The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during Nov...The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.展开更多
Permian system is one of the best developed systems in Sanjiang area. In Yidun\|Zhongdian and in Zhiso\|Muli, The Lower Permian is clastics\|carbonates\|volcanics with interbeds of siliceous sediments, Whereas the Upp...Permian system is one of the best developed systems in Sanjiang area. In Yidun\|Zhongdian and in Zhiso\|Muli, The Lower Permian is clastics\|carbonates\|volcanics with interbeds of siliceous sediments, Whereas the Upper Permian is composed of lower part of basic volcanics and upper part of clastics\|carbonates with a total thickness of 1000～4000 meters .In Zhongzha (Batang)\|Jingping region, It is mainly carbonates of 217～1320 meters thick, But in Jingping proper, there occur about 5000 meters thick basalts of early late Permian . From Batang to Benzinan along the Jinshajiang river , the lower Permian is clastics\|volcanics\|carbonates formation with interbeds of siliceous sediments and spilite formation; Whereas the Upper Permian is clastics with volcanic interbeds; The total thickness being 3700 to 7100 meters. In Jiangda—Mangco (Mangkang), It is clastic\|carbonate\|volcanic formation of 1100 to 2400 meters . In Tuoba (Qamdo)—Haitong (Mankang)—Ximi (Mujiang ), It is mainly clastics\|carbonates formation , the Upper Permian being coal\|bearing clastics sequence and the total thickness being 700～2500 meters ,In Zhado—Zhasuosuo (Mangkang)—Deqing—Qinggu—Qinghong, It is clastic\|carbonate\|volcanic formation, locally with coal\|bearing clastics of Upper Permian and the total thickness of mainly carbonate formation and clastic formation with coal\|bearing clastic formation of Uppermian, is 800 to 2000 meters. In the whole area , the Permian strata were slightly metamorphosed, locally more intensively metamorphosed up to amphibolite facies. The fossils found belong to fusulinids, coral, brachiopods,ammonite,bivalve, gastropods, bryozoa,foraminifera, trilobite, algae ,porifera (sponge), and continental plant . Besides the Gondwana cold\|water type components of brachiopods found in Baoshan, the fossils belong mainly to Cathaysian biota, especially to South China type. In some places such as Mangkang, Guxue (Dewong), to South China type. In some places such as Mangkang, Guxue (Dewong), and Wachang (Muli), the resedimented Late Carboniferous fusulinid fossils can be found in the clastic limestone of Lower Permian, and the Early Permian or even Middle to Late Carboniferous fusulinid fossils found in Upper Permian classic limestone. All these suggest the resedimentation of biolimestone blocks or fragments related to fault\|volcanism .On the section of Tongba (Muli), the permian is continuous graded upwards into the Triassic, with a transitional zone of fossil.展开更多
3-D velocity structure of P wave in the upper mantle beneath southwestern China and its adjacent areas (10°N [similar to] 36°N, 70°E [similar to] 110°E) down to the depth of 400 km has been studied...3-D velocity structure of P wave in the upper mantle beneath southwestern China and its adjacent areas (10°N [similar to] 36°N, 70°E [similar to] 110°E) down to the depth of 400 km has been studied by using 80 974 P-wave first arrival times recorded at 165 stations from 7 053 events both within the studying areas, selected from the ISC bulletin and the Bulletin of China and NEIC fundamental seismic network. With a resolution of grid spacing of 2°×2°, the velocity heterogeneity on the horizontal profile is obvious though it attenuates with the depth increasing. On the vertical profiles of velocity along the latitude of 16°N and 24°N, the collision and extrusion of India plate to Eurasia plate is displayed, and a remarkable velocity difference between India plate and Eurasia plate is shown. In the vertical profile along the longitude of 90°E, the subducting of India plate northward beneath Eurasia plate (Tibet plateau) is also obvious. On the horizontal profile at the depth of 90 km, a slow velocity stripe from Myitkyina, Myanmar to Donghai, Vietnam seems to be related to Honghe fault belt. An illustration method of describing the resolution more directly and exactly has been proposed and utilized in this paper.展开更多
Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the conti...Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the continental slope of the SW Dongsha Island in northern margin of the South China Sea （SCS）. These mounds are characterized by hardened seabed, seafloor gas venting and folded structures, which implies the existence of active mud volcanoes. This work aims to confirm this speculation by seafloor sample dredging and to explore the potential of gas hydrates.展开更多
The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and...The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long time and wide scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous bearing and paleo pool bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.展开更多
西南高山地区生态系统类型丰富、地形复杂,是响应全球气候变化的重点区域,对全球气候变化具有重要的指示作用。应用生态系统模型(Carbon Exchange between Vegetation,Soil,and the Atmosphere,CEVSA)模型估算了1954—2010年西南高山地...西南高山地区生态系统类型丰富、地形复杂,是响应全球气候变化的重点区域,对全球气候变化具有重要的指示作用。应用生态系统模型(Carbon Exchange between Vegetation,Soil,and the Atmosphere,CEVSA)模型估算了1954—2010年西南高山地区净生态系统生产力(NEP)的时空变化,分析了其对气候变化的响应。结果表明:(1)1954—2010年西南高山地区NEP平均为29.7 g C.m-.2a-1,其中低海拔地区常绿针叶林和常绿阔叶林NEP较高,而高海拔地区的草地覆盖类型NEP较低。(2)西南高山地区NEP总量的变动范围为-8.36—29.4Tg C/a,平均每年吸收碳15.4Tg C;NEP年际下降趋势显著(P<0.05),平均每年减少0.187Tg C,下降显著的区域占研究地区总面积的35.2%(P<0.05),其中草地(-0.526 g C.m-.2a-2,P<0.01)和常绿针叶林(-0.691 g C.m-.2a-2,P<0.01)下降趋势极为显著。(3)年NEP总量的年际变化与年平均温度呈负相关(r=-0.454,P<0.01),与年降水量呈正相关(r=0.708,P<0.01),与温度显著负相关的区域占60.3%(P<0.05),与降水显著正相关的区域占52.1%(P<0.05),其中草地和常绿针叶林均与温度极显著负相关(r=-0.603,P<0.01;r=-0.485,P<0.01),而与降水量极显著正相关(r=0.554,P<0.01;r=0.749,P<0.01)。(4)西南高山地区是明显的碳汇区,但是由于土壤异养呼吸(HR,heterotrophic respiration)的增长速度大于净初级生产力(NPP,net primary production)的增长速度,最近20a有部分地区开始由碳汇转为碳源。展开更多
文摘The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.
文摘Permian system is one of the best developed systems in Sanjiang area. In Yidun\|Zhongdian and in Zhiso\|Muli, The Lower Permian is clastics\|carbonates\|volcanics with interbeds of siliceous sediments, Whereas the Upper Permian is composed of lower part of basic volcanics and upper part of clastics\|carbonates with a total thickness of 1000～4000 meters .In Zhongzha (Batang)\|Jingping region, It is mainly carbonates of 217～1320 meters thick, But in Jingping proper, there occur about 5000 meters thick basalts of early late Permian . From Batang to Benzinan along the Jinshajiang river , the lower Permian is clastics\|volcanics\|carbonates formation with interbeds of siliceous sediments and spilite formation; Whereas the Upper Permian is clastics with volcanic interbeds; The total thickness being 3700 to 7100 meters. In Jiangda—Mangco (Mangkang), It is clastic\|carbonate\|volcanic formation of 1100 to 2400 meters . In Tuoba (Qamdo)—Haitong (Mankang)—Ximi (Mujiang ), It is mainly clastics\|carbonates formation , the Upper Permian being coal\|bearing clastics sequence and the total thickness being 700～2500 meters ,In Zhado—Zhasuosuo (Mangkang)—Deqing—Qinggu—Qinghong, It is clastic\|carbonate\|volcanic formation, locally with coal\|bearing clastics of Upper Permian and the total thickness of mainly carbonate formation and clastic formation with coal\|bearing clastic formation of Uppermian, is 800 to 2000 meters. In the whole area , the Permian strata were slightly metamorphosed, locally more intensively metamorphosed up to amphibolite facies. The fossils found belong to fusulinids, coral, brachiopods,ammonite,bivalve, gastropods, bryozoa,foraminifera, trilobite, algae ,porifera (sponge), and continental plant . Besides the Gondwana cold\|water type components of brachiopods found in Baoshan, the fossils belong mainly to Cathaysian biota, especially to South China type. In some places such as Mangkang, Guxue (Dewong), to South China type. In some places such as Mangkang, Guxue (Dewong), and Wachang (Muli), the resedimented Late Carboniferous fusulinid fossils can be found in the clastic limestone of Lower Permian, and the Early Permian or even Middle to Late Carboniferous fusulinid fossils found in Upper Permian classic limestone. All these suggest the resedimentation of biolimestone blocks or fragments related to fault\|volcanism .On the section of Tongba (Muli), the permian is continuous graded upwards into the Triassic, with a transitional zone of fossil.
基金State Natural Science Foundation of China (49734150).
文摘3-D velocity structure of P wave in the upper mantle beneath southwestern China and its adjacent areas (10°N [similar to] 36°N, 70°E [similar to] 110°E) down to the depth of 400 km has been studied by using 80 974 P-wave first arrival times recorded at 165 stations from 7 053 events both within the studying areas, selected from the ISC bulletin and the Bulletin of China and NEIC fundamental seismic network. With a resolution of grid spacing of 2°×2°, the velocity heterogeneity on the horizontal profile is obvious though it attenuates with the depth increasing. On the vertical profiles of velocity along the latitude of 16°N and 24°N, the collision and extrusion of India plate to Eurasia plate is displayed, and a remarkable velocity difference between India plate and Eurasia plate is shown. In the vertical profile along the longitude of 90°E, the subducting of India plate northward beneath Eurasia plate (Tibet plateau) is also obvious. On the horizontal profile at the depth of 90 km, a slow velocity stripe from Myitkyina, Myanmar to Donghai, Vietnam seems to be related to Honghe fault belt. An illustration method of describing the resolution more directly and exactly has been proposed and utilized in this paper.
基金financially supported by the National Natural Science Foundation of China(grants No.41376062,91328205,41206039)Project of the Tectonic Evolution of China Sea and its adjacent areas(grant No.GZH201100205)+1 种基金Public Science and Technology Research Funds Projects of Ocean(grant No.201405032)sponsored by NSFC and Special Fund for strategic pilot technology,CAS
文摘Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the continental slope of the SW Dongsha Island in northern margin of the South China Sea （SCS）. These mounds are characterized by hardened seabed, seafloor gas venting and folded structures, which implies the existence of active mud volcanoes. This work aims to confirm this speculation by seafloor sample dredging and to explore the potential of gas hydrates.
文摘The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long time and wide scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous bearing and paleo pool bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.
文摘西南高山地区生态系统类型丰富、地形复杂,是响应全球气候变化的重点区域,对全球气候变化具有重要的指示作用。应用生态系统模型(Carbon Exchange between Vegetation,Soil,and the Atmosphere,CEVSA)模型估算了1954—2010年西南高山地区净生态系统生产力(NEP)的时空变化,分析了其对气候变化的响应。结果表明:(1)1954—2010年西南高山地区NEP平均为29.7 g C.m-.2a-1,其中低海拔地区常绿针叶林和常绿阔叶林NEP较高,而高海拔地区的草地覆盖类型NEP较低。(2)西南高山地区NEP总量的变动范围为-8.36—29.4Tg C/a,平均每年吸收碳15.4Tg C;NEP年际下降趋势显著(P<0.05),平均每年减少0.187Tg C,下降显著的区域占研究地区总面积的35.2%(P<0.05),其中草地(-0.526 g C.m-.2a-2,P<0.01)和常绿针叶林(-0.691 g C.m-.2a-2,P<0.01)下降趋势极为显著。(3)年NEP总量的年际变化与年平均温度呈负相关(r=-0.454,P<0.01),与年降水量呈正相关(r=0.708,P<0.01),与温度显著负相关的区域占60.3%(P<0.05),与降水显著正相关的区域占52.1%(P<0.05),其中草地和常绿针叶林均与温度极显著负相关(r=-0.603,P<0.01;r=-0.485,P<0.01),而与降水量极显著正相关(r=0.554,P<0.01;r=0.749,P<0.01)。(4)西南高山地区是明显的碳汇区,但是由于土壤异养呼吸(HR,heterotrophic respiration)的增长速度大于净初级生产力(NPP,net primary production)的增长速度,最近20a有部分地区开始由碳汇转为碳源。
