presents chemical denudation and carbon dioxide consumption calculated with a geochemical modelling method in two catchments located within the Inner Carpathians differing in geological structure and hydrogeological conditions.Carbon dioxide consumption in the catchment of the Biały Stream located in the Tatra Mountains was 132·103 mol/km2/year,and in the catchment of the Suchy Stream located in Podhale it was 189·103 mol/km2/year.The chemical denudation in the catchment of the Biały Stream was 20.0 m3/km2/year,and in the catchment of the Suchy Stream it was 51.9 m3/km2/year.The chemical denudation was calculated using geochemical models.The results were verified by the calculations employing a hydrological method and a direct method.A seasonal variability of the investigated parameters is also demonstrated.In both field-study areas,the chemical denudation was the greatest in the summer months.The highest carbon dioxide consumption per unit volume of a solution was recorded in the winter,and the lowest in the summer.展开更多
The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift ...The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift of ancient plantain surface, river terrace and sedimentary response in peripheral basins of the WYP, suggest that the WYP experienced a rapid uplift and denudation in Quaternary. The WYP have been uplifted about 610～700m, and eroded away about 1095～1600m since Quaternary, average denudation rate reach 0 68～0 94mm/a. Uplift rates in different time interval were calculated according to river terrace. Relations between WYP and Tibetan plateau are discussed further..The Yinggehai basin located at the south termination of the Red River fault, it is the younger (mainly Neogene) pull\|apart basin, which developed at releasing bend of the Red River right\|lateral wrench fault. Since the Neogene, the subsidence center of the Yinggehai basin shifted southward and, connected with the Southeast Hainan basin. Both basins collected large amounts of the Holocene and Quaternary deposits of marine origin. They are peripheral marine basin of the WYP.. Silicate clastic sediments in both basins have been large supported from the WYP into both basins through the Red River system. The total volumes derived from the WYP in the Neogene and Quaternary is 2 8004×10 14 t(1 and 5 1206×10 14 t. The sedimentation rate in Yinggehai basin rose from 0 52mm/a in the Neogene to 1 39mm/a in the Quaternary. The facts that accumulation volume and sedimentation rate rose greatly after the Neogene, suggested a rapid uplift in the WYP. The rapid uplift was responsible for the unconformity between the Neogene and Quaternary. Elevation of ancient planation surface,and river terrace supported the rapid uplift of the WYP also. The ancient planation surface was elevated from 2500～2600m to 3000～3200m during Quaternary, seven terraces in Tue can be traced through the field area in elevation from 20 5m to 612m above the modern river surface in the Lancang River. The Jinsha River also incised into bed rocks about 700m in Shigu. All the facts suggest that southeast margin of Tibet plateau rose rapidly; the plateau was elevated about 610～700m in the Quaternary.展开更多
Qaidam basin is located at northeast Qinghai—Xizang (Tibet) plateau, and surrounded by east Kunlun, south Qilian and Altun mountain systems. The purpose of this paper is to study the Cenozoic basin evolutionary stage...Qaidam basin is located at northeast Qinghai—Xizang (Tibet) plateau, and surrounded by east Kunlun, south Qilian and Altun mountain systems. The purpose of this paper is to study the Cenozoic basin evolutionary stages, structural styles of the Qaidam, and the denudation in adjacent mountain systems through seismic profile interpretation and complemented by field observation. The Qaidam basin has experienced two tectonic stages of Paleogene—early Miocene (65～12Ma) and late Miocene—present (12～0Ma). The former is characterized by differential uplift of the mountains and subsidence of the basin, and the latter by intense compression, wrench, thrusting and folding. The compressional structural styles are mainly distributed in the Circle Hero—Range Depression of southwest Qaidam, such as Nanyishan, Youquanzi, Younan, Youshashan anticline belts and thrust faults. The wrench structural styles of the northern Qaidam include en echelon uplifts (fault—block outcrops) such as Seshitengshan, Luliangshan, Xitieshan and Eimnikshan, which are mainly composed of pre\|Sinian and Paleozoic rocks; en echelon anticlines such as Lenghu—Nanbaxian belts; and en echelon depressions such as Kunteyi, Senan and Yibei depressions, which are mainly composed of Mesozoic and Cenozoic rocks.展开更多
Low-temperature thermochronology is a widely used tool for revealing denudation histories of mountain ranges. Although this technique has been applied mainly to continental orogens, such as the European Alps, Himalaya...Low-temperature thermochronology is a widely used tool for revealing denudation histories of mountain ranges. Although this technique has been applied mainly to continental orogens, such as the European Alps, Himalayas, and Andes, recent technological development of low-temperature thermochronology has made it applicable to a wider variety of mountain ranges with various sizes and tectonic histories. The Japanese Islands comprise young and active island arcs, where an early stage of mountain range formation is observed. Numerous attempts have been made to constrain the uplift and denudation histories of the mountains in the Japanese Islands using geologic, geomorphologic, or geodetic methods. However, the number of thermochronometric attempts has been limited primarily due to the small amount of total denudation since the initiation of the uplift. In this review paper, we introduce the tectonic and geomorphic settings of the mountain ranges in the Japanese Islands, and discuss previous attempts to estimate uplift or denudation of the Japanese mountains using methods other than ther- mochronology. Furthermore, we discuss problems of the thermochronometric applications in revealing denudation histories of the Japanese mountains. Finally, we present a case study of the Kiso Range in central Japan and discuss the current effectiveness and applicability of low-temperature thermochronology to the Japanese mountainous areas.展开更多
This paper synthesized the principal land denudation processes and their role in determining riverine suspended sediment yields(SSY) in two typical geographical environments of the Upper Yangtze River Basin in China a...This paper synthesized the principal land denudation processes and their role in determining riverine suspended sediment yields(SSY) in two typical geographical environments of the Upper Yangtze River Basin in China and the Volga River Basin in Eastern Europe. In the Upper Yangtze River Basin, natural factors including topography, climate,lithology and tectonic activity are responsible for the spatial variation in the magnitude of denudation rates.Human disturbances have contributed to the temporal changes of soil erosion and fluvial SSY during the past decades. On one hand, land use change caused by deforestation and land reclamation has played an important role in the acceleration of sediment production from the central hilly area and lower Jinsha catchment; On the other hand, diverse soil conservation practices(e.g., reforestation,terracing) have contributed to a reduction of soil erosion and sediment production since the late 1980 s.It was difficult to explicitly decouple the effect of mitigation measures in the Lower Jinsha River Basindue to the complexity associated with sediment redistribution within river channels(active channel migration and significant sedimentation). The whole basin can be subdivided into seven sub-regions according to the different proportional inputs of principal denudation processes to riverine SSY. In the Volga River Basin, anthropogenic sheet, rill and gully erosion are the predominant denudation processes in the southern region, while channel bank and bed erosion constitutes the main source of riverine suspended sediment flux in the northern part of the basin. Distribution of cultivated lands significantly determined the intensity of denudation processes.Local relief characteristics also considerably influence soil erosion rates and SSY in the southern Volga River Basin. Lithology, soil cover and climate conditions determined the spatial distribution of sheet, rill and gully erosion intensity, but they play a secondary role in SSY spatial variation.展开更多
The Guadiana Basin is an E-W intraplate Cenozoic basin located in SW of the Iberian Peninsula, covering an area close to 6000 km2. NE-SW Alpine faults divide the basin into two subbasins: the Vegas Altas (VA) to the E...The Guadiana Basin is an E-W intraplate Cenozoic basin located in SW of the Iberian Peninsula, covering an area close to 6000 km2. NE-SW Alpine faults divide the basin into two subbasins: the Vegas Altas (VA) to the East, and the Vegas Bajas (VB) to the West. Sedimentary record consists of <200 m thick of sediments, arranged in two main depositional sequences, DS1 and DS2. Petrographic analysis of sediment sandy-fraction combined with geochemical analysis of <2 mm fraction permit to infer provenance and factors controlling sediment composition. Petrographic analysis of sandy-fraction reveals provenance from basin margins lithologies. In VA subbasin, quartzolithic petrofacies characterized eastern subbasin infill related to the erosion of Neoproterozoic and Palaeozoic metasediments. To the West quartzofeldspathic petrofacies predominates, associated with the erosion of coarse-grained plutonites and short distance transport of their products. Intermediate petrofacies characterizes clastic deposits from the VB. Chemical analysis of clastic deposits corroborates a main felsic origin of sediments with a composition that fits well with the upper crust compositional norm and with the Neoproterozoic Iberian Average Shale (NIBAS). In addition, minor contributions from mafic sources can be identified in DS1 from VB, manifested by anomalies in the content of Co, Ni, Cr, V and Sc. Different stages of weathering (from intermediate to intense) can be deduced by the analysis of both, sandy-fraction petrography and bulk sediment geochemistry. This fact is related to the great hiatus at the base of the Cenozoicbasin infill. Transport-limited denudation regimes can be inferred by the presence of high and intermediate weathered and texturalyinmature sediments. In addition, trace element ratios suggest local enrichment in dense minerals, attributable to recycling processes from metasediments. Finally, the sedimentary record of the Guadiana Basin is constituted by immature sediments formed by limited transsport processes of very variable weathered products from recycled metasedimentary and first-order sediments from granitoids.展开更多
Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by...Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by the major faults at the central segment of the Longmenshan thrust belt, and the vertical faulting history, including the starting time and the total vertical displacement, of the major faults. Then we quantitatively established a complete active process for the central segment of the Longmenshan thrust belt, combining with the previous geophysical data in the deep and geologcial data. This study is critical for deeply and completely understanding the Cenozoic uplift history of the Longmenshan, and also provides thermochronology constraints to the different models for the uplift of the eastern margin of the Tibetan Plateau.展开更多
The Tibetan Plateau is bounded by the Altyn Tagh left-lateral strike-slip fault system in the northwest,unlike the common thrust fault-bounded margins in the south or east.Quantifying surface denudation rate along thi...The Tibetan Plateau is bounded by the Altyn Tagh left-lateral strike-slip fault system in the northwest,unlike the common thrust fault-bounded margins in the south or east.Quantifying surface denudation rate along this enigmatic margin is important for understanding tectonic-geomorphic evolution and deep dynamic processes at margins of the Tibetan Plateau.In this study,we collected modern river sand samples from 29 drainage basins along the eastern section of the Altyn Tagh fault zone and analyzed the concentrations of terrestrial in-situ cosmogenic nuclides26Al and10Be.The26Al-10Be paired-nuclide method is effective in verifying the assumptions of steady-state denudation and short-term sediment transportation time in these basins,thereby ensuring the reliability of derived denudation rates.We found that10Be-derived basin-wide denudation rates range from15 to 610 mm kyr^(-1).Denudation rates are notably enhanced in locations with structural complexities that allow enhanced vertical uplift along this strike-slip fault system,such as restraining double bends and kinematic transition zones of fault junctions,and that the local topography becomes significantly steeper.This finding indicates that local tectonic uplift is the dominant factor governing topographic relief,as well as the intensity and spatial distribution of surface denudation.Basin-wide denudation rates exhibit a non-linear positive correlation with slope gradient,topographic relief,and channel steepness index(k_(sn)),suggesting that topographic indexes constitute robust proxies for estimating denudation rates in this region.Conversely,no discernible correlation was detected between denudation rates and rainfall or vegetation indices.Moreover,the spatial heterogeneity in rock type and thus erodibility exert non-negligible effects on surface denudation and landscape evolution,particularly in areas where tectonic uplift is less dominant.Our study provides for the first time millennial basin-wide denudation rates and their spatial distribution patterns along the northwestern margin of the Tibetan Plateau,and reveals the interplay between surface denudation and tectonic deformation along the Altyn Tagh fault.The results thereby fill an important knowledge gap in understanding surface processes across the poorly-understood plateau's northwestern margin.展开更多
The terrestrial cosmogenic nuclide dataset consisting of 1233^(10)Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate,tectonics and topography on E...The terrestrial cosmogenic nuclide dataset consisting of 1233^(10)Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate,tectonics and topography on Earth-surface denudation processes.^(10)Be-derived basin-wide denudation rates were recalculated using a Monte Carlo simulation approach that relied on pixel-by-pixel production rates.The rates derived span four orders of magnitude,from 7.4±0.7 mm kyr^(-1)(1σ;Central Tibetan Plateau)to 9,646_(-744)^(+777)mm kyr^(-1)(1σ;Southern Tibetan Plateau),with a median of 186 mm kyr^(-1).Comparing our results with the traditional basin-wide production rate scaling model using a centroid coordinate and mean elevation,suggests that 96.6%of production rates will be underestimated using the latter method,especially for basins with a large relief.The bias between both methods reaches as large as 40%,caused by basin hypsometry and the nonlinear scaling of production rate with elevation and latitude.Quantification of the correlations between uniformly recalculated denudation rates and tectonics,climate,topography and rock lithology will facilitate the extrapolation of denudation rates in unknown basins using available data.From the perspective of local scales,precipitation coupled with neotectonics-driven landslides is likely the most influential factor in subtropical Taiwan Island,while topography primarily constrains surface denudation rates in the eastern Tibetan Plateau within a narrow range of precipitation.In highland regions with glacier coverage,such as the Pamir,central and southern Tibetan Plateau high denudation rates are affected by glaciation,whereas lower precipitation and high erosion base level may limit river incision and evolving relief in the Central Tibetan Plateau.In contrast to local-scale findings highlighting a dominant factor constraining denudation rate,our large-scale quantitative analyses across the Asian mountain belts finds that(1)topographic metrics including slope,relief and normalized channel steepness index show similar,first-order,power-law relationships with denudation rates over millennial timescales,as opposed to the linear relationships suggested to control the surface denudation rate;(2)precipitation,temperature,and vegetation cover relative to elevation and a modern tectonic metric of neotectonic activity based on the kernel density distribution of earthquakes,subordinately constrain the surface denudation,approximating a first-order power-law correlation with denudation rate;and(3)the lithology,as represented by an erodibility index,appears not to correlate with denudation rates at the macro-scale of the Asian mountain belts,possibly due to the complex mixture of different types of rocks and the relative low resolution of erodibility index database.展开更多
Pancreatic enucleation is a reasonable surgical procedure for small pancreatic solid pseudopapillary tumors(SPTs).For patients with tumors close to the main pancreatic duct,enucleation surgery was previously considere...Pancreatic enucleation is a reasonable surgical procedure for small pancreatic solid pseudopapillary tumors(SPTs).For patients with tumors close to the main pancreatic duct,enucleation surgery was previously considered contraindicated.We reported a 36-year-old Asian woman with SPT of 1.8×1.5 cm which was in contact with part of the main pancreatic duct,that was once considered contraindicated for enucleation.We adopted the“main pancreatic duct approach”surgical method,and denuded main pancreatic duct with a length of about 2 cm for 360°,to locally resect the tumor,successfully preserving the continuity of the pancreatic duct in this patient.The patient did not complain of discomfort,had no symptoms of indigestion,normal blood sugar levels,and no dilation of the main pancreatic duct was seen on enhanced computed tomography(CT)and enhanced magnetic resonance imaging(MRI)examinations in the first month and third month after surgery.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
Neoproterozoic igneous and metamorphic complexes occur as tectonic domes in the Longmen Mountains of the western margin of the Yangtze Block, and are important in reconstructing the Rodinian supercontinent and constra...Neoproterozoic igneous and metamorphic complexes occur as tectonic domes in the Longmen Mountains of the western margin of the Yangtze Block, and are important in reconstructing the Rodinian supercontinent and constraining the timing and mechanism of tectonic denudational processes. The Pengguan dome consists of granitic intrusions and metamorphic rocks of the Huangshuihe Group and is tectonically overlain by ductilly deformed Sinian to Paleozoic strata. The plutonic intrusions consist of granites with abundant amphibolite enclaves. New LA-ICP-MS zircon U-Pb dating yielded an emplacement age of 809±3 Ma and a protolith age of 844±6 Ma for the granite. The granitic rocks have geochemical signatures typical of A-type granites, indicating their formation under an extensional environment, by melting of newly formed tonalite-trondhjemite-granodiorite (TTG) rocks. A detachment fault, characterized by variable ductile shear deformation of S-C fabric and ESE-ward kinematics, separates the Pengguan dome from the Sinian-Paleozoic cover. 40Ar/39Ar dating of muscovite from the mylonite in the detachment fault of the dome demonstrates that ductile deformation occurred at ~160 Ma. This study indicates the existence of a Neoproterozoic magmatic arc-basin system, which was denudated by a Jurassic middle crustal ductile channel flow along the Longmenshan thrust belt.展开更多
In the crystalline rock region of the Huangling anticline center located in the eastern part of the Three Gorges of the Yangtze River, 6 typical geological topographical section lines were selected and their paleotopo...In the crystalline rock region of the Huangling anticline center located in the eastern part of the Three Gorges of the Yangtze River, 6 typical geological topographical section lines were selected and their paleotopographies were reconstructed. Based on the difference between the present topography and the paleotopography, the denudation thicknesses of different topographical positions could be calculated. According to the principle of denudation correlated with deposition, the initial denudation age of the crystalline rock was inferred from the sedimentary strata deposited in the Jianghan basin near the Huangling anticline, including crystalline rock gravel from the Huangling anticline, which was about 56.5 MaBP. The widespread and intensive denudation took place at about 2.4 MaBP. On the basis of the above-mentioned initial denudation age (56.5 MaBP) and the denudation thicknesses, the denudation rates of different topographical summit levels, different topographical terrace levels and various watershed systems were calculated. The greatest denudation rate is 49.56 mm/ka. The average denudation rate is 16.97 mm/ka in the crystalline rock region of the Huangling anticline.展开更多
Mapping with Ag/Au ratios of mineralized rocks and ores as a parameter reveals that the deep fractures in the Gangdise block control the distribution of the high value regions which may represent the shallow zones of ...Mapping with Ag/Au ratios of mineralized rocks and ores as a parameter reveals that the deep fractures in the Gangdise block control the distribution of the high value regions which may represent the shallow zones of strongly mineralized areas. The variance gradient regions with large Ag/Au ratio may represent the boundaries between strongly mineralized areas and weakly mineralized areas. In the middle part of the Gangdise block, gold and silver mineralization centers mainly distribute along the NW extending Coqen-Xigaze region, NE extending Yangbajain region and E-W extending Lhasa-Gongbogyamda region. The gold and silver mineralized rocks and ores may have been slightly denuded in the west of the middle Gangdise block, and the denudation in the east, however, may be stronger. The primary gold and silver prospect in the west may be better than in the east.展开更多
We studied the effects of angiotensin-converting enzyme inhibitor on the response of arterial intima after balloon denudation.Captopril（3mg.kg/d）was administered to 4miniature pigs after abdominal aortic balloon den...We studied the effects of angiotensin-converting enzyme inhibitor on the response of arterial intima after balloon denudation.Captopril（3mg.kg/d）was administered to 4miniature pigs after abdominal aortic balloon denudation.展开更多
Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover result...Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover results with rapid occurrence of hazardous sinkholes.Monitoring of karst phenomena in Lithuania includes measurements of volumes of karst sinkholes(cubic meters)and amount of dissolved underground gypsum–named chemical gypsum denudation measured by amount cubic meters of gypsum dissolved from 1 square kilometer of karst terrain during one year.展开更多
（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedi...（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedimentary basin, combining with vitrinite reflectance and fission track. （U-Th）/He dating of apatite and zircon from drilling cores in Puguang （普光）-Maoba （毛坝） area and outcrops in Tongjiang （通江） area indicates that the Northeast Sichuan （四川） basin underwent great uplift and denudation during the Tertiary and the Quaternary. During the period, denudation rates changed from 74.8 to 172.5 m/Ma and denudation thickness was between 2 800 and 3 000 m, geotemperature gradually declined into the current temperature, passing through helium closure temperature of apatite. The uplift and denudation relate to new tectonic movement response in the Sichuan basin aroused by the Qinghai （青海）-Tibet plateau. Drilling samples above 4 000 m did not undergo closure temperature of zircon, but the samples nearly 4 000 m might approach closure temperature of zircon and all the samples underwent closure temperature of apatite. According to （U-Th）/He ages of zircon, it is concluded that the Northeast Sichuan basin began to uplift in the Late Jurassic. From the Late Jurassic to the Paleogene, Northeast Sichuan basin was in slow uplift and denudation, but the denudation of Puguang-Maoba area was earlier than that of Tongjiang area. （U-Th）/He ages of zircon indicate the denudation time of provenance areas. On the basis of paleodrainage characteristics, provenance transport and other related data, provenance areas of the clastie rocks are decided, which is worthy to be investigated further.展开更多
基金financially supported by the National Natural Science Foundation of China(42272151)。
文摘Restoration of denudation thickness is of great significance to understanding tectonic evolution,hydrocarbon migration and accumulation history in petroliferous basins.How to accurately restore and distinguish denudation thicknesses in different periods,however,is difficult.With measurements of vitrinite reflectance(Ro)and interval transit time,along with stratigraphic profile comparison,we restored the total denudation thickness of the Cretaceous in the central Sichuan Basin at a depth range of1100-3300 m.The apatite fission track analysis(AFTA)was employed to identify the denudation periods,namely,the Late Yanshanian,Early Himalayan and the Late Himalayan orogenic epochs,and the ratio of their denudation intensity is about 3.8:1:3.9.The denudation thicknesses at different periods provide an important basis for tectonic evolution and hydrocarbon migration and accumulation.Affected by the diverse denudation intensities,the paleo-structures in the study area feature high in the south and low in the north at the Late Jurassic,high in the north and low in the south at the late Early Cretaceous,high in the southeast and low in the northwest at present in succession.EW-and NE-trending folds and faults are the products of inherited development,which have a controlling effect on hydrocarbon migration and accumulation.
基金carried out under the scientific projects of the Ministry of Science and Higher Education No.N N307264133 and NCN No.2011/03/D/ST10/05382.
文摘Determination of one of the components of CO_(2) cycle,i.e.,a chemical denudation,is important from the scientific and practical perspective in the times of greenhouse gas overproduction.The paper presents chemical denudation and carbon dioxide consumption calculated with a geochemical modelling method in two catchments located within the Inner Carpathians differing in geological structure and hydrogeological conditions.Carbon dioxide consumption in the catchment of the Biały Stream located in the Tatra Mountains was 132·103 mol/km2/year,and in the catchment of the Suchy Stream located in Podhale it was 189·103 mol/km2/year.The chemical denudation in the catchment of the Biały Stream was 20.0 m3/km2/year,and in the catchment of the Suchy Stream it was 51.9 m3/km2/year.The chemical denudation was calculated using geochemical models.The results were verified by the calculations employing a hydrological method and a direct method.A seasonal variability of the investigated parameters is also demonstrated.In both field-study areas,the chemical denudation was the greatest in the summer months.The highest carbon dioxide consumption per unit volume of a solution was recorded in the winter,and the lowest in the summer.
文摘The southeast margin of Tibet plateau mainly consists of the Western Yunnan plateau (WYP). The uplift and denudation at the southeast margin of Tibet plateau can be represented by that of the WYP. Based on the uplift of ancient plantain surface, river terrace and sedimentary response in peripheral basins of the WYP, suggest that the WYP experienced a rapid uplift and denudation in Quaternary. The WYP have been uplifted about 610～700m, and eroded away about 1095～1600m since Quaternary, average denudation rate reach 0 68～0 94mm/a. Uplift rates in different time interval were calculated according to river terrace. Relations between WYP and Tibetan plateau are discussed further..The Yinggehai basin located at the south termination of the Red River fault, it is the younger (mainly Neogene) pull\|apart basin, which developed at releasing bend of the Red River right\|lateral wrench fault. Since the Neogene, the subsidence center of the Yinggehai basin shifted southward and, connected with the Southeast Hainan basin. Both basins collected large amounts of the Holocene and Quaternary deposits of marine origin. They are peripheral marine basin of the WYP.. Silicate clastic sediments in both basins have been large supported from the WYP into both basins through the Red River system. The total volumes derived from the WYP in the Neogene and Quaternary is 2 8004×10 14 t(1 and 5 1206×10 14 t. The sedimentation rate in Yinggehai basin rose from 0 52mm/a in the Neogene to 1 39mm/a in the Quaternary. The facts that accumulation volume and sedimentation rate rose greatly after the Neogene, suggested a rapid uplift in the WYP. The rapid uplift was responsible for the unconformity between the Neogene and Quaternary. Elevation of ancient planation surface,and river terrace supported the rapid uplift of the WYP also. The ancient planation surface was elevated from 2500～2600m to 3000～3200m during Quaternary, seven terraces in Tue can be traced through the field area in elevation from 20 5m to 612m above the modern river surface in the Lancang River. The Jinsha River also incised into bed rocks about 700m in Shigu. All the facts suggest that southeast margin of Tibet plateau rose rapidly; the plateau was elevated about 610～700m in the Quaternary.
文摘Qaidam basin is located at northeast Qinghai—Xizang (Tibet) plateau, and surrounded by east Kunlun, south Qilian and Altun mountain systems. The purpose of this paper is to study the Cenozoic basin evolutionary stages, structural styles of the Qaidam, and the denudation in adjacent mountain systems through seismic profile interpretation and complemented by field observation. The Qaidam basin has experienced two tectonic stages of Paleogene—early Miocene (65～12Ma) and late Miocene—present (12～0Ma). The former is characterized by differential uplift of the mountains and subsidence of the basin, and the latter by intense compression, wrench, thrusting and folding. The compressional structural styles are mainly distributed in the Circle Hero—Range Depression of southwest Qaidam, such as Nanyishan, Youquanzi, Younan, Youshashan anticline belts and thrust faults. The wrench structural styles of the northern Qaidam include en echelon uplifts (fault—block outcrops) such as Seshitengshan, Luliangshan, Xitieshan and Eimnikshan, which are mainly composed of pre\|Sinian and Paleozoic rocks; en echelon anticlines such as Lenghu—Nanbaxian belts; and en echelon depressions such as Kunteyi, Senan and Yibei depressions, which are mainly composed of Mesozoic and Cenozoic rocks.
基金supported by a Grantin-Aid for Scientific Research by Japan Society for the Promotion of Science to Hiroyuki Tsutsumi(Grant No.20650155)Grant-inAid for Research by Tokyo Geographical Society to Shigeru Sueoka (research title:uplift and denudation history of the Akaishi Range based on low-temperature thermochronometric methods)
文摘Low-temperature thermochronology is a widely used tool for revealing denudation histories of mountain ranges. Although this technique has been applied mainly to continental orogens, such as the European Alps, Himalayas, and Andes, recent technological development of low-temperature thermochronology has made it applicable to a wider variety of mountain ranges with various sizes and tectonic histories. The Japanese Islands comprise young and active island arcs, where an early stage of mountain range formation is observed. Numerous attempts have been made to constrain the uplift and denudation histories of the mountains in the Japanese Islands using geologic, geomorphologic, or geodetic methods. However, the number of thermochronometric attempts has been limited primarily due to the small amount of total denudation since the initiation of the uplift. In this review paper, we introduce the tectonic and geomorphic settings of the mountain ranges in the Japanese Islands, and discuss previous attempts to estimate uplift or denudation of the Japanese mountains using methods other than ther- mochronology. Furthermore, we discuss problems of the thermochronometric applications in revealing denudation histories of the Japanese mountains. Finally, we present a case study of the Kiso Range in central Japan and discuss the current effectiveness and applicability of low-temperature thermochronology to the Japanese mountainous areas.
基金support for this study was jointly provided by the Chinese Academy of Sciences (No. ZCX2-XB3-09)the Ministry of Science and Technology of China (No. 2011BAD31B03)
文摘This paper synthesized the principal land denudation processes and their role in determining riverine suspended sediment yields(SSY) in two typical geographical environments of the Upper Yangtze River Basin in China and the Volga River Basin in Eastern Europe. In the Upper Yangtze River Basin, natural factors including topography, climate,lithology and tectonic activity are responsible for the spatial variation in the magnitude of denudation rates.Human disturbances have contributed to the temporal changes of soil erosion and fluvial SSY during the past decades. On one hand, land use change caused by deforestation and land reclamation has played an important role in the acceleration of sediment production from the central hilly area and lower Jinsha catchment; On the other hand, diverse soil conservation practices(e.g., reforestation,terracing) have contributed to a reduction of soil erosion and sediment production since the late 1980 s.It was difficult to explicitly decouple the effect of mitigation measures in the Lower Jinsha River Basindue to the complexity associated with sediment redistribution within river channels(active channel migration and significant sedimentation). The whole basin can be subdivided into seven sub-regions according to the different proportional inputs of principal denudation processes to riverine SSY. In the Volga River Basin, anthropogenic sheet, rill and gully erosion are the predominant denudation processes in the southern region, while channel bank and bed erosion constitutes the main source of riverine suspended sediment flux in the northern part of the basin. Distribution of cultivated lands significantly determined the intensity of denudation processes.Local relief characteristics also considerably influence soil erosion rates and SSY in the southern Volga River Basin. Lithology, soil cover and climate conditions determined the spatial distribution of sheet, rill and gully erosion intensity, but they play a secondary role in SSY spatial variation.
文摘The Guadiana Basin is an E-W intraplate Cenozoic basin located in SW of the Iberian Peninsula, covering an area close to 6000 km2. NE-SW Alpine faults divide the basin into two subbasins: the Vegas Altas (VA) to the East, and the Vegas Bajas (VB) to the West. Sedimentary record consists of <200 m thick of sediments, arranged in two main depositional sequences, DS1 and DS2. Petrographic analysis of sediment sandy-fraction combined with geochemical analysis of <2 mm fraction permit to infer provenance and factors controlling sediment composition. Petrographic analysis of sandy-fraction reveals provenance from basin margins lithologies. In VA subbasin, quartzolithic petrofacies characterized eastern subbasin infill related to the erosion of Neoproterozoic and Palaeozoic metasediments. To the West quartzofeldspathic petrofacies predominates, associated with the erosion of coarse-grained plutonites and short distance transport of their products. Intermediate petrofacies characterizes clastic deposits from the VB. Chemical analysis of clastic deposits corroborates a main felsic origin of sediments with a composition that fits well with the upper crust compositional norm and with the Neoproterozoic Iberian Average Shale (NIBAS). In addition, minor contributions from mafic sources can be identified in DS1 from VB, manifested by anomalies in the content of Co, Ni, Cr, V and Sc. Different stages of weathering (from intermediate to intense) can be deduced by the analysis of both, sandy-fraction petrography and bulk sediment geochemistry. This fact is related to the great hiatus at the base of the Cenozoicbasin infill. Transport-limited denudation regimes can be inferred by the presence of high and intermediate weathered and texturalyinmature sediments. In addition, trace element ratios suggest local enrichment in dense minerals, attributable to recycling processes from metasediments. Finally, the sedimentary record of the Guadiana Basin is constituted by immature sediments formed by limited transsport processes of very variable weathered products from recycled metasedimentary and first-order sediments from granitoids.
基金supported by the National Natural Science Foundation of China(grant No.41302159)
文摘Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by the major faults at the central segment of the Longmenshan thrust belt, and the vertical faulting history, including the starting time and the total vertical displacement, of the major faults. Then we quantitatively established a complete active process for the central segment of the Longmenshan thrust belt, combining with the previous geophysical data in the deep and geologcial data. This study is critical for deeply and completely understanding the Cenozoic uplift history of the Longmenshan, and also provides thermochronology constraints to the different models for the uplift of the eastern margin of the Tibetan Plateau.
基金supported by the National Natural Science Foundation of China(Grant Nos.42030305,W2411033)the National Key Research and Development Project(Grant No.2024ZD1001105)the State Key Laboratory of Earthquake Dynamics and Earthquake Prediction(Grant No.LED2022A03)。
文摘The Tibetan Plateau is bounded by the Altyn Tagh left-lateral strike-slip fault system in the northwest,unlike the common thrust fault-bounded margins in the south or east.Quantifying surface denudation rate along this enigmatic margin is important for understanding tectonic-geomorphic evolution and deep dynamic processes at margins of the Tibetan Plateau.In this study,we collected modern river sand samples from 29 drainage basins along the eastern section of the Altyn Tagh fault zone and analyzed the concentrations of terrestrial in-situ cosmogenic nuclides26Al and10Be.The26Al-10Be paired-nuclide method is effective in verifying the assumptions of steady-state denudation and short-term sediment transportation time in these basins,thereby ensuring the reliability of derived denudation rates.We found that10Be-derived basin-wide denudation rates range from15 to 610 mm kyr^(-1).Denudation rates are notably enhanced in locations with structural complexities that allow enhanced vertical uplift along this strike-slip fault system,such as restraining double bends and kinematic transition zones of fault junctions,and that the local topography becomes significantly steeper.This finding indicates that local tectonic uplift is the dominant factor governing topographic relief,as well as the intensity and spatial distribution of surface denudation.Basin-wide denudation rates exhibit a non-linear positive correlation with slope gradient,topographic relief,and channel steepness index(k_(sn)),suggesting that topographic indexes constitute robust proxies for estimating denudation rates in this region.Conversely,no discernible correlation was detected between denudation rates and rainfall or vegetation indices.Moreover,the spatial heterogeneity in rock type and thus erodibility exert non-negligible effects on surface denudation and landscape evolution,particularly in areas where tectonic uplift is less dominant.Our study provides for the first time millennial basin-wide denudation rates and their spatial distribution patterns along the northwestern margin of the Tibetan Plateau,and reveals the interplay between surface denudation and tectonic deformation along the Altyn Tagh fault.The results thereby fill an important knowledge gap in understanding surface processes across the poorly-understood plateau's northwestern margin.
基金supported by the National Natural Science Foundation of China(Grant Nos.42361144879&42303063)the National Key Research and Development Project(Grant No.2020YFA0607700)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0707)the Tianjin Natural Science Foundation(Grant No.22JCQNJC00140)supported by the Science and Technology Innovation Project for Training Leading Talent of Tianjin University。
文摘The terrestrial cosmogenic nuclide dataset consisting of 1233^(10)Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate,tectonics and topography on Earth-surface denudation processes.^(10)Be-derived basin-wide denudation rates were recalculated using a Monte Carlo simulation approach that relied on pixel-by-pixel production rates.The rates derived span four orders of magnitude,from 7.4±0.7 mm kyr^(-1)(1σ;Central Tibetan Plateau)to 9,646_(-744)^(+777)mm kyr^(-1)(1σ;Southern Tibetan Plateau),with a median of 186 mm kyr^(-1).Comparing our results with the traditional basin-wide production rate scaling model using a centroid coordinate and mean elevation,suggests that 96.6%of production rates will be underestimated using the latter method,especially for basins with a large relief.The bias between both methods reaches as large as 40%,caused by basin hypsometry and the nonlinear scaling of production rate with elevation and latitude.Quantification of the correlations between uniformly recalculated denudation rates and tectonics,climate,topography and rock lithology will facilitate the extrapolation of denudation rates in unknown basins using available data.From the perspective of local scales,precipitation coupled with neotectonics-driven landslides is likely the most influential factor in subtropical Taiwan Island,while topography primarily constrains surface denudation rates in the eastern Tibetan Plateau within a narrow range of precipitation.In highland regions with glacier coverage,such as the Pamir,central and southern Tibetan Plateau high denudation rates are affected by glaciation,whereas lower precipitation and high erosion base level may limit river incision and evolving relief in the Central Tibetan Plateau.In contrast to local-scale findings highlighting a dominant factor constraining denudation rate,our large-scale quantitative analyses across the Asian mountain belts finds that(1)topographic metrics including slope,relief and normalized channel steepness index show similar,first-order,power-law relationships with denudation rates over millennial timescales,as opposed to the linear relationships suggested to control the surface denudation rate;(2)precipitation,temperature,and vegetation cover relative to elevation and a modern tectonic metric of neotectonic activity based on the kernel density distribution of earthquakes,subordinately constrain the surface denudation,approximating a first-order power-law correlation with denudation rate;and(3)the lithology,as represented by an erodibility index,appears not to correlate with denudation rates at the macro-scale of the Asian mountain belts,possibly due to the complex mixture of different types of rocks and the relative low resolution of erodibility index database.
文摘Pancreatic enucleation is a reasonable surgical procedure for small pancreatic solid pseudopapillary tumors(SPTs).For patients with tumors close to the main pancreatic duct,enucleation surgery was previously considered contraindicated.We reported a 36-year-old Asian woman with SPT of 1.8×1.5 cm which was in contact with part of the main pancreatic duct,that was once considered contraindicated for enucleation.We adopted the“main pancreatic duct approach”surgical method,and denuded main pancreatic duct with a length of about 2 cm for 360°,to locally resect the tumor,successfully preserving the continuity of the pancreatic duct in this patient.The patient did not complain of discomfort,had no symptoms of indigestion,normal blood sugar levels,and no dilation of the main pancreatic duct was seen on enhanced computed tomography(CT)and enhanced magnetic resonance imaging(MRI)examinations in the first month and third month after surgery.
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.
基金NSFC Innovation Research Group Program (Grant No. 40621002)MOE Innovative Research Team Program (Grant No. IRT0546)+3 种基金the National Natural Science Foundation of China (Grant No. 40472106)the "111" Project (Grant No. B07011)the Project from China Petrochemical Corporation (09-01)Committee on Research and Conference Grants of the University of Hong Kong
文摘Neoproterozoic igneous and metamorphic complexes occur as tectonic domes in the Longmen Mountains of the western margin of the Yangtze Block, and are important in reconstructing the Rodinian supercontinent and constraining the timing and mechanism of tectonic denudational processes. The Pengguan dome consists of granitic intrusions and metamorphic rocks of the Huangshuihe Group and is tectonically overlain by ductilly deformed Sinian to Paleozoic strata. The plutonic intrusions consist of granites with abundant amphibolite enclaves. New LA-ICP-MS zircon U-Pb dating yielded an emplacement age of 809±3 Ma and a protolith age of 844±6 Ma for the granite. The granitic rocks have geochemical signatures typical of A-type granites, indicating their formation under an extensional environment, by melting of newly formed tonalite-trondhjemite-granodiorite (TTG) rocks. A detachment fault, characterized by variable ductile shear deformation of S-C fabric and ESE-ward kinematics, separates the Pengguan dome from the Sinian-Paleozoic cover. 40Ar/39Ar dating of muscovite from the mylonite in the detachment fault of the dome demonstrates that ductile deformation occurred at ~160 Ma. This study indicates the existence of a Neoproterozoic magmatic arc-basin system, which was denudated by a Jurassic middle crustal ductile channel flow along the Longmenshan thrust belt.
文摘In the crystalline rock region of the Huangling anticline center located in the eastern part of the Three Gorges of the Yangtze River, 6 typical geological topographical section lines were selected and their paleotopographies were reconstructed. Based on the difference between the present topography and the paleotopography, the denudation thicknesses of different topographical positions could be calculated. According to the principle of denudation correlated with deposition, the initial denudation age of the crystalline rock was inferred from the sedimentary strata deposited in the Jianghan basin near the Huangling anticline, including crystalline rock gravel from the Huangling anticline, which was about 56.5 MaBP. The widespread and intensive denudation took place at about 2.4 MaBP. On the basis of the above-mentioned initial denudation age (56.5 MaBP) and the denudation thicknesses, the denudation rates of different topographical summit levels, different topographical terrace levels and various watershed systems were calculated. The greatest denudation rate is 49.56 mm/ka. The average denudation rate is 16.97 mm/ka in the crystalline rock region of the Huangling anticline.
基金the National Key Project for Basic Research (G1998040800), the National Natural Science Foundation of China (Grant Nos. 49873013, 40073012) and China Geological Survey (20001020223023).
文摘Mapping with Ag/Au ratios of mineralized rocks and ores as a parameter reveals that the deep fractures in the Gangdise block control the distribution of the high value regions which may represent the shallow zones of strongly mineralized areas. The variance gradient regions with large Ag/Au ratio may represent the boundaries between strongly mineralized areas and weakly mineralized areas. In the middle part of the Gangdise block, gold and silver mineralization centers mainly distribute along the NW extending Coqen-Xigaze region, NE extending Yangbajain region and E-W extending Lhasa-Gongbogyamda region. The gold and silver mineralized rocks and ores may have been slightly denuded in the west of the middle Gangdise block, and the denudation in the east, however, may be stronger. The primary gold and silver prospect in the west may be better than in the east.
文摘We studied the effects of angiotensin-converting enzyme inhibitor on the response of arterial intima after balloon denudation.Captopril（3mg.kg/d）was administered to 4miniature pigs after abdominal aortic balloon denudation.
基金supported by the Ministry of Education,Science and Sport of Republic of Lithuania under the program“An influence of the climate of the climatic and anthropogenic driven factors on the ecosystems and their behaviors,services provided and sustainability of the resources”(20220419/V-585)The monitoring of karst denudation and mapping of sinkholes was funded by Lithuanian Geological Survey under Ministry of Environment,Republic of Lithuania.
文摘Karst phenomena occurring on land surface create sinkholes,ground fissures and other hazardous events.Dissolution of gypsum of Upper Devonian formations in North Lithuania,that occur under thin Quaternary cover results with rapid occurrence of hazardous sinkholes.Monitoring of karst phenomena in Lithuania includes measurements of volumes of karst sinkholes(cubic meters)and amount of dissolved underground gypsum–named chemical gypsum denudation measured by amount cubic meters of gypsum dissolved from 1 square kilometer of karst terrain during one year.
基金supported by the National Basic Research Pro-gram of China (No. 2005CB422102)China Petroleum and Chemical Corporation Program (P06083)
文摘（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedimentary basin, combining with vitrinite reflectance and fission track. （U-Th）/He dating of apatite and zircon from drilling cores in Puguang （普光）-Maoba （毛坝） area and outcrops in Tongjiang （通江） area indicates that the Northeast Sichuan （四川） basin underwent great uplift and denudation during the Tertiary and the Quaternary. During the period, denudation rates changed from 74.8 to 172.5 m/Ma and denudation thickness was between 2 800 and 3 000 m, geotemperature gradually declined into the current temperature, passing through helium closure temperature of apatite. The uplift and denudation relate to new tectonic movement response in the Sichuan basin aroused by the Qinghai （青海）-Tibet plateau. Drilling samples above 4 000 m did not undergo closure temperature of zircon, but the samples nearly 4 000 m might approach closure temperature of zircon and all the samples underwent closure temperature of apatite. According to （U-Th）/He ages of zircon, it is concluded that the Northeast Sichuan basin began to uplift in the Late Jurassic. From the Late Jurassic to the Paleogene, Northeast Sichuan basin was in slow uplift and denudation, but the denudation of Puguang-Maoba area was earlier than that of Tongjiang area. （U-Th）/He ages of zircon indicate the denudation time of provenance areas. On the basis of paleodrainage characteristics, provenance transport and other related data, provenance areas of the clastie rocks are decided, which is worthy to be investigated further.
