Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin t...Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake-related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfoids （micro-corrugated lamination）, fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.展开更多
Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. ...Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. Studies on geotectonic evolution, regional geological characteristics and oreforming and ore-control structures have shown that since the Mesozoic the Da Hinggan Mts. region has entered a typical intercontinental orogenic stage, and it is closely related to mantle branch activities. The south-central segment of the Da Hinggan Mts. is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all of these are the principal factors leading to ore formation and ore control in the region. This paper also further explores the mechanism of mineralization in the south-central segment of the Da Hinggan, summaries the rules of mineralization, puts forward the models of mineralization and points out future ore-exploring orientation.展开更多
Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about...Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about the uplift of the plateau was similar to the first one in tectonic theory, but they consider the time of C3 plant change to C4 in the South Asia, as the time when the plateau reached its highest elevation. This time is 8Ma BP. The third idea, the most Chinese scientists believed, the nearest uplift of the plateau took place since 3 4Ma BP. The occurrence of fault depression and gravel deposit with large thickness in the inner and the marge of the plateau represented the speed uplift. After the collision of the India plate and the Eurasia plateau by the 36Ma, the Tibetean area uplifted several times, but it had been planed to lower area. The plateau with 4500m elevation formed in the Quaternary. While our recent research in the Kunlun Pass area suggest , the nearest uplift occurred at the border of the Early and Middle Pleistocene, and before that time, the elevation of this area was no more than 1500 m.展开更多
The early aged ophiolites have attracted attention of many geologists in recent decades, because the early aged ophiolites can provide the information about the ancient oceanic processes relevant to the evolution of p...The early aged ophiolites have attracted attention of many geologists in recent decades, because the early aged ophiolites can provide the information about the ancient oceanic processes relevant to the evolution of plate tectonics in the early period of the earth, and also concern such problems as whether there existed a ＂Proto-Tethys＂ and the break-up and convergence of the Rodinian Supercontinent. This paper reveals a definite complete ophiolite of Neoproterozoic-Early Paleozoic, named Kuda ophiolite in the western Kunlun Mrs., NW Tibetan Plateau, and reports the recent reasonable SHRIMP zircon U-Pb ages of 510±4 Ma, and 502±13 Ma for the cumulates of the Kuda ophiolite, using the most powerful dating tool, the SHRIMP-Ⅱ. The geochemical and geochronology data integrating with the geological setting suggest that the Kuda ophiolite might have formed in an archipelago oceanic basin, not in a vast ocean, the so-called ＂Proto-Tethys＂, and was tectonically emplaced during the Early Paleozoic.展开更多
The Wugong Mts. region may have experienced three stages of metamorphism in Early Paleo-zoic, which may be closely related to the generations of regional deformation. The first stage ismedium-pressure metamorphism, th...The Wugong Mts. region may have experienced three stages of metamorphism in Early Paleo-zoic, which may be closely related to the generations of regional deformation. The first stage ismedium-pressure metamorphism, the second medium- and high-pressure one with stress on high-pressure metamorphism, and the third low-pressure and high-temperature metamorphism. Theregion, as a whole, is a Caledonian medium-high pressure metamorphic belt.展开更多
The paper aims to present a comparison of visitor behaviors and visitor spatial and temporal distribution in a mountain national park between the pre-Covid-19 period(2017-2019)and Covid-19 pandemic year(2020).The rese...The paper aims to present a comparison of visitor behaviors and visitor spatial and temporal distribution in a mountain national park between the pre-Covid-19 period(2017-2019)and Covid-19 pandemic year(2020).The research is based on pyroelectric sensor data from 2017-2020 and a survey of visitors designed to assess the spatial and temporal distribution of visitors and their behaviors and changes therein.The research data were used to identify two visitor clusters:Impact of Covid-19(IC)and No-Impact of Covid-19(N-IC).The research was conducted in Stolowe Mountains National Park(SMNP)in Poland using data from Monitoring System of tourist traffic(MSTT).A total of 374 respondents participated in the survey in 2020 period,which demonstrated a significant impact of the ongoing pandemic on many aspects of their behavior.These results were compared with the results obtained from 2,642 surveys carried out in 2017-2019.The findings are compared to findings reported by other authors.Some visitors did claim that the pandemic has not affected their behavior in any way.展开更多
The aim of the GPR research was a non-invasive inspection of the root systems arrangement of selected trees(fir Abies alba and spruce Picea abies),in the Silesian Beskids Landscaped Park and Zywiec Beskids Landscaped ...The aim of the GPR research was a non-invasive inspection of the root systems arrangement of selected trees(fir Abies alba and spruce Picea abies),in the Silesian Beskids Landscaped Park and Zywiec Beskids Landscaped Park(Carpathian Mountains,Poland).Field research has been done using RAMAC/GPR with 800 MHz shielded antennas.The survey was conducted by linear profiling to a depth of 2 m.The survey was carried out around the designated trees in 6 meters×6 meters grids.Base points for X(S-N)and Y(W-E)axis were set in corners of each grid.Parallel GPR traverses were conducted within each study area,at intervals of 0.20 m.The maps of the research areas show existing trees and stumps within the GPR sections,with ±1 m error.GPR data analysis was carried out in 2D and 3D systems.Major findings from the GPR survey concluded that the firs(Abies alba),have a "vertical" root system type(with the roots dominant at depths of 0.2-0.8 meters),concentrically away from the tree trunk at a distance of about 1 m to about 2 m,and the spruces(Picea abies),have a "cloud" root system type(at a depth of 10-100 cm),with a few clear,thicker roots extending from the trunk.展开更多
Purpose–This study aims to investigate the fatigue behavior and failure modes of bolted lap joints using Modified Tensile Specimens(MTS)under various cyclic load conditions.Emphasis is placed on identifying the relat...Purpose–This study aims to investigate the fatigue behavior and failure modes of bolted lap joints using Modified Tensile Specimens(MTS)under various cyclic load conditions.Emphasis is placed on identifying the relationship between load amplitude,fatigue life,and damage progression in low-carbon steel assemblies.Design/methodology/approach–An experimental approach was adopted using MTS specimens fabricated from St 1203 cold-rolled steel,joined with Grade 8.8 M4 bolts.Cyclic fatigue tests were conducted under zerobased loading at seven distinct force levels.Fracture surfaces were visually analyzed to identify dominant failure mechanisms.Findings–The results revealed a strong inverse correlation between applied cyclic load and fatigue life.Three distinct failure modes were identified:bolt shear at high loads(5.4 kN),interface cracking and slippage at moderate loads(4.9–5.1 kN),and plate tearing or stable fatigue behavior at lower loads(54.1 kN).The results highlight a progressive transition in failure mechanisms,from bolt shear at high loads to plate tearing and interface cracking at lower loads,providing essential insights for fatigue-resistant bolted joint design.Originality/value–This study offers original insights into the fatigue behavior of bolted lap joints using MTS,a relatively underexplored configuration in fatigue assessment.By experimentally evaluating failure modes under varied cyclic load levels,the authors uncover critical transitions in damage mechanisms—from bolt shear to interface cracking and plate tearing—depending on the applied load.Unlike many existing studies focused on numerical modeling or bonded joints alone,this work provides empirical data rooted in real-world fastening conditions using cold-rolled low-carbon steel.展开更多
剖析了Delphi开发的分布式多层应用系统的架构 ,从MTS COM +组件执行环境的事务控制、提高应用系统的执行性能出发 ,给出了引入MTS COM +协调对象的分布式应用架构 ,并以不同的方式建立MTS COM +执行环境中的数据对象。建造的范例系统 ,...剖析了Delphi开发的分布式多层应用系统的架构 ,从MTS COM +组件执行环境的事务控制、提高应用系统的执行性能出发 ,给出了引入MTS COM +协调对象的分布式应用架构 ,并以不同的方式建立MTS COM +执行环境中的数据对象。建造的范例系统 ,将Delphi 6的MTS COM +数据模块向导、对象向导 ,ADO组件 ,以及MIDAS技术有机地集成为一体。展开更多
基金supported by the National Natural Science Foundation of China(NO,40672080,40621002)the Program for Innovative Research Team in University of the Ministry of Education of China(IRT00546)"111 Project"(Grant No.B08030)
文摘Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake-related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfoids （micro-corrugated lamination）, fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.
基金co-supported by the National Natural Science Foundation Project (No.40872137,40372103)Crisis Mines Study Project (No.20089948)Inner Mongolia Geological Exploring Important Project (No.2004-05)
文摘Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. Studies on geotectonic evolution, regional geological characteristics and oreforming and ore-control structures have shown that since the Mesozoic the Da Hinggan Mts. region has entered a typical intercontinental orogenic stage, and it is closely related to mantle branch activities. The south-central segment of the Da Hinggan Mts. is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all of these are the principal factors leading to ore formation and ore control in the region. This paper also further explores the mechanism of mineralization in the south-central segment of the Da Hinggan, summaries the rules of mineralization, puts forward the models of mineralization and points out future ore-exploring orientation.
文摘Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about the uplift of the plateau was similar to the first one in tectonic theory, but they consider the time of C3 plant change to C4 in the South Asia, as the time when the plateau reached its highest elevation. This time is 8Ma BP. The third idea, the most Chinese scientists believed, the nearest uplift of the plateau took place since 3 4Ma BP. The occurrence of fault depression and gravel deposit with large thickness in the inner and the marge of the plateau represented the speed uplift. After the collision of the India plate and the Eurasia plateau by the 36Ma, the Tibetean area uplifted several times, but it had been planed to lower area. The plateau with 4500m elevation formed in the Quaternary. While our recent research in the Kunlun Pass area suggest , the nearest uplift occurred at the border of the Early and Middle Pleistocene, and before that time, the elevation of this area was no more than 1500 m.
基金This research is financially supported by China Geological Survey(Project No.2003 13000059)the Department of International Cooperation and Science and Technology,Ministry of Land and Resources(Project No.2001010205)the key project of the Ministry of Science and Technology(MOST)(Project No.2001CB711001).
文摘The early aged ophiolites have attracted attention of many geologists in recent decades, because the early aged ophiolites can provide the information about the ancient oceanic processes relevant to the evolution of plate tectonics in the early period of the earth, and also concern such problems as whether there existed a ＂Proto-Tethys＂ and the break-up and convergence of the Rodinian Supercontinent. This paper reveals a definite complete ophiolite of Neoproterozoic-Early Paleozoic, named Kuda ophiolite in the western Kunlun Mrs., NW Tibetan Plateau, and reports the recent reasonable SHRIMP zircon U-Pb ages of 510±4 Ma, and 502±13 Ma for the cumulates of the Kuda ophiolite, using the most powerful dating tool, the SHRIMP-Ⅱ. The geochemical and geochronology data integrating with the geological setting suggest that the Kuda ophiolite might have formed in an archipelago oceanic basin, not in a vast ocean, the so-called ＂Proto-Tethys＂, and was tectonically emplaced during the Early Paleozoic.
文摘The Wugong Mts. region may have experienced three stages of metamorphism in Early Paleo-zoic, which may be closely related to the generations of regional deformation. The first stage ismedium-pressure metamorphism, the second medium- and high-pressure one with stress on high-pressure metamorphism, and the third low-pressure and high-temperature metamorphism. Theregion, as a whole, is a Caledonian medium-high pressure metamorphic belt.
文摘The paper aims to present a comparison of visitor behaviors and visitor spatial and temporal distribution in a mountain national park between the pre-Covid-19 period(2017-2019)and Covid-19 pandemic year(2020).The research is based on pyroelectric sensor data from 2017-2020 and a survey of visitors designed to assess the spatial and temporal distribution of visitors and their behaviors and changes therein.The research data were used to identify two visitor clusters:Impact of Covid-19(IC)and No-Impact of Covid-19(N-IC).The research was conducted in Stolowe Mountains National Park(SMNP)in Poland using data from Monitoring System of tourist traffic(MSTT).A total of 374 respondents participated in the survey in 2020 period,which demonstrated a significant impact of the ongoing pandemic on many aspects of their behavior.These results were compared with the results obtained from 2,642 surveys carried out in 2017-2019.The findings are compared to findings reported by other authors.Some visitors did claim that the pandemic has not affected their behavior in any way.
文摘The aim of the GPR research was a non-invasive inspection of the root systems arrangement of selected trees(fir Abies alba and spruce Picea abies),in the Silesian Beskids Landscaped Park and Zywiec Beskids Landscaped Park(Carpathian Mountains,Poland).Field research has been done using RAMAC/GPR with 800 MHz shielded antennas.The survey was conducted by linear profiling to a depth of 2 m.The survey was carried out around the designated trees in 6 meters×6 meters grids.Base points for X(S-N)and Y(W-E)axis were set in corners of each grid.Parallel GPR traverses were conducted within each study area,at intervals of 0.20 m.The maps of the research areas show existing trees and stumps within the GPR sections,with ±1 m error.GPR data analysis was carried out in 2D and 3D systems.Major findings from the GPR survey concluded that the firs(Abies alba),have a "vertical" root system type(with the roots dominant at depths of 0.2-0.8 meters),concentrically away from the tree trunk at a distance of about 1 m to about 2 m,and the spruces(Picea abies),have a "cloud" root system type(at a depth of 10-100 cm),with a few clear,thicker roots extending from the trunk.
文摘Purpose–This study aims to investigate the fatigue behavior and failure modes of bolted lap joints using Modified Tensile Specimens(MTS)under various cyclic load conditions.Emphasis is placed on identifying the relationship between load amplitude,fatigue life,and damage progression in low-carbon steel assemblies.Design/methodology/approach–An experimental approach was adopted using MTS specimens fabricated from St 1203 cold-rolled steel,joined with Grade 8.8 M4 bolts.Cyclic fatigue tests were conducted under zerobased loading at seven distinct force levels.Fracture surfaces were visually analyzed to identify dominant failure mechanisms.Findings–The results revealed a strong inverse correlation between applied cyclic load and fatigue life.Three distinct failure modes were identified:bolt shear at high loads(5.4 kN),interface cracking and slippage at moderate loads(4.9–5.1 kN),and plate tearing or stable fatigue behavior at lower loads(54.1 kN).The results highlight a progressive transition in failure mechanisms,from bolt shear at high loads to plate tearing and interface cracking at lower loads,providing essential insights for fatigue-resistant bolted joint design.Originality/value–This study offers original insights into the fatigue behavior of bolted lap joints using MTS,a relatively underexplored configuration in fatigue assessment.By experimentally evaluating failure modes under varied cyclic load levels,the authors uncover critical transitions in damage mechanisms—from bolt shear to interface cracking and plate tearing—depending on the applied load.Unlike many existing studies focused on numerical modeling or bonded joints alone,this work provides empirical data rooted in real-world fastening conditions using cold-rolled low-carbon steel.
文摘剖析了Delphi开发的分布式多层应用系统的架构 ,从MTS COM +组件执行环境的事务控制、提高应用系统的执行性能出发 ,给出了引入MTS COM +协调对象的分布式应用架构 ,并以不同的方式建立MTS COM +执行环境中的数据对象。建造的范例系统 ,将Delphi 6的MTS COM +数据模块向导、对象向导 ,ADO组件 ,以及MIDAS技术有机地集成为一体。
