[Objective] The aim was to explore the optimal density and nitrogen rate of no-tilling and direct sowing rapeseeds in Chengdu plain. [Methods] Effects of in- teraction between density and nitrogen rate on the growth a...[Objective] The aim was to explore the optimal density and nitrogen rate of no-tilling and direct sowing rapeseeds in Chengdu plain. [Methods] Effects of in- teraction between density and nitrogen rate on the growth and yield of direct sowing rapeseed under no-tillage condition were investigated with Chuanyou 58 as materials and a split-plot experiment adopted. [Results] In Chengdu Plain, the yields of rape- seed changed from increasing to decreasing with increase of density and nitrogen rate. Both of density and nitrogen rate had significant effects on growth and yield of rapeseed and the latter overweighed in the effect. In addition, interaction of the two had negative effects on rapeseed yield. The yield of rapeseeds achieved the highest at 3 395.25 kg/hm^2 with interaction of density at 30.00×10^4 plant/hm^2 and nitrogen rate at 180.00 kg/hm^2; the theoretical maximal yield was 3 403.41 kg/hm^2 with interaction of density at 40.80×10^4 plants/hm^2 and nitrogen rate at 198.90 kg/hm^2. [Conclusion] In Chengdu Plain, the optimal density and nitrogen rate are 30.00×10^4-45.00×10^4 plant/hm^2 and 180.00-198.90 kg/hm^2, respectively.展开更多
In this study Chengdu Red Earth （CRE） from the Chengdu Plain （CP）,Sichuan province,was analyzed for its elemental （major and trace elements） and isotopic （Sm-Nd） geochemistry and compared with Pleistocene loes...In this study Chengdu Red Earth （CRE） from the Chengdu Plain （CP）,Sichuan province,was analyzed for its elemental （major and trace elements） and isotopic （Sm-Nd） geochemistry and compared with Pleistocene loess and paleosol samples from the Chinese Loess Plateau （CLP） in Northern China.The geochemical composition of CRE is similar to north China loess,and also resembles the average UCC.This indicates that CRE,as loess deposits in Northern China,was derived from well-mixed sedimentary protoliths that have undergone numerous upper crustal recycling processes.However,obvious differences in the geochemical characteristics of CRE and the north China loess are also revealed in our results.For chemically stable elements,CRE has higher Ti,Zr,Hf and lower ΣREE,Ba contents in comparison with loess samples from the CLP.Further analysis shows that CRE has higher TiO2/Al2O3,SiO2/Al2O3,Ba/Rb and lower Ce/Yb,Eu/Yb,LaN/YbN and ΣLREE/ ΣHREE ratios.In Sm-Nd isotopic geochemistry,Sm and Nd content and the εNd（0） value in CRE are significantly higher than those in north China loess.The higher TiO2 content in CRE coincided with a high background concentration of Ti in the Sichuan Basin and the surrounding regions.The lower ΣREE and higher Sm,Nd,εNd（0） values are related to the wide distribution of basalt in the southwest Sichuan Basin.The elemental and isotopic geochemistry of CRE indicates that eolian materials in the CP predominantly come from the Sichuan Basin and the surrounding regions,which differs from loess deposits in the CLP.展开更多
On the basis of investigation and analysis of Linpan in Chengdu Plain,in view of the ongoing reconstruction engineering of residential styles in Chengdu Plain,construction mode of Linpan in Chengdu Plain at new period...On the basis of investigation and analysis of Linpan in Chengdu Plain,in view of the ongoing reconstruction engineering of residential styles in Chengdu Plain,construction mode of Linpan in Chengdu Plain at new period had been proposed and plants had been selected in accordance with the function features of different modes. The initial study result was of certain instructive significance to the protection and development of Linpan in Chengdu Plain to some extent.展开更多
The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hinde...The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.展开更多
In recent years,with the rapid development of urbanization in our country,academic circles have paid more attentions to and made fruitful achievements on the research of vernacular settlement. On this basis,this paper...In recent years,with the rapid development of urbanization in our country,academic circles have paid more attentions to and made fruitful achievements on the research of vernacular settlement. On this basis,this paper took Chengdu Plain's traditional town spatial morphology as the research object to interpret its spatial form through its composition elements and characteristics which are influenced by nature,history,culture and other factors. And then,it took Jiezi ancient town as an example to analyze the renewal of its spatial form so as to inherit the vernacular culture and promote the conservation of cultural heritage and sustainable development of traditional town in the course of constructing urban cities with Chinese characteristics.展开更多
Traditional rural homegarden agroforestry system in the Chengdu Plain of China,called“Linpan”in Chinese,integrates the ecological functions of the landscape with human production activities.Studying the driving mech...Traditional rural homegarden agroforestry system in the Chengdu Plain of China,called“Linpan”in Chinese,integrates the ecological functions of the landscape with human production activities.Studying the driving mechanisms of rural landscape changes in the Chengdu Plain is of great significance from stakeholders’perspective.Taking the Pidu Linpan Farming System(PLFS)in the suburban area of Chengdu(designated as one of China-Nationally Important Agricultural Heritage Systems in 2020)as a case,this study combined remote sensing image analysis,oral history interviews,and focus group interviews to elucidate the driving forces of landscape changes in the PLFS.The results show that tourism development,traffic accessibility,economic demand,and agricultural heritage protection measure are the main driving forces promoting the stability and maintenance of the traditional homegardens.In contrast,population ageing,land circulation,centralized residence,climate change,and living and recreational need are the forces leading to adverse changes in the traditional homegardens.In addition,these driving forces have led to the gradual abandonment of traditional agricultural activities and critical issues related to rural landscape planning and management.The current research indicates that infrastructure construction and increased traditional agricultural income are considered as the best practices of local stakeholders,promoting the development of the protected homegardens of heritage sites and tourist destinations.Finally,we put forward some suggestions to improve and maintain the traditional rural landscape:(1)establishing a benefit-sharing mechanism;(2)establishing a training system with traditional technology and culture;(3)strengthening infrastructure construction;(4)promoting the development of the agricultural industry;(5)improving the cultural quality of farmers;and(6)establishing a management system with legal effects.This research can provide a basis for the formulation of rural landscape planning and the orderly and healthy development of agricultural heritage in Chengdu Plain.展开更多
Summarizing the existing data of seismological and geological investigations and of strong and intermediate-strong earthquakes in the Sichuan basin and its adjacent areas accumulated by the seismological and petroleum...Summarizing the existing data of seismological and geological investigations and of strong and intermediate-strong earthquakes in the Sichuan basin and its adjacent areas accumulated by the seismological and petroleum organizations in Sichuan and of the results of seismic prospecting and detailed exploration in Chengdu depression during the last 20 years permitted us to study the types and distribution of hidden structures in Chengdu depression and its adjacent areas, in particular, to identify in detail the “hidden faults" in the Chenngdu-Deyang area on the one hand; The obtained data indicate that the NE-trending Xinjin fault runs northward and dies out in the south of Penzhen town of Shuangliu County. Meanwhile, we studied genetic relations of seismic activity to active faults and their corresponding movement characteristics on the other hand. Moreover, the surface faults and deep-seated faults are clearly defined and outlined, and 5 types of seismogenic faults suggested. The knowledge thus obtained enables us to delimit the focal zones for potential strong earthquakes in Chengdu depression. The study suggests that a zone of 40 km wide and more than 100 km long on sides along the Chengdu-Deyang line has a stable seismogeological background and good engineering-seismological conditions.展开更多
With Huayuan Town in Pi County as a case study,through analysis on spatial landscape layout,traditional architecture and folk culture,sustainable development approach of Linpan landscape in Chengdu Plain was discussed...With Huayuan Town in Pi County as a case study,through analysis on spatial landscape layout,traditional architecture and folk culture,sustainable development approach of Linpan landscape in Chengdu Plain was discussed,so as to conclude the main development points of Linpan landscape which contained protection of overall layout,reservation of traditional folk culture and development of traditional economy.Through protecting Linpan community landscape,its simple features were retained.Through diversified protection and utilization of architectures on Chengdu Plain,multiple protection mechanisms with participation of community residents were established,so as to preserve authenticity of Linpan landscape and ensure sustainable development of Linpan landscape.展开更多
Soil bulk density is a basic but important physic soil property related to soil porosity,soil moisture and hydraulic conductivity,which is crucial to soil quality assessment and land use management.In this study,we ev...Soil bulk density is a basic but important physic soil property related to soil porosity,soil moisture and hydraulic conductivity,which is crucial to soil quality assessment and land use management.In this study,we evaluated the spatial variability of soil bulk density in the 0–20,20–40,40–60 and 60–100 cm layers as well as its affecting factors in Southwest China’s agricultural intensive area.Results indicated the mean value of surface soil bulk density(0–20 cm)was 1.26 g cm^(–3),significantly lower than that of subsoil(20–100 cm).No statistical difference existed among the subsoil with a mean soil bulk density of 1.54 g cm^(–3).Spatially,soil bulk density played a similar spatial pattern in soil profile,whereas obvious differences were found in details.The nugget effects for soil bulk density in the 0–20 and 20–40 cm layers were 27.22 and27.02%while 12.06 and 3.46%in the 40–60 and 60–100 cm layers,respectively,gradually decreasing in the soil profile,indicating that the spatial variability of soil bulk density above 40 cm was affected by structural and random factors while dominated by structural factors under 40 cm.Soil organic matter was the controlling factor on the spatial variability of soil bulk density in each layer.Land use and elevation were another two dominated factor controlling the spatial variability of soil bulk density in the 0–20 and 40–60 cm layers,respectively.Soil genus was one of the dominated factors controlling the spatial variability of soil bulk below 40 cm.展开更多
Traditional market-towns in Chengdu Plain are blessed with rich vernacular cultural resources. In addition to summarizing characteristics of landscape image, image of downtown street and cultural symbiosis image of th...Traditional market-towns in Chengdu Plain are blessed with rich vernacular cultural resources. In addition to summarizing characteristics of landscape image, image of downtown street and cultural symbiosis image of the traditional market-town space, this paper, based on the discussion of the renewal design of the Ancient Luodai Town, analyzes the physical elements that constitute the space image, such as the street, interface, area, node and identifiability of landmark building, so as to explore how to create the space image of the traditional market-town with distinctive vernacular cultural characteristics in the construction of the vernacular human settlements.展开更多
Two red earth sections from the Chengdu Plain in Sichuan Province are dated using geomagnetic methods. The Brunhes/Matuyama (B/M) reversal boundary is recognized within the upper parts of the two sections,and the Jara...Two red earth sections from the Chengdu Plain in Sichuan Province are dated using geomagnetic methods. The Brunhes/Matuyama (B/M) reversal boundary is recognized within the upper parts of the two sections,and the Jaramillo normal subzone occurs in the middle-lower parts of the vermiculated red soil (VRS),which indicate that the parent material for the VRS deposited in the middle Quaternary. Sedimentologic and geochemical studies suggest that the Chengdu Clay and part of the parent material for the VRS are of aeolian origin. Pollen analysis indicates that the Chengdu Plain was mainly covered by needle-leaved forest with a cool to cool temperate humid climate when the parent material for the VRS deposited. The relatively cool to cool temperate climatic condition in the Chengdu Plain in the middle Quaternary,which may be caused by the uplift of the Tibetan Plateau,was a response to the geo-environmental changes of global significance.展开更多
【目的】成都平原是中华文明的重要发源地之一,深入重建该地区中—晚全新世环境演变历史,对理解长江上游史前文明发展的环境背景及探讨全球气候变化与人类社会可持续发展的关系具有重要意义。目前学界对成都平原中—晚全新世气候演变特...【目的】成都平原是中华文明的重要发源地之一,深入重建该地区中—晚全新世环境演变历史,对理解长江上游史前文明发展的环境背景及探讨全球气候变化与人类社会可持续发展的关系具有重要意义。目前学界对成都平原中—晚全新世气候演变特征及其是否响应“4.2 ka”气候突变事件仍存在争议。【方法】基于RS-1岩心的AMS 14C测年构建年代框架,采用粒度端元模型分析,结合磁化率和色度指标,重建成都平原中—晚全新世的沉积环境演变过程。【结果】粒度数据分解出5个端元组分,分别反映不同水动力条件下的沉积特征,其中EM1代表弱水动力条件下由河流远源悬浮物形成的稳定沉积;EM2和EM3反映较强水动力条件下沉积的组分,EM3对应更强的搬运动力;EM4和EM5则代表洪水期间的粗颗粒跃移沉积组分。【结论】成都平原中—晚全新世的环境演变可划分为四个阶段:4.7~4.4 cal ka B.P.期间气候湿润,干湿波动显著;4.4~4.2 cal ka B.P.气候出现轻微冷干化趋势;4.2~3.7 cal ka B.P.为气候极端不稳定期,洪水事件频发;3.7 cal ka B.P.以后气候逐渐干旱,这种“干—湿—干”的气候变化模式反映了该区域对“4.2 ka事件”的显著响应,区域水文气候的响应大约始于4.4 cal ka B.P.,并持续至约3.7 cal ka B.P.。展开更多
基金Supported by National Science and Technology Support Program(2010BAD01B08)Sichuan Finance Gene Engineering Program(2011JYGC04-013)12th Five Year Breeding Project of Crops of Sichuan Province~~
文摘[Objective] The aim was to explore the optimal density and nitrogen rate of no-tilling and direct sowing rapeseeds in Chengdu plain. [Methods] Effects of in- teraction between density and nitrogen rate on the growth and yield of direct sowing rapeseed under no-tillage condition were investigated with Chuanyou 58 as materials and a split-plot experiment adopted. [Results] In Chengdu Plain, the yields of rape- seed changed from increasing to decreasing with increase of density and nitrogen rate. Both of density and nitrogen rate had significant effects on growth and yield of rapeseed and the latter overweighed in the effect. In addition, interaction of the two had negative effects on rapeseed yield. The yield of rapeseeds achieved the highest at 3 395.25 kg/hm^2 with interaction of density at 30.00×10^4 plant/hm^2 and nitrogen rate at 180.00 kg/hm^2; the theoretical maximal yield was 3 403.41 kg/hm^2 with interaction of density at 40.80×10^4 plants/hm^2 and nitrogen rate at 198.90 kg/hm^2. [Conclusion] In Chengdu Plain, the optimal density and nitrogen rate are 30.00×10^4-45.00×10^4 plant/hm^2 and 180.00-198.90 kg/hm^2, respectively.
基金supported by the National Department Public Benefit Research Foundation of China (grant no. 201211077)the Mineral Resources Investigation and Appraisal Project of the Ministry of Land and Resources (grant nos. 41212011087118 and 1212010914041)
文摘In this study Chengdu Red Earth （CRE） from the Chengdu Plain （CP）,Sichuan province,was analyzed for its elemental （major and trace elements） and isotopic （Sm-Nd） geochemistry and compared with Pleistocene loess and paleosol samples from the Chinese Loess Plateau （CLP） in Northern China.The geochemical composition of CRE is similar to north China loess,and also resembles the average UCC.This indicates that CRE,as loess deposits in Northern China,was derived from well-mixed sedimentary protoliths that have undergone numerous upper crustal recycling processes.However,obvious differences in the geochemical characteristics of CRE and the north China loess are also revealed in our results.For chemically stable elements,CRE has higher Ti,Zr,Hf and lower ΣREE,Ba contents in comparison with loess samples from the CLP.Further analysis shows that CRE has higher TiO2/Al2O3,SiO2/Al2O3,Ba/Rb and lower Ce/Yb,Eu/Yb,LaN/YbN and ΣLREE/ ΣHREE ratios.In Sm-Nd isotopic geochemistry,Sm and Nd content and the εNd（0） value in CRE are significantly higher than those in north China loess.The higher TiO2 content in CRE coincided with a high background concentration of Ti in the Sichuan Basin and the surrounding regions.The lower ΣREE and higher Sm,Nd,εNd（0） values are related to the wide distribution of basalt in the southwest Sichuan Basin.The elemental and isotopic geochemistry of CRE indicates that eolian materials in the CP predominantly come from the Sichuan Basin and the surrounding regions,which differs from loess deposits in the CLP.
文摘On the basis of investigation and analysis of Linpan in Chengdu Plain,in view of the ongoing reconstruction engineering of residential styles in Chengdu Plain,construction mode of Linpan in Chengdu Plain at new period had been proposed and plants had been selected in accordance with the function features of different modes. The initial study result was of certain instructive significance to the protection and development of Linpan in Chengdu Plain to some extent.
基金funded by the National Key Technologies Research and Development Program of China(2006BAD02A05)the Science and Technology Project for Public (Agriculture)the Ministry of Agriculture, China (200903050-4)
文摘The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.
基金Sponsored by Southwest Jiaotong University Young Teachers 100-Talent Program Fund Project(2682014BR082)
文摘In recent years,with the rapid development of urbanization in our country,academic circles have paid more attentions to and made fruitful achievements on the research of vernacular settlement. On this basis,this paper took Chengdu Plain's traditional town spatial morphology as the research object to interpret its spatial form through its composition elements and characteristics which are influenced by nature,history,culture and other factors. And then,it took Jiezi ancient town as an example to analyze the renewal of its spatial form so as to inherit the vernacular culture and promote the conservation of cultural heritage and sustainable development of traditional town in the course of constructing urban cities with Chinese characteristics.
基金funded by the National Natural Science Foundation of China(52008278)。
文摘Traditional rural homegarden agroforestry system in the Chengdu Plain of China,called“Linpan”in Chinese,integrates the ecological functions of the landscape with human production activities.Studying the driving mechanisms of rural landscape changes in the Chengdu Plain is of great significance from stakeholders’perspective.Taking the Pidu Linpan Farming System(PLFS)in the suburban area of Chengdu(designated as one of China-Nationally Important Agricultural Heritage Systems in 2020)as a case,this study combined remote sensing image analysis,oral history interviews,and focus group interviews to elucidate the driving forces of landscape changes in the PLFS.The results show that tourism development,traffic accessibility,economic demand,and agricultural heritage protection measure are the main driving forces promoting the stability and maintenance of the traditional homegardens.In contrast,population ageing,land circulation,centralized residence,climate change,and living and recreational need are the forces leading to adverse changes in the traditional homegardens.In addition,these driving forces have led to the gradual abandonment of traditional agricultural activities and critical issues related to rural landscape planning and management.The current research indicates that infrastructure construction and increased traditional agricultural income are considered as the best practices of local stakeholders,promoting the development of the protected homegardens of heritage sites and tourist destinations.Finally,we put forward some suggestions to improve and maintain the traditional rural landscape:(1)establishing a benefit-sharing mechanism;(2)establishing a training system with traditional technology and culture;(3)strengthening infrastructure construction;(4)promoting the development of the agricultural industry;(5)improving the cultural quality of farmers;and(6)establishing a management system with legal effects.This research can provide a basis for the formulation of rural landscape planning and the orderly and healthy development of agricultural heritage in Chengdu Plain.
文摘Summarizing the existing data of seismological and geological investigations and of strong and intermediate-strong earthquakes in the Sichuan basin and its adjacent areas accumulated by the seismological and petroleum organizations in Sichuan and of the results of seismic prospecting and detailed exploration in Chengdu depression during the last 20 years permitted us to study the types and distribution of hidden structures in Chengdu depression and its adjacent areas, in particular, to identify in detail the “hidden faults" in the Chenngdu-Deyang area on the one hand; The obtained data indicate that the NE-trending Xinjin fault runs northward and dies out in the south of Penzhen town of Shuangliu County. Meanwhile, we studied genetic relations of seismic activity to active faults and their corresponding movement characteristics on the other hand. Moreover, the surface faults and deep-seated faults are clearly defined and outlined, and 5 types of seismogenic faults suggested. The knowledge thus obtained enables us to delimit the focal zones for potential strong earthquakes in Chengdu depression. The study suggests that a zone of 40 km wide and more than 100 km long on sides along the Chengdu-Deyang line has a stable seismogeological background and good engineering-seismological conditions.
文摘With Huayuan Town in Pi County as a case study,through analysis on spatial landscape layout,traditional architecture and folk culture,sustainable development approach of Linpan landscape in Chengdu Plain was discussed,so as to conclude the main development points of Linpan landscape which contained protection of overall layout,reservation of traditional folk culture and development of traditional economy.Through protecting Linpan community landscape,its simple features were retained.Through diversified protection and utilization of architectures on Chengdu Plain,multiple protection mechanisms with participation of community residents were established,so as to preserve authenticity of Linpan landscape and ensure sustainable development of Linpan landscape.
基金supported by the National Natural Science Foundation of China (4120124)the Science Fund of the Education Department of Sichuan Province, China (16ZB0048)
文摘Soil bulk density is a basic but important physic soil property related to soil porosity,soil moisture and hydraulic conductivity,which is crucial to soil quality assessment and land use management.In this study,we evaluated the spatial variability of soil bulk density in the 0–20,20–40,40–60 and 60–100 cm layers as well as its affecting factors in Southwest China’s agricultural intensive area.Results indicated the mean value of surface soil bulk density(0–20 cm)was 1.26 g cm^(–3),significantly lower than that of subsoil(20–100 cm).No statistical difference existed among the subsoil with a mean soil bulk density of 1.54 g cm^(–3).Spatially,soil bulk density played a similar spatial pattern in soil profile,whereas obvious differences were found in details.The nugget effects for soil bulk density in the 0–20 and 20–40 cm layers were 27.22 and27.02%while 12.06 and 3.46%in the 40–60 and 60–100 cm layers,respectively,gradually decreasing in the soil profile,indicating that the spatial variability of soil bulk density above 40 cm was affected by structural and random factors while dominated by structural factors under 40 cm.Soil organic matter was the controlling factor on the spatial variability of soil bulk density in each layer.Land use and elevation were another two dominated factor controlling the spatial variability of soil bulk density in the 0–20 and 40–60 cm layers,respectively.Soil genus was one of the dominated factors controlling the spatial variability of soil bulk below 40 cm.
基金Sponsored by One Hundred Young Teachers Program of Southwest Jiaotong University(2682014BR082)
文摘Traditional market-towns in Chengdu Plain are blessed with rich vernacular cultural resources. In addition to summarizing characteristics of landscape image, image of downtown street and cultural symbiosis image of the traditional market-town space, this paper, based on the discussion of the renewal design of the Ancient Luodai Town, analyzes the physical elements that constitute the space image, such as the street, interface, area, node and identifiability of landmark building, so as to explore how to create the space image of the traditional market-town with distinctive vernacular cultural characteristics in the construction of the vernacular human settlements.
基金the Geological Survey Program (Grant No. 1212010541401)the National Natural Science Foundation of China (Grant No. 40472088 and 40572169)
文摘Two red earth sections from the Chengdu Plain in Sichuan Province are dated using geomagnetic methods. The Brunhes/Matuyama (B/M) reversal boundary is recognized within the upper parts of the two sections,and the Jaramillo normal subzone occurs in the middle-lower parts of the vermiculated red soil (VRS),which indicate that the parent material for the VRS deposited in the middle Quaternary. Sedimentologic and geochemical studies suggest that the Chengdu Clay and part of the parent material for the VRS are of aeolian origin. Pollen analysis indicates that the Chengdu Plain was mainly covered by needle-leaved forest with a cool to cool temperate humid climate when the parent material for the VRS deposited. The relatively cool to cool temperate climatic condition in the Chengdu Plain in the middle Quaternary,which may be caused by the uplift of the Tibetan Plateau,was a response to the geo-environmental changes of global significance.
文摘【目的】成都平原是中华文明的重要发源地之一,深入重建该地区中—晚全新世环境演变历史,对理解长江上游史前文明发展的环境背景及探讨全球气候变化与人类社会可持续发展的关系具有重要意义。目前学界对成都平原中—晚全新世气候演变特征及其是否响应“4.2 ka”气候突变事件仍存在争议。【方法】基于RS-1岩心的AMS 14C测年构建年代框架,采用粒度端元模型分析,结合磁化率和色度指标,重建成都平原中—晚全新世的沉积环境演变过程。【结果】粒度数据分解出5个端元组分,分别反映不同水动力条件下的沉积特征,其中EM1代表弱水动力条件下由河流远源悬浮物形成的稳定沉积;EM2和EM3反映较强水动力条件下沉积的组分,EM3对应更强的搬运动力;EM4和EM5则代表洪水期间的粗颗粒跃移沉积组分。【结论】成都平原中—晚全新世的环境演变可划分为四个阶段:4.7~4.4 cal ka B.P.期间气候湿润,干湿波动显著;4.4~4.2 cal ka B.P.气候出现轻微冷干化趋势;4.2~3.7 cal ka B.P.为气候极端不稳定期,洪水事件频发;3.7 cal ka B.P.以后气候逐渐干旱,这种“干—湿—干”的气候变化模式反映了该区域对“4.2 ka事件”的显著响应,区域水文气候的响应大约始于4.4 cal ka B.P.,并持续至约3.7 cal ka B.P.。
