The mound-making behavior of plateau zokors is one of the most important factors in remodeling meadow microtopography and causing soil erosion in the Yellow River source area of western China,but little is known about...The mound-making behavior of plateau zokors is one of the most important factors in remodeling meadow microtopography and causing soil erosion in the Yellow River source area of western China,but little is known about the effects of microtopography on particle size characteristics(PSC)of eroded sediments from the bare slopes of zokor mounds during different rainfall events.In this study,we analyzed the relationship of microtopographic features derived from laser point cloud data and PSC of eroded sediments at six simulated rainfall intensities(all lasting 60 min).The effects of microtopography on PSC of eroded sediments were studied via partial least squares regression(PLSR)and structural equation modeling(SEM).The results showed that:(1)15-20 minutes from the beginning of rainfall was the sensitive period of soil loss from the slopes,and the function relationship between the rate of sediment and runoff and rainfall intensity can better predict the development trend of soil erosion;(2)Intense erosion occurred mainly in the upper half of the zokor mound,while deposition was mainly limited to its lower half.It is suggested that diminished plateau zokor activity intensity can effectively prevent and control soil erosion;(3)The PSC of eroded sediment is dominated by silt,followed by sand,with clay being the least abundant,and the eroded sediments with a particle size of 10-20μm were sensitive and highly susceptible to rainfall erosion.This finding facilitates the understanding of the formation process of surface geomorphology and the mechanism of soil erosion;(4)The PLSR model indicates that microtopography has an extensive influence on eroded sediments during hydraulic erosion,and the SEM analysis results further confirm that the fractal dimension was the best parameter to represent the PSC of eroded sediments,whereas surface cutting degree was the dominant factor controlling the PSC of eroded sediments.These findings are crucial for predicting soil erosion in the Yellow River source area and provide a new perspective for understanding soil erosion mechanisms in alpine meadow ecosystems.展开更多
In Huojitu Coal Mine of Shendong mining area, the dynamic strata pressure (DSP) accidents occurred when the working faces passed the gully terrain. Focusing on this problem, we used physical simulation experimental me...In Huojitu Coal Mine of Shendong mining area, the dynamic strata pressure (DSP) accidents occurred when the working faces passed the gully terrain. Focusing on this problem, we used physical simulation experimental method to thoroughly study the influence of eroded overlying primary key strata (PKS) in the gully terrain on DSP of shallow coal seams in this paper. The result show that when mining activities took place in the uphill section of shallow coal seams in gully terrain and the PKS were eroded, the blocks could not form stable bond-beam structures since the horizontal force of PKS blocks in adjacent sloping surfaces were relatively small. The sliding instability of blocks caused rapid increase of the load on the sub-key strata (SKS) blocks, which resulted into coal slide and roof fall as well as sharp drop of active columns. This led to DSP phenomenon. When the PKS blocks were intact, there was no DSP phenomenon to enable blocks provide certain horizontal force to maintain stable bond-beam structure. The simulation results were verified by the mining practices of working face 21306 crossing the gully terrain in the Huojitu Coal Mine.展开更多
The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X12...The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.展开更多
During the Pleistocene, the western Qaidam Basin has largely experienced strong structural reconstruction and strong erosion. First, the eroded thickness of Neogene strata was restored approximately by the stratigraph...During the Pleistocene, the western Qaidam Basin has largely experienced strong structural reconstruction and strong erosion. First, the eroded thickness of Neogene strata was restored approximately by the stratigraphic profile comparison method and plane trend surface restoring method; then, accurate calculation of erosion was recovered using vitrinite reflectance, and the erosion that was restored by the trend surface restoring method was corrected; finally, a distribution map of cumulative erosion was produced. This study marks an important achievement in that one of the most important parameters of basin tectonic evolution, sedimentary evolution, and oil and gas accumulation history has been obtained, and that a basic geological problem has been solved in the Qaidam Basin. The areas with high erosion and low erosion are shown in the map and a close relation between the distribution of oil and gas fields and erosion was recognized. Large and medium oil and gas fields are mainly distributed in areas with medium and low erosion. It is difficult to form large-scale oil and gas accumulation in areas in which erosion is more than 2000 m. The mechanism of the relation between oil and gas distribution and erosion is explained. This study will be of use in predicting the distribution of oil and gas.展开更多
Understanding the redistribution of soil organic carbon(OC)driven by erosion contributes to the global carbon budget and watershed management.Quantifying the sources of eroded OC in sediments provides new insights to ...Understanding the redistribution of soil organic carbon(OC)driven by erosion contributes to the global carbon budget and watershed management.Quantifying the sources of eroded OC in sediments provides new insights to addressing this issue.However,limited quantitative information on the factors influencing OC sources has constrained the behavior of regulating the OC exported from the watershed.Here,we explored the sources of OC in lake sediments over the last 100 years and quantified the effects of climate change and human activities on OC sources.Results from the stable isotope fingerprinting and MixSIAR model indicated that phragmites(30.34%)and croplands(21.48%)were consistently the main OC sources.Therefore,efforts should be concentrated on controlling soil erosion from cropland and managing the endogenous environment.In addition,the partial least squares pathways(PLS-PM)and random forests revealed that human activities(Path coefficients(r∂):0.45 to 0.61)have controlled the OC sources over the last hundred years.Agricultural activities,urbanization,and land use change altered the quality of OC sources by affecting the vegetation productivity in source areas.The quantity of OC sources was also influenced by underlying surface and surface connectivity changes.The effects of climate change(temperature(r∂):-0.41 to 0.1;precipitation(r∂):0.1 to 0.29)on OC sources have not been significant,but their long-term effects cannot be ignored.These findings provide a better insight into the origin and behavior of OC in lake sediments under global change,which is crucial for basin management and lake governance.展开更多
With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data fr...With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 22 regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were defined.Almost all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin.展开更多
A soil conservation project was implemented in Tanzania for over 30 years.This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by ...A soil conservation project was implemented in Tanzania for over 30 years.This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by conducting a household survey of 240 households.The study findings show that 89%and 70%of respondents consider soil conservation activities have increased vegetation and soil fertility,respectively.Decreased soil erosion was perceived by 68%of respondents,increased firewood by 98%,increased fodder by 50%,high crop yields by 56%,and food sufficiency by 68%.These are the outcomes of conservation tillage,integrated farming and use of organic fertilizers,controlled stall feeding,agroforestry,construction of cut off drains,contour bunds and contour ridges cultivation,which are the main land use practices in the area.Access to extension services,household sizes,long term land ownership,crop incomes and awareness of soil conservation project were found to determine the level of participation in soil conservation.Major challenges are the lack of sustainability of those activities because of a recent policy decision to withdraw conservation investment.Despite the challenge,this study concluded that past government efforts on soil conservation activities initiated since the early 1970s through decentralization,institutional collaboration,socioeconomic support to farmers and continuous local community participation in restoring the degraded ecosystem of Kondoa have contributed to ensure environmental and socio-economic sustainability in the area.展开更多
基金financially supported by the Qinghai University Graduate Student Research and Practice Innovation Project(2025-GPKY-12)Basic Research Project of Qinghai Provincial Science and Technology Department(2021-ZJ-701)+1 种基金National Natural Science Foundation of China(U23A20159,42161068)the 111 Project of China(D18013)。
文摘The mound-making behavior of plateau zokors is one of the most important factors in remodeling meadow microtopography and causing soil erosion in the Yellow River source area of western China,but little is known about the effects of microtopography on particle size characteristics(PSC)of eroded sediments from the bare slopes of zokor mounds during different rainfall events.In this study,we analyzed the relationship of microtopographic features derived from laser point cloud data and PSC of eroded sediments at six simulated rainfall intensities(all lasting 60 min).The effects of microtopography on PSC of eroded sediments were studied via partial least squares regression(PLSR)and structural equation modeling(SEM).The results showed that:(1)15-20 minutes from the beginning of rainfall was the sensitive period of soil loss from the slopes,and the function relationship between the rate of sediment and runoff and rainfall intensity can better predict the development trend of soil erosion;(2)Intense erosion occurred mainly in the upper half of the zokor mound,while deposition was mainly limited to its lower half.It is suggested that diminished plateau zokor activity intensity can effectively prevent and control soil erosion;(3)The PSC of eroded sediment is dominated by silt,followed by sand,with clay being the least abundant,and the eroded sediments with a particle size of 10-20μm were sensitive and highly susceptible to rainfall erosion.This finding facilitates the understanding of the formation process of surface geomorphology and the mechanism of soil erosion;(4)The PLSR model indicates that microtopography has an extensive influence on eroded sediments during hydraulic erosion,and the SEM analysis results further confirm that the fractal dimension was the best parameter to represent the PSC of eroded sediments,whereas surface cutting degree was the dominant factor controlling the PSC of eroded sediments.These findings are crucial for predicting soil erosion in the Yellow River source area and provide a new perspective for understanding soil erosion mechanisms in alpine meadow ecosystems.
基金The support from both the National Natural Science Foundation of China (No. 50974116)the Open Research Foundation from State Key Laboratory of Coal Resources and Mine Safety at China University of Mining and Technology (No. 08KF04) are gratefully acknowledged
文摘In Huojitu Coal Mine of Shendong mining area, the dynamic strata pressure (DSP) accidents occurred when the working faces passed the gully terrain. Focusing on this problem, we used physical simulation experimental method to thoroughly study the influence of eroded overlying primary key strata (PKS) in the gully terrain on DSP of shallow coal seams in this paper. The result show that when mining activities took place in the uphill section of shallow coal seams in gully terrain and the PKS were eroded, the blocks could not form stable bond-beam structures since the horizontal force of PKS blocks in adjacent sloping surfaces were relatively small. The sliding instability of blocks caused rapid increase of the load on the sub-key strata (SKS) blocks, which resulted into coal slide and roof fall as well as sharp drop of active columns. This led to DSP phenomenon. When the PKS blocks were intact, there was no DSP phenomenon to enable blocks provide certain horizontal force to maintain stable bond-beam structure. The simulation results were verified by the mining practices of working face 21306 crossing the gully terrain in the Huojitu Coal Mine.
文摘The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.
基金co-funded by the National Science and Technology Major Project "Chinese large gas fields' formation conditions,accumulation and objective evaluation"(grant No.2016ZX05007)the Major Special Project of Chinese Petroleum Development Technologies "A study on comprehensive supporting technologies for building oil-gas field of ten million tons in Qaidam Basin"(grant No.2016E-0102)
文摘During the Pleistocene, the western Qaidam Basin has largely experienced strong structural reconstruction and strong erosion. First, the eroded thickness of Neogene strata was restored approximately by the stratigraphic profile comparison method and plane trend surface restoring method; then, accurate calculation of erosion was recovered using vitrinite reflectance, and the erosion that was restored by the trend surface restoring method was corrected; finally, a distribution map of cumulative erosion was produced. This study marks an important achievement in that one of the most important parameters of basin tectonic evolution, sedimentary evolution, and oil and gas accumulation history has been obtained, and that a basic geological problem has been solved in the Qaidam Basin. The areas with high erosion and low erosion are shown in the map and a close relation between the distribution of oil and gas fields and erosion was recognized. Large and medium oil and gas fields are mainly distributed in areas with medium and low erosion. It is difficult to form large-scale oil and gas accumulation in areas in which erosion is more than 2000 m. The mechanism of the relation between oil and gas distribution and erosion is explained. This study will be of use in predicting the distribution of oil and gas.
基金supported by the National Natural Science Foundation of China(U19A2047,42277335)athe Natural Science Foundation of Hunan Province(2022JJ30390).
文摘Understanding the redistribution of soil organic carbon(OC)driven by erosion contributes to the global carbon budget and watershed management.Quantifying the sources of eroded OC in sediments provides new insights to addressing this issue.However,limited quantitative information on the factors influencing OC sources has constrained the behavior of regulating the OC exported from the watershed.Here,we explored the sources of OC in lake sediments over the last 100 years and quantified the effects of climate change and human activities on OC sources.Results from the stable isotope fingerprinting and MixSIAR model indicated that phragmites(30.34%)and croplands(21.48%)were consistently the main OC sources.Therefore,efforts should be concentrated on controlling soil erosion from cropland and managing the endogenous environment.In addition,the partial least squares pathways(PLS-PM)and random forests revealed that human activities(Path coefficients(r∂):0.45 to 0.61)have controlled the OC sources over the last hundred years.Agricultural activities,urbanization,and land use change altered the quality of OC sources by affecting the vegetation productivity in source areas.The quantity of OC sources was also influenced by underlying surface and surface connectivity changes.The effects of climate change(temperature(r∂):-0.41 to 0.1;precipitation(r∂):0.1 to 0.29)on OC sources have not been significant,but their long-term effects cannot be ignored.These findings provide a better insight into the origin and behavior of OC in lake sediments under global change,which is crucial for basin management and lake governance.
基金funded by the Key Project of Chinese National Programs for Fundamental Research and Development (973 Program)"Hydrocarbon accumulation and distribution prediction of typical superimposed basin in China" (grant No. G1999043305)+1 种基金the Key Program of National Natural Science Foundation of China "Studies of continental margin dynamics and hydrocarbon resource potential of the South China Sea" (grant No. 40572067)"Palaeotectonic and palaeogeographic evolution and hydrocarbon accumulation in key changing period of the Paleozoic in the Tarim Basin" (grant No. 41130422)
文摘With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 22 regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were defined.Almost all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin.
基金The study was funded from the World Bank through the Ministry of Livestock Development and Fisheries of Tanzania and the Asian Institute of Technology,Thailand.We thank various organizations,the communities and individuals in the study area for their kind assistance and necessary cooperation during the study.Constructive comments and suggestions of anonymous reviewers highly improved the manuscript quality and their support is greatly appreciated.
文摘A soil conservation project was implemented in Tanzania for over 30 years.This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by conducting a household survey of 240 households.The study findings show that 89%and 70%of respondents consider soil conservation activities have increased vegetation and soil fertility,respectively.Decreased soil erosion was perceived by 68%of respondents,increased firewood by 98%,increased fodder by 50%,high crop yields by 56%,and food sufficiency by 68%.These are the outcomes of conservation tillage,integrated farming and use of organic fertilizers,controlled stall feeding,agroforestry,construction of cut off drains,contour bunds and contour ridges cultivation,which are the main land use practices in the area.Access to extension services,household sizes,long term land ownership,crop incomes and awareness of soil conservation project were found to determine the level of participation in soil conservation.Major challenges are the lack of sustainability of those activities because of a recent policy decision to withdraw conservation investment.Despite the challenge,this study concluded that past government efforts on soil conservation activities initiated since the early 1970s through decentralization,institutional collaboration,socioeconomic support to farmers and continuous local community participation in restoring the degraded ecosystem of Kondoa have contributed to ensure environmental and socio-economic sustainability in the area.
