Based on short period Rayleigh wave data recorded by Beliing Seismic Telemetered Network, the dispersion curves of Raleigh wave phase velocity, with period from 2 s to 1 8 s, are calculated by means of two-station met...Based on short period Rayleigh wave data recorded by Beliing Seismic Telemetered Network, the dispersion curves of Raleigh wave phase velocity, with period from 2 s to 1 8 s, are calculated by means of two-station method, for 5 paths across the earthquake zone located in the Beijing graben and the Hebei plain. According to the dispersion features, the upper and middle crustal S wave velocity structures are respectively obtained for the northern segment of Beijing graben and the northern part of Hebei plain. The results show that there is an obvious interface at the depth of g kin in the Beijing graben, the velocity varies little with depth in the middle crust, and there is a low-velocity-zone, with a thickness of 5 km and a buried depth of 14.6 km, in the middle crust of the Hebei plain.展开更多
During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, c...Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, can be identified with each epoch. The geology, stratigraphy, drilling, oil testing and other basic data as well as the measured inclusion and strontium isotope data in the study area are used in the analysis of the formation and evolution process of marine petroliferous reservoirs in the Jianghan Plain area. This study aims to provide a scientific basis for the further exploration of hydrocarbons in the Jianghan Plain and reduce the risks by analyzing the key factors for hydrocarbon accumulation in the marine strata. Our findings show that in the Lower Palaeozoic hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the early period of the Early Yanshanian, and the hydrocarbon reservoir was destroyed in the middle-late period of the Early Yanshanian. In the Lower Triassic-Carboniferous hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the Early Yanshanian, and the hydrocarbon reservoir suffered destruction from the Late Yanshanian to the Early Himalayanian. The preservation conditions of the marine strata in the Jianghan Plain area have been improved since the Late Himalayanian. However, because all source beds have missed the oil/gas generation fastigium and lost the capacity to generate secondary hydrocarbon, no reaccumulation of hydrocarbons can be detected in the study area's marine strata. No industrially exploitable oil/gas reservoir has been discovered in the marine strata of Jianghan Plain area since exploration began in 1958. This study confirms that petroliferous reservoirs in the marine strata have been completely destroyed, and that poor preservation conditions are the primary factor leading to unsuccessful hydrocarbon exploration. It is safely concluded that hydrocarbon exploration in the marine strata of the study area is quite risky.展开更多
Variation of terrestrial water storage in the Hebei plain area from March 2010 to June 2014 was studied using ground gravimetry combined with vertical displacement data from the Global Navigation Satellite System.Resu...Variation of terrestrial water storage in the Hebei plain area from March 2010 to June 2014 was studied using ground gravimetry combined with vertical displacement data from the Global Navigation Satellite System.Results show that observed gravity variation in this area increased continuously,basically reflecting a trend toward land subsidence.With the effect of this subsidence removed,a dominantnegative change in gravity variation was evident,reflecting an average rate of decrease in terrestrial water in this area of 0.10±0.053 m/y,and this is equivalent to a volume of 81.5±43.2×108 m^(3)and is consistent with the spatial distribution of groundwater change from measured hydrologic data.These results can be an essential reference and supplement for the study of terrestrial water variation in the Hebei plain area,and indicate that ground surface gravimetry can be used as an important mean for studying changes in terrestrial water.展开更多
Based on three typical mediums(sandy loam, loam and sandy clay loam) in Hebei Plain, this paper designs phreatic evaporation experiments under different lithology and phreatic depth. Based on the analysis of experimen...Based on three typical mediums(sandy loam, loam and sandy clay loam) in Hebei Plain, this paper designs phreatic evaporation experiments under different lithology and phreatic depth. Based on the analysis of experimental data, the phreatic evaporation law and influencing factors of three mediums were studied. The results showed that:(1) The shallower the phreatic depth, the larger the phreatic evaporation.(2) Sandy clay loam has the biggest response to the increase of the phreatic depth, sandy loam is the second and loam is the smallest.(3) The limit depth of phreatic evaporation of sandy clay loam is about 3 m and that of loam and sandy loam is about 2 m and 3 m, seperately.(4) By fitting the daily evaporation of phreatic water and phreatic depth, the results showed that sandy loam and sandy clay loam are exponential functions and loam is power functions.展开更多
To analyze the genesis of Sr isotopes in groundwater of Hebei plain, time-accumulative effect of ^87Sr/^86Sr ratio was studied. It is shown that ^87Sr/^86Sr ratio increases with the increasing age and depth of groundw...To analyze the genesis of Sr isotopes in groundwater of Hebei plain, time-accumulative effect of ^87Sr/^86Sr ratio was studied. It is shown that ^87Sr/^86Sr ratio increases with the increasing age and depth of groundwater and has a positive correlation to 4Heexc and a negative correlation to δ^18O and δD.The groundwater is divided into three groups to discuss the relation between ^87Sr/^86Sr ratio and Sr^2+ content: ① moderate Sr^2+ content and higher ^87Sr/^86Sr ratio (water Ⅰ); ② lower Sr^2+ content and higher ^87Sr/^86Sr ratio (water Ⅱ); and ③ higher Sr^2+ content and lower ^87Sr/^86Sr ratio (water Ⅲ), that is hot water. On the basis of integrated analysis, it was considered that ① the radiogenic Sr in the Quaternary groundwater (Q4-Q1) originates from weathering of silicate rich in Na and Rb, mainly from plagioclase; ② the radiogenic Sr of hot water in Huanghua port is attributed to carbonate dissolution, with lower ^87Sr/^86Sr ratio and higher Sr/Na ratio; ③ the recharge area is laterally recharged by the groundwater flowing through igneous and metamorphic rocks, with moderate ^87Sr/^86Sr ratio. However, the formation mechanism of Sr isotopes in Tertiary groundwater needs further studies.展开更多
In order to study the distribution and evolution features of saline soil, the correlations between the groundwater depth, salinity and salinization of soil are examined through analyzing the hydrometeorological data a...In order to study the distribution and evolution features of saline soil, the correlations between the groundwater depth, salinity and salinization of soil are examined through analyzing the hydrometeorological data and distribution maps of saline soil, groundwater depth and salinity in 1957 and 2005. The results show that the area of salinization has generally decreased. The area of salinization decreases with the increasing groundwater depth, and the dynamic evolution characteristics appeared between the groundwater depth and area of salinization. The area of heavy salinization is greatest when the groundwater salinity is > 5 g/L, the area of moderate salinization is greatest when the groundwater salinity is between 2-5 g/L, the area of light salinization is greatest when the groundwater salinity is 1-2 g/L and the area of non-salinization is greatest when the groundwater salinity is <1 g/L. The area of heavy salinization was characterized with groundwater depth <2.5 m and salinity >1.8 g/L. The area of non-salinization was characterized with groundwater depth >4.0 m and salinity 0.2-1.5 g/L.展开更多
The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geologic...The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geological setting.Here,in this study,new sporopollen data from three boreholes(GK138,GK111 and GK95)in the coastal plain of Laizhou Bay,Bohai Sea were investigated,and the pollen spectrum since the late middle Pleistocene was established as six sporopollen assemblage zones(Ⅰ-Ⅵ),i.e.,Pinus-Quercus-Artemisia,Gramineae-Artemisia-Chenopodiaceae,Picea-Pinus-QuercusArtemisia,Picea-Pinus-Betula-Gramineae-Artemisia,Picea-Pinus-Cupressaceae-Chenopodiaceae and Pinus-Quercus-Gramineae-Artemisia-Chenopodiaceae.Combining with existing sedimentary successions and detailed radiocarbon dating results of the sediments from the three boreholes,paleovegetation and climatic evolution since the late middle Pleistocene were reconstructed.The findings revealed that climatic changes in this area since the late middle Pleistocene were characterized by alternating cold-arid and warmhumid conditions,which were well correlated with marine isotopic stages(MIS).The present study offers specific insight into the climatic dynamics in the North China Plain since the late middle Pleistocene and provides evidence of a clear link among the palynoflora in the area,the glacial-interglacial period climatedriven sea-level changes,and the marineδ^(18)O records.展开更多
Ground fissure hazards frequently emerge in Hebei Plain, which damage roads, dams, buildings and farmland. The paper reviews and analyses current state of knowledge and research into ground fissure and geological envi...Ground fissure hazards frequently emerge in Hebei Plain, which damage roads, dams, buildings and farmland. The paper reviews and analyses current state of knowledge and research into ground fissure and geological environment in Hebei Plain. It is shown that the level of research and investigation is in some aspects insufficient. Knowledge is lacking in the use of corresponding geological concept models for specific ground fissures, three-dimensional numerical simulations of ground fissures caused by pumping through soil with pre-existing fractures, numerical simulations of ground fissures caused by dislocation in intersection faults, and the failure criterion and the constitutive relationship of rock and soil. Furthermore, we put forward geological concept models for ground fissure formation following the dislocation of a buried intersection fault, over-exploitation of groundwater and its compound origin mechanisms in order to provide scientific evidence for the quantitative analysis.展开更多
Based on the groundwater resources evaluation, the groundwater exploitation potentiality evaluation is aiming at providing references for management, planning and development of groundwater. Traditional evaluation met...Based on the groundwater resources evaluation, the groundwater exploitation potentiality evaluation is aiming at providing references for management, planning and development of groundwater. Traditional evaluation methods mainly adopted individual indicator as a method which cannot fully reflect the affecting factors of the groundwater exploitation potential in a scientific way. The idea that the spatial distribution and dynamic change of groundwater is not only affected by socio-economic development and exploitation technology but also influenced by its regulation is coincided with the niche theory. This paper has preliminarily applied the niche theory to groundwater exploitation potential analysis, and proposed the concept of groundwater niche as well as its related definition, connotation and calculation formula. Meanwhile, by taking the Hebei Plain as an example, the article has made an evaluation of groundwater exploitation potentiality and a contrast with the results of the traditional evaluation methods on the construction of groundwater niche index system, and then verified the feasibility and rationality of this index system. It turns out that, it is truly comprehensive, scientific and rational to make groundwater niche calculation and exploitation potential analysis by using the evaluation index system. Niche theory has provided a new and fundamental attempt for the analysis and competition strategy for the groundwater exploitation potentiality evaluation.展开更多
Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological we...Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological wet fronts were different. The sandy loam had the fastest migration rate, the loam followed, and the clay loam was the slowest, but the law of change is the same among the three lithologies. The volumetric water content affects the change of Boltzmann parameter λ. When the volumetric water content is between 0.35-0.45 cm^3/cm^3,λ approaches stability. When the volumetric water content is less than 0.35 cm^3/cm^3, the λ value decreases rapidly with the decrease of water content. The water diffusion rate is related to the volumetric water content and particle size. The greater the moisture content is, the greater the diffusion rate will be. The larger the particle size, the larger the diffusion rate. The diffusivity of sandy loam is 10-30 times larger than that of loam and clay loam. The relationship between water content and diffusion rate is in accordance with the exponential function .展开更多
Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet a...Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet analysis in this article. The periodic oscillation of rainfall variation and the points of abrupt change at different time scales along the time series are dis-covered. According to the main periods, the trend of rainfall variation in the future has also been estimated. The results indicate that there are obvious periodic oscillations of 8―12 years and 4―6 years for the seasonal and annual rainfalls variation. The variation trend of the summer rainfall is in agreement with that of the annual rainfall and both of them have the main periods of 1 year and 12 years. It is estimated, based on the main period of 1 year, that the amount of rainfall will be relatively small around 2003 and abundant around 2004―2007 in the Hebei Plain.展开更多
This study firstly analyzed the shrinkage of winter wheat and the changes of crop- ping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, inclu...This study firstly analyzed the shrinkage of winter wheat and the changes of crop- ping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calcu- lated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are as follows. 1) The sown areas of winter wheat in the 11 cities in the Hebei Plain all shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×10^4 ha. The shrinkage was most serious in the Bei- jing-Tianjin-Tangshan metropolitan agglomerate, with a shrinkage rate of 47.23%. 2) The precipitation fill rate of winter wheat was only 20%-30%, while those of spring maize and summer maize both exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged only from 160 mm to 210 ram. 3) The water resources conserved as a result of the winter wheat sown area shrinkage during the study period were about 15.96×10^8 m^3/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Mid-Route of the South-to-North Water Diversion Project.展开更多
It becomes an increasing concern that groundwater quality in exploited deep confined aquifer may deteriorate due to brackish water leakage from its overlying saline aquifer in Hebei Plain. However, the monitoring data...It becomes an increasing concern that groundwater quality in exploited deep confined aquifer may deteriorate due to brackish water leakage from its overlying saline aquifer in Hebei Plain. However, the monitoring data show that the TDS does not significantly change in the exploited aquifer. Some physics or chemistry processes must have taken place in aquitards during brackish leakage. The semi-permeable membrane function of clay aquitard during the process of hyperfiltration(reverse osmosis) should be one of the most important processes. To confirm and test this hyperfiltration mechanism, a series of experiments were performed in which Na Cl solutions were hydraulically forced through different clay sampled from aquitard. The solution 7 g/L in NaC l was forced through at 20 °C by a fluid pressure of 0.5 kN. The results show that hyperfiltration indeed happens in caly aquitard. Semi-permeability is quantified by the reflection coefficient σ. The mean rejection coefficients(σ) for clay samples #1, #2 and #3 were estimated to be 0.063, 0.164 and 0.040, respectively. This behavior of clay was well explained with the theory of the diffuse double layer. The hyperfiltration effect is to the great extent responsible for the chemical process in the aquitard.展开更多
Groundwater is the main water source in the Hebei Plain. Evolution of groundwater chemistry can not only provide scientific data for sustainable usage of groundwater resources, but also help us in better understanding...Groundwater is the main water source in the Hebei Plain. Evolution of groundwater chemistry can not only provide scientific data for sustainable usage of groundwater resources, but also help us in better understanding hydrogeochemical processes in aquifers. Spatial distribution and temporal evolution were analyzed on basis of monitoring data between 1975 and 2005. Results showed that major components in groundwater had increasing trends since 1970s. Major components in shallow groundwater increased more than those in deep one. In shallow groundwater of piedmont alluvial fan-recharge zone, concentrations of Na+, Ca2+, SO42- had great increasing trends, while other major components increased by less than 30%. There were great increasing trends in Na+, Cl-, SO42- concentrations in deep groundwater of central alluvial plain-intermediate zone, while other major components increased by no more than 20%. Deep groundwater from coast plain-discharge zone and piedmont alluvial fan-recharge zone showed no significant variations in major ion concentrations. In shallow groundwater, dissolution, evaporation and human activities played a major role in the increase in major components. However, groundwater mixture resulting from deep groundwater exploitation was believed to be the major factors for the increases in major components in deep groundwater of central alluvial plain-intermediate zone.展开更多
文摘Based on short period Rayleigh wave data recorded by Beliing Seismic Telemetered Network, the dispersion curves of Raleigh wave phase velocity, with period from 2 s to 1 8 s, are calculated by means of two-station method, for 5 paths across the earthquake zone located in the Beijing graben and the Hebei plain. According to the dispersion features, the upper and middle crustal S wave velocity structures are respectively obtained for the northern segment of Beijing graben and the northern part of Hebei plain. The results show that there is an obvious interface at the depth of g kin in the Beijing graben, the velocity varies little with depth in the middle crust, and there is a low-velocity-zone, with a thickness of 5 km and a buried depth of 14.6 km, in the middle crust of the Hebei plain.
基金supported by the Major State Basic Research Development Program of China (973 Program No: 2012CB416601)+1 种基金the National Natural Science Foundation of China (No: 41322018) projectsthe National High-Level Talents Special Support Plan
文摘During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
基金the subsidization of a Major Project of Chinese National Programs for Fundamental Research and Development (973 Program, No. 2012CB214805)supported by the Chinese National Natural Science Foundation (No. 41372141)
文摘Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, can be identified with each epoch. The geology, stratigraphy, drilling, oil testing and other basic data as well as the measured inclusion and strontium isotope data in the study area are used in the analysis of the formation and evolution process of marine petroliferous reservoirs in the Jianghan Plain area. This study aims to provide a scientific basis for the further exploration of hydrocarbons in the Jianghan Plain and reduce the risks by analyzing the key factors for hydrocarbon accumulation in the marine strata. Our findings show that in the Lower Palaeozoic hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the early period of the Early Yanshanian, and the hydrocarbon reservoir was destroyed in the middle-late period of the Early Yanshanian. In the Lower Triassic-Carboniferous hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the Early Yanshanian, and the hydrocarbon reservoir suffered destruction from the Late Yanshanian to the Early Himalayanian. The preservation conditions of the marine strata in the Jianghan Plain area have been improved since the Late Himalayanian. However, because all source beds have missed the oil/gas generation fastigium and lost the capacity to generate secondary hydrocarbon, no reaccumulation of hydrocarbons can be detected in the study area's marine strata. No industrially exploitable oil/gas reservoir has been discovered in the marine strata of Jianghan Plain area since exploration began in 1958. This study confirms that petroliferous reservoirs in the marine strata have been completely destroyed, and that poor preservation conditions are the primary factor leading to unsuccessful hydrocarbon exploration. It is safely concluded that hydrocarbon exploration in the marine strata of the study area is quite risky.
基金supported by the Director Foundation of Institute of Seismology,China Earthquake Administration(Grant Nos:IS201726121)the National Natural Science Foundation of China(Grant Nos:41304059)the special earthquake research grant offered by China Earthquake Administration(Grant Nos:201308009,201508009)。
文摘Variation of terrestrial water storage in the Hebei plain area from March 2010 to June 2014 was studied using ground gravimetry combined with vertical displacement data from the Global Navigation Satellite System.Results show that observed gravity variation in this area increased continuously,basically reflecting a trend toward land subsidence.With the effect of this subsidence removed,a dominantnegative change in gravity variation was evident,reflecting an average rate of decrease in terrestrial water in this area of 0.10±0.053 m/y,and this is equivalent to a volume of 81.5±43.2×108 m^(3)and is consistent with the spatial distribution of groundwater change from measured hydrologic data.These results can be an essential reference and supplement for the study of terrestrial water variation in the Hebei plain area,and indicate that ground surface gravimetry can be used as an important mean for studying changes in terrestrial water.
基金supported by the basic research fund of the GAGS(YYWF201624)Hebei graduate's innovative funding(CXZZSS20181)
文摘Based on three typical mediums(sandy loam, loam and sandy clay loam) in Hebei Plain, this paper designs phreatic evaporation experiments under different lithology and phreatic depth. Based on the analysis of experimental data, the phreatic evaporation law and influencing factors of three mediums were studied. The results showed that:(1) The shallower the phreatic depth, the larger the phreatic evaporation.(2) Sandy clay loam has the biggest response to the increase of the phreatic depth, sandy loam is the second and loam is the smallest.(3) The limit depth of phreatic evaporation of sandy clay loam is about 3 m and that of loam and sandy loam is about 2 m and 3 m, seperately.(4) By fitting the daily evaporation of phreatic water and phreatic depth, the results showed that sandy loam and sandy clay loam are exponential functions and loam is power functions.
基金This paper is supported by China Geological Survey Project (No. 200320150002).
文摘To analyze the genesis of Sr isotopes in groundwater of Hebei plain, time-accumulative effect of ^87Sr/^86Sr ratio was studied. It is shown that ^87Sr/^86Sr ratio increases with the increasing age and depth of groundwater and has a positive correlation to 4Heexc and a negative correlation to δ^18O and δD.The groundwater is divided into three groups to discuss the relation between ^87Sr/^86Sr ratio and Sr^2+ content: ① moderate Sr^2+ content and higher ^87Sr/^86Sr ratio (water Ⅰ); ② lower Sr^2+ content and higher ^87Sr/^86Sr ratio (water Ⅱ); and ③ higher Sr^2+ content and lower ^87Sr/^86Sr ratio (water Ⅲ), that is hot water. On the basis of integrated analysis, it was considered that ① the radiogenic Sr in the Quaternary groundwater (Q4-Q1) originates from weathering of silicate rich in Na and Rb, mainly from plagioclase; ② the radiogenic Sr of hot water in Huanghua port is attributed to carbonate dissolution, with lower ^87Sr/^86Sr ratio and higher Sr/Na ratio; ③ the recharge area is laterally recharged by the groundwater flowing through igneous and metamorphic rocks, with moderate ^87Sr/^86Sr ratio. However, the formation mechanism of Sr isotopes in Tertiary groundwater needs further studies.
基金funded by 973 Program Special Item (2010CB428805-1)
文摘In order to study the distribution and evolution features of saline soil, the correlations between the groundwater depth, salinity and salinization of soil are examined through analyzing the hydrometeorological data and distribution maps of saline soil, groundwater depth and salinity in 1957 and 2005. The results show that the area of salinization has generally decreased. The area of salinization decreases with the increasing groundwater depth, and the dynamic evolution characteristics appeared between the groundwater depth and area of salinization. The area of heavy salinization is greatest when the groundwater salinity is > 5 g/L, the area of moderate salinization is greatest when the groundwater salinity is between 2-5 g/L, the area of light salinization is greatest when the groundwater salinity is 1-2 g/L and the area of non-salinization is greatest when the groundwater salinity is <1 g/L. The area of heavy salinization was characterized with groundwater depth <2.5 m and salinity >1.8 g/L. The area of non-salinization was characterized with groundwater depth >4.0 m and salinity 0.2-1.5 g/L.
基金supported by the Taishan Scholar Foundation of Shandong Province,China(Grant No.20190954)the National Natural Science Foundation of China(Grant No.32101373)+1 种基金the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2020QC050)the State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,CAS,China(Grant No.123104)。
文摘The coastal plain of Laizhou Bay in Bohai Sea is a transitional area of land-sea interaction.Sediments in this area can bear significant information of sea-level fluctuation,climate change,as well as regional geological setting.Here,in this study,new sporopollen data from three boreholes(GK138,GK111 and GK95)in the coastal plain of Laizhou Bay,Bohai Sea were investigated,and the pollen spectrum since the late middle Pleistocene was established as six sporopollen assemblage zones(Ⅰ-Ⅵ),i.e.,Pinus-Quercus-Artemisia,Gramineae-Artemisia-Chenopodiaceae,Picea-Pinus-QuercusArtemisia,Picea-Pinus-Betula-Gramineae-Artemisia,Picea-Pinus-Cupressaceae-Chenopodiaceae and Pinus-Quercus-Gramineae-Artemisia-Chenopodiaceae.Combining with existing sedimentary successions and detailed radiocarbon dating results of the sediments from the three boreholes,paleovegetation and climatic evolution since the late middle Pleistocene were reconstructed.The findings revealed that climatic changes in this area since the late middle Pleistocene were characterized by alternating cold-arid and warmhumid conditions,which were well correlated with marine isotopic stages(MIS).The present study offers specific insight into the climatic dynamics in the North China Plain since the late middle Pleistocene and provides evidence of a clear link among the palynoflora in the area,the glacial-interglacial period climatedriven sea-level changes,and the marineδ^(18)O records.
基金supported by 973 ProgramSpecial Item(2010CB428805-1)the National Natural Science Foundation Project(41102138)
文摘Ground fissure hazards frequently emerge in Hebei Plain, which damage roads, dams, buildings and farmland. The paper reviews and analyses current state of knowledge and research into ground fissure and geological environment in Hebei Plain. It is shown that the level of research and investigation is in some aspects insufficient. Knowledge is lacking in the use of corresponding geological concept models for specific ground fissures, three-dimensional numerical simulations of ground fissures caused by pumping through soil with pre-existing fractures, numerical simulations of ground fissures caused by dislocation in intersection faults, and the failure criterion and the constitutive relationship of rock and soil. Furthermore, we put forward geological concept models for ground fissure formation following the dislocation of a buried intersection fault, over-exploitation of groundwater and its compound origin mechanisms in order to provide scientific evidence for the quantitative analysis.
基金supported by the Graduate Student Innovation Fund of Hebei Province (No.197)
文摘Based on the groundwater resources evaluation, the groundwater exploitation potentiality evaluation is aiming at providing references for management, planning and development of groundwater. Traditional evaluation methods mainly adopted individual indicator as a method which cannot fully reflect the affecting factors of the groundwater exploitation potential in a scientific way. The idea that the spatial distribution and dynamic change of groundwater is not only affected by socio-economic development and exploitation technology but also influenced by its regulation is coincided with the niche theory. This paper has preliminarily applied the niche theory to groundwater exploitation potential analysis, and proposed the concept of groundwater niche as well as its related definition, connotation and calculation formula. Meanwhile, by taking the Hebei Plain as an example, the article has made an evaluation of groundwater exploitation potentiality and a contrast with the results of the traditional evaluation methods on the construction of groundwater niche index system, and then verified the feasibility and rationality of this index system. It turns out that, it is truly comprehensive, scientific and rational to make groundwater niche calculation and exploitation potential analysis by using the evaluation index system. Niche theory has provided a new and fundamental attempt for the analysis and competition strategy for the groundwater exploitation potentiality evaluation.
基金financially supported by the Fundamental Research Fund of the Chinese Academy of Geological Sciences (YYFM201624)
文摘Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological wet fronts were different. The sandy loam had the fastest migration rate, the loam followed, and the clay loam was the slowest, but the law of change is the same among the three lithologies. The volumetric water content affects the change of Boltzmann parameter λ. When the volumetric water content is between 0.35-0.45 cm^3/cm^3,λ approaches stability. When the volumetric water content is less than 0.35 cm^3/cm^3, the λ value decreases rapidly with the decrease of water content. The water diffusion rate is related to the volumetric water content and particle size. The greater the moisture content is, the greater the diffusion rate will be. The larger the particle size, the larger the diffusion rate. The diffusivity of sandy loam is 10-30 times larger than that of loam and clay loam. The relationship between water content and diffusion rate is in accordance with the exponential function .
基金This work was supported by the National Natural Science Foundation of China(Grant No.40335046).
文摘Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet analysis in this article. The periodic oscillation of rainfall variation and the points of abrupt change at different time scales along the time series are dis-covered. According to the main periods, the trend of rainfall variation in the future has also been estimated. The results indicate that there are obvious periodic oscillations of 8―12 years and 4―6 years for the seasonal and annual rainfalls variation. The variation trend of the summer rainfall is in agreement with that of the annual rainfall and both of them have the main periods of 1 year and 12 years. It is estimated, based on the main period of 1 year, that the amount of rainfall will be relatively small around 2003 and abundant around 2004―2007 in the Hebei Plain.
基金National Natural Science Foundation of China,No.41101085
文摘This study firstly analyzed the shrinkage of winter wheat and the changes of crop- ping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calcu- lated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are as follows. 1) The sown areas of winter wheat in the 11 cities in the Hebei Plain all shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×10^4 ha. The shrinkage was most serious in the Bei- jing-Tianjin-Tangshan metropolitan agglomerate, with a shrinkage rate of 47.23%. 2) The precipitation fill rate of winter wheat was only 20%-30%, while those of spring maize and summer maize both exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged only from 160 mm to 210 ram. 3) The water resources conserved as a result of the winter wheat sown area shrinkage during the study period were about 15.96×10^8 m^3/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Mid-Route of the South-to-North Water Diversion Project.
基金financially supported by the National Basic Research Program of China (No. 2010CB428803)the National Natural Science Foundation of China (Nos. 41272252, 41472225)
文摘It becomes an increasing concern that groundwater quality in exploited deep confined aquifer may deteriorate due to brackish water leakage from its overlying saline aquifer in Hebei Plain. However, the monitoring data show that the TDS does not significantly change in the exploited aquifer. Some physics or chemistry processes must have taken place in aquitards during brackish leakage. The semi-permeable membrane function of clay aquitard during the process of hyperfiltration(reverse osmosis) should be one of the most important processes. To confirm and test this hyperfiltration mechanism, a series of experiments were performed in which Na Cl solutions were hydraulically forced through different clay sampled from aquitard. The solution 7 g/L in NaC l was forced through at 20 °C by a fluid pressure of 0.5 kN. The results show that hyperfiltration indeed happens in caly aquitard. Semi-permeability is quantified by the reflection coefficient σ. The mean rejection coefficients(σ) for clay samples #1, #2 and #3 were estimated to be 0.063, 0.164 and 0.040, respectively. This behavior of clay was well explained with the theory of the diffuse double layer. The hyperfiltration effect is to the great extent responsible for the chemical process in the aquitard.
基金financially supported by the National Basic Research Program of China (No. 2010CB428804)the Geological Survey Program of China Geological Survey (No. 12120113103700)
文摘Groundwater is the main water source in the Hebei Plain. Evolution of groundwater chemistry can not only provide scientific data for sustainable usage of groundwater resources, but also help us in better understanding hydrogeochemical processes in aquifers. Spatial distribution and temporal evolution were analyzed on basis of monitoring data between 1975 and 2005. Results showed that major components in groundwater had increasing trends since 1970s. Major components in shallow groundwater increased more than those in deep one. In shallow groundwater of piedmont alluvial fan-recharge zone, concentrations of Na+, Ca2+, SO42- had great increasing trends, while other major components increased by less than 30%. There were great increasing trends in Na+, Cl-, SO42- concentrations in deep groundwater of central alluvial plain-intermediate zone, while other major components increased by no more than 20%. Deep groundwater from coast plain-discharge zone and piedmont alluvial fan-recharge zone showed no significant variations in major ion concentrations. In shallow groundwater, dissolution, evaporation and human activities played a major role in the increase in major components. However, groundwater mixture resulting from deep groundwater exploitation was believed to be the major factors for the increases in major components in deep groundwater of central alluvial plain-intermediate zone.