West Route of South-North Water Transfer Project,situated in southeastern Qinghai-Tibet Plateau,is a giant project,which will deliver 17 billion m3 of water from the main stream and tributaries upstream of the Yangtze...West Route of South-North Water Transfer Project,situated in southeastern Qinghai-Tibet Plateau,is a giant project,which will deliver 17 billion m3 of water from the main stream and tributaries upstream of the Yangtze River to the upper reaches of the Yellow River. It is to be constructed in 3 stages, of which the 1st stage project includes delivering 4 billion m3 of water by gravity from two tributaries of Yalong River and three tributaries of Dadu River. The project consists of 5 dams,7 tunnels and a channel in series,with the dam height of 63～123 m and water transfer length of 260.3 km,of which the tunnels measure 244.1 km. The special climatic,environmental and geologic conditions make the project much more complicated in construction,especially 3 tunnels with the length longer than 50 km each create challenges to the technical requirements of engineering survey,design and construction.展开更多
Surface-and subsurface-dwelling planktonic foraminifera from the upper 43 m of Hole A at the Ocean Drilling Program (ODP) Site 807,which was recovered from the western Pacific warm pool during ODP Leg 130,were analyze...Surface-and subsurface-dwelling planktonic foraminifera from the upper 43 m of Hole A at the Ocean Drilling Program (ODP) Site 807,which was recovered from the western Pacific warm pool during ODP Leg 130,were analyzed for stable oxygen and carbon isotopes.By comparing these results with data from ODP Site 851 in the eastern equatorial Pacific,this study has reconstructed the paleoceanographic changes in upper ocean waters in the equatorial Pacific since 2.5 Ma.During the period from 1.6-1.4 Ma,the oxygen isotopes of surface and subsurface waters were found to markedly change in the western and eastern equatorial Pacific,further confirming the final formation of the well-defined asymmetric east-west (E-W) pattern at that time.This feature was similar to the zonal temperature gradient (sea surface temperature is higher in the west and lower in the east) and the asymmetric upper water structure (thermocline depth is deeper in the west and shallower in the east) in the modern equatorial Pacific.The zonal gradient change of subsurface water δ18O was greater than that of surface water δ18O,indicating that the formation of the asymmetric E-W pattern in the equatorial Pacific should be much more related to the shoaled thermocline and markedly decreased subsurface water temperature in the eastern equatorial Pacific.Moreover,since ～1.6 Ma,the carbon isotopic differences between surface and subsurface waters clearly decreased in the equatorial Pacific,and their long-term eccentricity periods changed from 400 ka to ～500 ka,reflecting the reorganization of the ocean carbon reservoir.This probably resulted from the deep water reorganization in the Southern Ocean at that time and its enhanced influence on the tropical Pacific (especially subsurface water).Our study demonstrates that the tropical ocean plays an important role in global climate change.展开更多
Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region （Zichang （子长）-Yongping （水坪） ...Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region （Zichang （子长）-Yongping （水坪） Section） where the loess water erosion problem is intensely developed, the influence of water erosion on the pipeline in the loess area can be manifested as the following 3 aspects： （1） surface and gully erosion causes the base overhead and pipeline exposure; （2） underground erosion forms caves, which may cause surface subsidence and foundation failure; （3） water erosion of loess may destroy the balance of slopes and cause geological hazards like landslide, collapse and debris flow. Presently, the controlling methods are mainly concrete or grouted rubble protection. These methods are not only high in cost but also have poor effect and poor durability. This article suggests a method of controlling the loess water erosion problem with soil solidified material. Then, related tests are conducted. The results of uniaxial compression, permeability, and anti-erosion ability tests indicate that the mechanical properties and anti-erosion ability of solidified loess were improved significantly.展开更多
Topographic map evidence from the Wyoming Wind River-Sweetwater River drainage divide area is used to test a recently proposed regional geomorphology paradigm defined by massive south- and southeast-oriented continent...Topographic map evidence from the Wyoming Wind River-Sweetwater River drainage divide area is used to test a recently proposed regional geomorphology paradigm defined by massive south- and southeast-oriented continental ice sheet melt water floods that flowed across the entire Missouri River drainage basin. The new paradigm forces recognition of an ice sheet created and occupied deep “hole” and is fundamentally different from the commonly accepted paradigm in which a pre-glacial north- and northeast-oriented slope would have prevented continental ice sheet melt water from reaching or crossing the Wind River-Sweetwater River drainage divide. Divide crossings (or low points) are identified as places where water once flowed across the drainage divide. Map evidence is interpreted first from the accepted paradigm perspective and second from the new paradigm perspective to determine the simplest explanation. Both paradigm perspectives suggest south-oriented water crossed the drainage divide, although accepted paradigm interpretations do not satisfactorily explain the large number of observed divide crossings and are complicated by the need to bury the Owl Creek and Bridger Mountains to explain why the Wind River now flows in a north direction through Wind River Canyon. New paradigm interpretations explain the large number of divide crossings as diverging and converging channel evidence (as in flood-formed anastomosing channel complexes), Owl Creek and Bridger Mountain uplift to have occurred as south-oriented floodwaters carved Wind River Canyon, and a major flood flow reversal (caused by ice sheet related crustal warping and the opening up of deep “hole” space by ice sheet melting) as being responsible for the Wind River abrupt turn to the north. While this test only addresses topographic map evidence, Occam’s Razor suggests the new paradigm offers what in science should be the preferred Wind River-Sweetwater River drainage divide origin interpretations.展开更多
文摘West Route of South-North Water Transfer Project,situated in southeastern Qinghai-Tibet Plateau,is a giant project,which will deliver 17 billion m3 of water from the main stream and tributaries upstream of the Yangtze River to the upper reaches of the Yellow River. It is to be constructed in 3 stages, of which the 1st stage project includes delivering 4 billion m3 of water by gravity from two tributaries of Yalong River and three tributaries of Dadu River. The project consists of 5 dams,7 tunnels and a channel in series,with the dam height of 63～123 m and water transfer length of 260.3 km,of which the tunnels measure 244.1 km. The special climatic,environmental and geologic conditions make the project much more complicated in construction,especially 3 tunnels with the length longer than 50 km each create challenges to the technical requirements of engineering survey,design and construction.
基金supported by the National Natural Science Foundation of China (40806020)the National Basic Research Program of China (2007CB815901)+1 种基金the Doctoral Program Foundation of Institutions of Higher Education of China (200802471034)the China Ocean Mineral Resources R&D Association (DY115-01-2-3)
文摘Surface-and subsurface-dwelling planktonic foraminifera from the upper 43 m of Hole A at the Ocean Drilling Program (ODP) Site 807,which was recovered from the western Pacific warm pool during ODP Leg 130,were analyzed for stable oxygen and carbon isotopes.By comparing these results with data from ODP Site 851 in the eastern equatorial Pacific,this study has reconstructed the paleoceanographic changes in upper ocean waters in the equatorial Pacific since 2.5 Ma.During the period from 1.6-1.4 Ma,the oxygen isotopes of surface and subsurface waters were found to markedly change in the western and eastern equatorial Pacific,further confirming the final formation of the well-defined asymmetric east-west (E-W) pattern at that time.This feature was similar to the zonal temperature gradient (sea surface temperature is higher in the west and lower in the east) and the asymmetric upper water structure (thermocline depth is deeper in the west and shallower in the east) in the modern equatorial Pacific.The zonal gradient change of subsurface water δ18O was greater than that of surface water δ18O,indicating that the formation of the asymmetric E-W pattern in the equatorial Pacific should be much more related to the shoaled thermocline and markedly decreased subsurface water temperature in the eastern equatorial Pacific.Moreover,since ～1.6 Ma,the carbon isotopic differences between surface and subsurface waters clearly decreased in the equatorial Pacific,and their long-term eccentricity periods changed from 400 ka to ～500 ka,reflecting the reorganization of the ocean carbon reservoir.This probably resulted from the deep water reorganization in the Southern Ocean at that time and its enhanced influence on the tropical Pacific (especially subsurface water).Our study demonstrates that the tropical ocean plays an important role in global climate change.
基金supported by the National Natural Science Foundation of China (No. 40972185)
文摘Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region （Zichang （子长）-Yongping （水坪） Section） where the loess water erosion problem is intensely developed, the influence of water erosion on the pipeline in the loess area can be manifested as the following 3 aspects： （1） surface and gully erosion causes the base overhead and pipeline exposure; （2） underground erosion forms caves, which may cause surface subsidence and foundation failure; （3） water erosion of loess may destroy the balance of slopes and cause geological hazards like landslide, collapse and debris flow. Presently, the controlling methods are mainly concrete or grouted rubble protection. These methods are not only high in cost but also have poor effect and poor durability. This article suggests a method of controlling the loess water erosion problem with soil solidified material. Then, related tests are conducted. The results of uniaxial compression, permeability, and anti-erosion ability tests indicate that the mechanical properties and anti-erosion ability of solidified loess were improved significantly.
文摘Topographic map evidence from the Wyoming Wind River-Sweetwater River drainage divide area is used to test a recently proposed regional geomorphology paradigm defined by massive south- and southeast-oriented continental ice sheet melt water floods that flowed across the entire Missouri River drainage basin. The new paradigm forces recognition of an ice sheet created and occupied deep “hole” and is fundamentally different from the commonly accepted paradigm in which a pre-glacial north- and northeast-oriented slope would have prevented continental ice sheet melt water from reaching or crossing the Wind River-Sweetwater River drainage divide. Divide crossings (or low points) are identified as places where water once flowed across the drainage divide. Map evidence is interpreted first from the accepted paradigm perspective and second from the new paradigm perspective to determine the simplest explanation. Both paradigm perspectives suggest south-oriented water crossed the drainage divide, although accepted paradigm interpretations do not satisfactorily explain the large number of observed divide crossings and are complicated by the need to bury the Owl Creek and Bridger Mountains to explain why the Wind River now flows in a north direction through Wind River Canyon. New paradigm interpretations explain the large number of divide crossings as diverging and converging channel evidence (as in flood-formed anastomosing channel complexes), Owl Creek and Bridger Mountain uplift to have occurred as south-oriented floodwaters carved Wind River Canyon, and a major flood flow reversal (caused by ice sheet related crustal warping and the opening up of deep “hole” space by ice sheet melting) as being responsible for the Wind River abrupt turn to the north. While this test only addresses topographic map evidence, Occam’s Razor suggests the new paradigm offers what in science should be the preferred Wind River-Sweetwater River drainage divide origin interpretations.
