Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocen...Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.展开更多
Based on global monthly average data set of sea surface temperature (SST) during 1950 - 1992 and global monthly average 500 hPa height during 1930- 1997 offered by NCARINCEP, the feature of SST anomaly in the Atlantic...Based on global monthly average data set of sea surface temperature (SST) during 1950 - 1992 and global monthly average 500 hPa height during 1930- 1997 offered by NCARINCEP, the feature of SST anomaly in the Atlantic and its relation with summer precipitation over the Northeast China are analyzed. The results show that, the second eigenvector of the SST’s empirical orthogonal expanssion in winter season over the North Atlantic suggests that dist-ibution of SST anomaly has unusual meridional difference; The location of its center is basically identical to center of significant correlation region be- tween summer precipitation over the Northeast China and winter SST in the Atlantic. When winter SST in the North Atlantic is hot in south and cold in north, the blocking situation is stronger in the middle- high latitude. Correspondingly, the blocking high pressure in the northern North Pacific is also getting stronger, the westerlies circulation index in East Asia in next summer would be lower,as a result,more precipitation in the summer would be experienced over Northeast China and vice versa.展开更多
North Carnarvon盆地三叠系Mungaroo组发育典型的海陆过渡相浅水三角洲,三角洲平原亚相分布广,薄煤层广泛发育。通过岩心、薄片的观察鉴定以及测井资料、扫描电镜、黏土矿物等的分析得到三叠系储层Mungaroo组砂岩类型主要为石英砂岩和...North Carnarvon盆地三叠系Mungaroo组发育典型的海陆过渡相浅水三角洲,三角洲平原亚相分布广,薄煤层广泛发育。通过岩心、薄片的观察鉴定以及测井资料、扫描电镜、黏土矿物等的分析得到三叠系储层Mungaroo组砂岩类型主要为石英砂岩和长石石英砂岩,具有结构成熟度低、成分成熟度高的特点,不同相带与构造单元砂岩物性差异较大。菱铁矿、高岭石、石英加大边与海绿石是控制Mungaroo组储层物性的典型成岩矿物类型,体现了海陆过渡相砂岩的成岩特点。近端三角洲平原亚相砂岩长石早期溶蚀生成大量土状高岭石与伊利石,且菱铁矿含量较高,充填大量原生粒间孔隙;而远端三角洲平原亚相保留了大量原生粒间孔及长石溶解形成的次生孔,储层物性较好;三角洲前缘亚相砂岩钙质及海绿石胶结物普遍发育,储层物性较差。Dampier坳陷和Barrow坳陷区埋深大,加上砂岩石英颗粒含量高,石英次生加大强烈,碎屑颗粒以线接触—缝合线接触为主;而在紧邻的Exmouth低隆起和Rankin断隆带等低隆起区由于上覆地层厚度较薄,砂岩压实程度较低,普遍发育优质储层。展开更多
Prior to the collision and accretion of the Kohistan arc terrane during the late Cretaceous and the Indian plate after the early Eocene, the southern margin of Asia along the Hindu Kush, Karakoram and Lhasa block terr...Prior to the collision and accretion of the Kohistan arc terrane during the late Cretaceous and the Indian plate after the early Eocene, the southern margin of Asia along the Hindu Kush, Karakoram and Lhasa block terranes was an active Andean\|type continental margin. In south Tibet this margin was dominated by the calc\|alkaline Ladakh—Gangdese granite batholith, associated andesitic volcanic rocks and continental red\|beds. In contrast, the southern Karakoram exposes deep crustal metamorphic rocks and crustal melt leucogranites. New U\|Pb age dating from the Hunza valley and Baltoro glacier region has revealed four spatially and temporally distinct metamorphic episodes. M1 sillimanite grade metamorphism in Hunza was a late Cretaceous event, probably caused by the accretion of the Kohistan arc to Asia. M2 was the major kyanite and sillimanite grade event during late Eocene—Oligocene crustal thickening and shortening, following India\|Asia collision. Numerous melting events resulted in the formation of crustal melt granites throughout the last 50Ma with multiple generations of dykes and very large scale crustal melting along the Baltoro monzogranite\|leucogranite ba tholith during the late Oligocene—early Miocene. M3 metamorphism was a high\| T , low\| p contact thermal metamorphism around the Baltoro granite. In Hunza, younger staurolite grade metamorphism has been dated by U\|Pb monazites at 16Ma, with the Sumayar leucogranite intruded at 9 5Ma cross\|cutting the metamorphic isograds. In the Baltoro region the youngest metamorphism, M4, is the sillimanite grade Dassu gneiss core complex dated by U\|Pb on monazites as late Miocene—Pliocene (5 4±0 25)Ma with Precambrian protolith zircon cores (1855±11)Ma. Numerous gem\|bearing pegmatite dykes cross\|cut these rocks and are thought to have been intruded within the last 2～3Ma. Structural mapping, combined with U\|Pb geochronology shows that major metamorphic events can be both long\|lasting (up to 20Ma) and very restrictive, both in time and space.展开更多
There were more expounding to north—west (west) trend fault and north\|east trend fault within Qiangtang Basin, North Part of Tibet, in the past literature. With increasing of geophysical exploration data, nearly eas...There were more expounding to north—west (west) trend fault and north\|east trend fault within Qiangtang Basin, North Part of Tibet, in the past literature. With increasing of geophysical exploration data, nearly east\|west trend structure began to be taken note to. Since the year of 1995, by a synthetic study to geophysical and geological data, that south\|north trend faulted structures are well developed. These structures should be paid much more attention to, because they have important theoretical meaning and practical significance.1 Spreading of south\|north faulted structure belt According to different geological and geophysical data, the six larger scale nearly south\|north faulted structure belt could be distinguished within the scope of east longitude 84°～96° and near Qiangtang Basin. The actual location of the six belts are nearly located in the west of the six meridian of east longitude 85°,87°,89°,91°,93°,95° or located near these meridian. The six south\|north faulted structure belts spread in the same interval with near 2° longitude interval. The more clear and much more significance of south\|north trend faulted structure belts are the two S—N trend faulted structure belts of east longitude 87° and 89°. There are S—N trend faulted structure belts in the west of east longitude 83°,81°, or near the longitudes. The structure belts spreading features,manifestation,geological function and its importance, and inter texture and structure are not exactly so same. The structure belts all different degree caused different region of geological structure or gravity field and magnetic field. There is different scale near S—N trend faulted structure belt between the belts.展开更多
The Altun and North Qaidam Mountains at the northern margin of Qinghai\|Tibet plateau are separated by the Altyn Tagh sinistral strike\|slip fault, which is one of the largest strike\|slip fault systems in the world a...The Altun and North Qaidam Mountains at the northern margin of Qinghai\|Tibet plateau are separated by the Altyn Tagh sinistral strike\|slip fault, which is one of the largest strike\|slip fault systems in the world and was considered as the key element in the escape tectonics model for Euraisa\|India continent\|continent collision.Recently,the eclogites within quratzifeldspathic gneisses or pelitic gneisses characterized by amphibolite\|facies paragenesis were discovered in the Altun and the North Qaidam Mountains(Fig.1). They occur as lens or boundins within the Altun Group and Dakendaban Group respectively which previously were considered as metamorphic basement of Tarim block and Qaidam block. Our studies indicate that the eclogites outcrop in both the Altun and North Qaidam Mountains show similar occurrences, associated country rocks, rock and mineral assemblages, p\|T\% estimates, geochemistryand protolith feature and ages of peak metamorphism (see table) . The garnet\|omphacite\|phengite geothermobarometer gave equilibrium condition of \%p\%=2 8～3 0GPa and t =820～850℃ for the Altun eclogite and p =2 8GPa and \%t\%=730℃ for North Qaidam eclogite respectively(Fig..2). These p\|T conditions are in the coesite stability field. Moreover, Po lycrystalline quartz pseudomorphs after coesite have been identified in the Dulan area, North Qaidam Mountains (Song et al, in review). Therefore, these features suggest that both eclogites of Altun and North Qaidam Mountains probably are a same HP\|UHP metamorphic belt formed from the same of Early Paleozoic age deep subduction and collision, and subsequently displaced by the Altyn Tagh fault.The case is similar to the Dabie\|Sulu HP\|UHP metamorphic zone which was truncated by the Tanlu sinistral strike\|slip fault and splitted it into two distincts, the Dabie region and Sulu region. These correlations support an about 350～400km displacement of the Altyn Tagh sinistral strike\|slip fault (Fig.1).展开更多
Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumatio...Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumation (Copeland 1990, Najman 1997, White 1999). However such studies require large numbers of analyses, and Ar/Ar total\|fusion of white mica grains is a very rapid and cost\|effective technique.Such analyses, however, do result in the sacrifice of internal consistency checks inherent in, for example, Ar/Ar step\|heating analysis.展开更多
Qilian orogenic belt is a typical orogenic belt formed by polycyclic collisions between the North China plate and Qaidam microplate. Qilian ocean originated from the rift of the late Proterozoic Rodinia continent(Pang...Qilian orogenic belt is a typical orogenic belt formed by polycyclic collisions between the North China plate and Qaidam microplate. Qilian ocean originated from the rift of the late Proterozoic Rodinia continent(Pangea\|850), evolved through rift basin and became an archipelagic ocean in the Caledonian stage. The Lower Proterozoic strata in Qilian area are mid\|high\|rank metamorphic rocks that constitute the metamorphic basement of the area. The “Huangyuan Movement" (in South Qilian and Central Qilian) and "Alashan Movement" (in North Qilian) in the latest Late Proterozoic formed a regional unconformity. The middle Proterozoic in the area are mudstones and carbonate rocks with stromatolites and ooids. The Qingbaikou System of the upper Proterozoic in the North Qilian and Corridor region is also mudstone and carbonate rock with stromatolites. The Qingbaikou System in Central Qilian is sandstones and mudstones. There are alkaline and tholeiite in the Sinian System in North Qilian and Corridor. The contact between Qingbaikou System and Sinian System is a regional unconformity (Quanji Movement). Qilian ocean began to rift away in Caledonian tectonic stage on the Pre\|Sinian basement.展开更多
The main canal of the Middle Route Project of South-to-North Water Transfer totals more than 1 240 km in length. In Henan Province and Hebei Province, there will be a section of more than 120 km passing through an exp...The main canal of the Middle Route Project of South-to-North Water Transfer totals more than 1 240 km in length. In Henan Province and Hebei Province, there will be a section of more than 120 km passing through an expansive soils area. Expansive soils is a special kind of tenacious clay, which swells when meeting with water and shrinks when losing water. With complicated mechanical properties, it changes with the variation of water content. As a result, expansive soils become the key object of study on unsaturated soils mechanics for the project. From the status of study on unsaturated soils at home and abroad, this paper covers an analysis on stability analysis method of expansive soils slope, determination of expansive soils strength, rational design of canal slope ratio and support, and forecast of landslide for the Middle Route Project of South-to-North Water Transfer.展开更多
Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuring...Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuringiensis （Bt） cotton. We aimed to investigate the variation in resistance of transgenic Bt cotton varieties to cotton bollworm in North China. Methods： Populations of cotton bollworm were monitored from 2008 to 2015 in environments where Bt cotton was planted adjacent to other non Bt crops. The study included 197 Bt cotton varieties planted in 42 counties/locations in three provinces （Hebei, Shandong and Henan） of North China, which were evaluated through field investigations, bioassays, and enzyme linked immunosorbent assays （ELISA）. Results： The average number of cotton bollworms never exceeded the action threshold （10 larvae per 100 cotton plants）, however, their number reached 19.55 per 100 cotton plants in 2011. The ratios of damaged plants to total Bt cotton stem tips, buds, and bolls was low except in 2010, when the ratios reached 1.82%, 2.09%, and 10.63%, respectively. The results of bioassay showed that the corrected mortality were higher at the second generation cotton bollworm stage than the third and fourth germination stages. Totally, Bt protein content declined sharply at the seedling stage from 2008 to 2015. Conclusions： This study indicated that almost all Bt cotton varieties were capable to effectively control the populations of cotton bollworm in North China.展开更多
A stratigraphic and depositional filling modal of Triassic—Jurassic North Tarim foreland basin system is erected, through synthetic analysis of geological setting, depositional provenance, sequence stratigraphy, and ...A stratigraphic and depositional filling modal of Triassic—Jurassic North Tarim foreland basin system is erected, through synthetic analysis of geological setting, depositional provenance, sequence stratigraphy, and quantitative tectonic stratigraphy. The result suggests that the major factors controlling formation and evolution of the system are oblique collision and convergence of different plates, and favorite hydrocarbon plays is predicted.The geological setting analysis emphasizes the historical succession of the foreland basin system formation and evolution. The tectonic setting analysis sketchy outlines formation of the system and tectonic setting of its successive evolution. The sedimentary geology analysis reveals the uplift and subsidence of the basin basement a seesaw style movement.展开更多
As a characteristic sedimentary type,molartooth carbonatites veins(MCV) can be found in almost all the Neoproterozoic carbonatite strata in the North Anhui and Jiangsu Provinces.But their forming mechanism is still an...As a characteristic sedimentary type,molartooth carbonatites veins(MCV) can be found in almost all the Neoproterozoic carbonatite strata in the North Anhui and Jiangsu Provinces.But their forming mechanism is still an enigma,and more than four incompatible forming hypotheses have been put forward according to the structures,mineral components and elements of the MCV.Though all the MCV with the similar shape展开更多
文摘Suid is one of the most common taxa among the Pleistocene mammalian fauna in China.However,its phylogenetic taxonomy and evolution are far from clear.The newly recovered suid fossil materials from the Early Pleistocene Shanshenmiaozui site in Nihewan Basin in North China provide new insight into the evolution of its kind in North China.The new materials include partial skulls and mandibles of males,and most of their teeth were preserved in situ.The specimens can be referred to the species Sus lydekkeri,which is the only species of Sus found in North China from the Early Pleistocene.The fossils of the once reported Pleistocene species“Potamochoerus chinhsienensis”should also be provisionally included in the species S.lydekkeri according to its form and size,which at least now excludes it from Potamochoerus.The species S.lydekkeri is very close to the extant species S.scrofa,and even was combined into the latter as a chronological subspecies by some authors,while its larger size,prominent preorbital fossa,backwardly positioned infraorbital foramen,frequently appearing verrucosic type(at least the intermediate type of the male lower canine),and simple crown structures support its validness as an independent species.The Early Pleistocene forms are characterized by a larger size,lower L/W ratio of cheekteeth,both upper and lower M3s having no more than three lobes,and the male lower canine is exclusively of a verrucosic type.Suid fossils are a very good indicator of paleoenvironments and paleoclimate.Both the northern and the southern faunas in China contain suid fossils throughout the Pleistocene Epoch,while the southern fauna has prominently more diversified taxa and more abundant fossil collections;whether that is caused by different origins or by environmental modifications is still not clear.
文摘Based on global monthly average data set of sea surface temperature (SST) during 1950 - 1992 and global monthly average 500 hPa height during 1930- 1997 offered by NCARINCEP, the feature of SST anomaly in the Atlantic and its relation with summer precipitation over the Northeast China are analyzed. The results show that, the second eigenvector of the SST’s empirical orthogonal expanssion in winter season over the North Atlantic suggests that dist-ibution of SST anomaly has unusual meridional difference; The location of its center is basically identical to center of significant correlation region be- tween summer precipitation over the Northeast China and winter SST in the Atlantic. When winter SST in the North Atlantic is hot in south and cold in north, the blocking situation is stronger in the middle- high latitude. Correspondingly, the blocking high pressure in the northern North Pacific is also getting stronger, the westerlies circulation index in East Asia in next summer would be lower,as a result,more precipitation in the summer would be experienced over Northeast China and vice versa.
文摘Prior to the collision and accretion of the Kohistan arc terrane during the late Cretaceous and the Indian plate after the early Eocene, the southern margin of Asia along the Hindu Kush, Karakoram and Lhasa block terranes was an active Andean\|type continental margin. In south Tibet this margin was dominated by the calc\|alkaline Ladakh—Gangdese granite batholith, associated andesitic volcanic rocks and continental red\|beds. In contrast, the southern Karakoram exposes deep crustal metamorphic rocks and crustal melt leucogranites. New U\|Pb age dating from the Hunza valley and Baltoro glacier region has revealed four spatially and temporally distinct metamorphic episodes. M1 sillimanite grade metamorphism in Hunza was a late Cretaceous event, probably caused by the accretion of the Kohistan arc to Asia. M2 was the major kyanite and sillimanite grade event during late Eocene—Oligocene crustal thickening and shortening, following India\|Asia collision. Numerous melting events resulted in the formation of crustal melt granites throughout the last 50Ma with multiple generations of dykes and very large scale crustal melting along the Baltoro monzogranite\|leucogranite ba tholith during the late Oligocene—early Miocene. M3 metamorphism was a high\| T , low\| p contact thermal metamorphism around the Baltoro granite. In Hunza, younger staurolite grade metamorphism has been dated by U\|Pb monazites at 16Ma, with the Sumayar leucogranite intruded at 9 5Ma cross\|cutting the metamorphic isograds. In the Baltoro region the youngest metamorphism, M4, is the sillimanite grade Dassu gneiss core complex dated by U\|Pb on monazites as late Miocene—Pliocene (5 4±0 25)Ma with Precambrian protolith zircon cores (1855±11)Ma. Numerous gem\|bearing pegmatite dykes cross\|cut these rocks and are thought to have been intruded within the last 2～3Ma. Structural mapping, combined with U\|Pb geochronology shows that major metamorphic events can be both long\|lasting (up to 20Ma) and very restrictive, both in time and space.
文摘There were more expounding to north—west (west) trend fault and north\|east trend fault within Qiangtang Basin, North Part of Tibet, in the past literature. With increasing of geophysical exploration data, nearly east\|west trend structure began to be taken note to. Since the year of 1995, by a synthetic study to geophysical and geological data, that south\|north trend faulted structures are well developed. These structures should be paid much more attention to, because they have important theoretical meaning and practical significance.1 Spreading of south\|north faulted structure belt According to different geological and geophysical data, the six larger scale nearly south\|north faulted structure belt could be distinguished within the scope of east longitude 84°～96° and near Qiangtang Basin. The actual location of the six belts are nearly located in the west of the six meridian of east longitude 85°,87°,89°,91°,93°,95° or located near these meridian. The six south\|north faulted structure belts spread in the same interval with near 2° longitude interval. The more clear and much more significance of south\|north trend faulted structure belts are the two S—N trend faulted structure belts of east longitude 87° and 89°. There are S—N trend faulted structure belts in the west of east longitude 83°,81°, or near the longitudes. The structure belts spreading features,manifestation,geological function and its importance, and inter texture and structure are not exactly so same. The structure belts all different degree caused different region of geological structure or gravity field and magnetic field. There is different scale near S—N trend faulted structure belt between the belts.
文摘The Altun and North Qaidam Mountains at the northern margin of Qinghai\|Tibet plateau are separated by the Altyn Tagh sinistral strike\|slip fault, which is one of the largest strike\|slip fault systems in the world and was considered as the key element in the escape tectonics model for Euraisa\|India continent\|continent collision.Recently,the eclogites within quratzifeldspathic gneisses or pelitic gneisses characterized by amphibolite\|facies paragenesis were discovered in the Altun and the North Qaidam Mountains(Fig.1). They occur as lens or boundins within the Altun Group and Dakendaban Group respectively which previously were considered as metamorphic basement of Tarim block and Qaidam block. Our studies indicate that the eclogites outcrop in both the Altun and North Qaidam Mountains show similar occurrences, associated country rocks, rock and mineral assemblages, p\|T\% estimates, geochemistryand protolith feature and ages of peak metamorphism (see table) . The garnet\|omphacite\|phengite geothermobarometer gave equilibrium condition of \%p\%=2 8～3 0GPa and t =820～850℃ for the Altun eclogite and p =2 8GPa and \%t\%=730℃ for North Qaidam eclogite respectively(Fig..2). These p\|T conditions are in the coesite stability field. Moreover, Po lycrystalline quartz pseudomorphs after coesite have been identified in the Dulan area, North Qaidam Mountains (Song et al, in review). Therefore, these features suggest that both eclogites of Altun and North Qaidam Mountains probably are a same HP\|UHP metamorphic belt formed from the same of Early Paleozoic age deep subduction and collision, and subsequently displaced by the Altyn Tagh fault.The case is similar to the Dabie\|Sulu HP\|UHP metamorphic zone which was truncated by the Tanlu sinistral strike\|slip fault and splitted it into two distincts, the Dabie region and Sulu region. These correlations support an about 350～400km displacement of the Altyn Tagh sinistral strike\|slip fault (Fig.1).
文摘Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumation (Copeland 1990, Najman 1997, White 1999). However such studies require large numbers of analyses, and Ar/Ar total\|fusion of white mica grains is a very rapid and cost\|effective technique.Such analyses, however, do result in the sacrifice of internal consistency checks inherent in, for example, Ar/Ar step\|heating analysis.
文摘Qilian orogenic belt is a typical orogenic belt formed by polycyclic collisions between the North China plate and Qaidam microplate. Qilian ocean originated from the rift of the late Proterozoic Rodinia continent(Pangea\|850), evolved through rift basin and became an archipelagic ocean in the Caledonian stage. The Lower Proterozoic strata in Qilian area are mid\|high\|rank metamorphic rocks that constitute the metamorphic basement of the area. The “Huangyuan Movement" (in South Qilian and Central Qilian) and "Alashan Movement" (in North Qilian) in the latest Late Proterozoic formed a regional unconformity. The middle Proterozoic in the area are mudstones and carbonate rocks with stromatolites and ooids. The Qingbaikou System of the upper Proterozoic in the North Qilian and Corridor region is also mudstone and carbonate rock with stromatolites. The Qingbaikou System in Central Qilian is sandstones and mudstones. There are alkaline and tholeiite in the Sinian System in North Qilian and Corridor. The contact between Qingbaikou System and Sinian System is a regional unconformity (Quanji Movement). Qilian ocean began to rift away in Caledonian tectonic stage on the Pre\|Sinian basement.
文摘The main canal of the Middle Route Project of South-to-North Water Transfer totals more than 1 240 km in length. In Henan Province and Hebei Province, there will be a section of more than 120 km passing through an expansive soils area. Expansive soils is a special kind of tenacious clay, which swells when meeting with water and shrinks when losing water. With complicated mechanical properties, it changes with the variation of water content. As a result, expansive soils become the key object of study on unsaturated soils mechanics for the project. From the status of study on unsaturated soils at home and abroad, this paper covers an analysis on stability analysis method of expansive soils slope, determination of expansive soils strength, rational design of canal slope ratio and support, and forecast of landslide for the Middle Route Project of South-to-North Water Transfer.
基金supported by the project of China Agriculture Research System(CARS-15-20)
文摘Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuringiensis （Bt） cotton. We aimed to investigate the variation in resistance of transgenic Bt cotton varieties to cotton bollworm in North China. Methods： Populations of cotton bollworm were monitored from 2008 to 2015 in environments where Bt cotton was planted adjacent to other non Bt crops. The study included 197 Bt cotton varieties planted in 42 counties/locations in three provinces （Hebei, Shandong and Henan） of North China, which were evaluated through field investigations, bioassays, and enzyme linked immunosorbent assays （ELISA）. Results： The average number of cotton bollworms never exceeded the action threshold （10 larvae per 100 cotton plants）, however, their number reached 19.55 per 100 cotton plants in 2011. The ratios of damaged plants to total Bt cotton stem tips, buds, and bolls was low except in 2010, when the ratios reached 1.82%, 2.09%, and 10.63%, respectively. The results of bioassay showed that the corrected mortality were higher at the second generation cotton bollworm stage than the third and fourth germination stages. Totally, Bt protein content declined sharply at the seedling stage from 2008 to 2015. Conclusions： This study indicated that almost all Bt cotton varieties were capable to effectively control the populations of cotton bollworm in North China.
文摘A stratigraphic and depositional filling modal of Triassic—Jurassic North Tarim foreland basin system is erected, through synthetic analysis of geological setting, depositional provenance, sequence stratigraphy, and quantitative tectonic stratigraphy. The result suggests that the major factors controlling formation and evolution of the system are oblique collision and convergence of different plates, and favorite hydrocarbon plays is predicted.The geological setting analysis emphasizes the historical succession of the foreland basin system formation and evolution. The tectonic setting analysis sketchy outlines formation of the system and tectonic setting of its successive evolution. The sedimentary geology analysis reveals the uplift and subsidence of the basin basement a seesaw style movement.
文摘As a characteristic sedimentary type,molartooth carbonatites veins(MCV) can be found in almost all the Neoproterozoic carbonatite strata in the North Anhui and Jiangsu Provinces.But their forming mechanism is still an enigma,and more than four incompatible forming hypotheses have been put forward according to the structures,mineral components and elements of the MCV.Though all the MCV with the similar shape
