The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇...The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.展开更多
Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure F...Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure Formations (Wan, 1985; Hao and Wan, 1985; Xu, Wan, et al. 1990). The K/T boundary in Gamba was studied by Wan Xiaoqiao (1988). This paper deals with the boundary in the Tingri region. Willems (1993) discussed the Cretaceous to Tertiary sequence in the Tingri region. In his work, the Upper Cretaceous to Lower Tertiary passage beds involved the Zongshan, Zhepure Shanpo, Jidula and Zhepure Shan Formations. The lithologies in the Tingri and Gamba regions are generally comparable, and we describe the boundary sequence in the Tingri region as follows:1\ Zongshan Formation (Campanian—Middle Maastrichtian) Hao and Wan (1985) first described this formation in Tingri. It consists of limestones equivalent to the strata in Gamba. The nomination of the Zongshan formation has been used in both regions. The Formation in Gamba ranges from Campanian to Late Maastrichtian age. In Tingri, however, the upper beds were referred to the Zhepure Shanpo Formation because they are clastic sediments (Willems, 1993). Planktonic foraminifera are abundant, such as Globotruncana spp. and Omphalocyclus sp.展开更多
The Tertiary basins are distributed in the eastern margin of the Tibetan Plateau along the large\|scale arc\|shaped strike\|slip belt of the Qiangtang—Hengduan Shan—Jinshajiang—Red River belt. Most of basins were c...The Tertiary basins are distributed in the eastern margin of the Tibetan Plateau along the large\|scale arc\|shaped strike\|slip belt of the Qiangtang—Hengduan Shan—Jinshajiang—Red River belt. Most of basins were controlled by regional northwest\| and south\|north treading faults, and a few basins were constrained by northwest\| or north\|north\|east\|treading local faults.The detailed field mapping and sedimentologic observations for 6 typical Tertiary basins in eastern Tibet show that their types include depressive basins, rifting basins, pull\|apart and extensional basins related to strike\|slip faulting, and erosion\|residual basins. Recently, most of them are controlled by compression\| or thrust\|related margin faults in single side or double laterals of these basins. Not\|well\|developed strata in the Tertiary basins were deformed to form various tight folds and thrusts. High\|K magma intruded widely into the basins. The tectono\|sedimentary evolution of the Tertiary basins appears tempo\|spatially inhomogeneous. The preliminary model to interpret the Tertiary basin evolution is described as below.展开更多
The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basi...The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basin above 2300m ASL.The basin has deposited different kinds of sediments with 1600m in depth. The early Tertiary strata were first named as Lijiang formation in 1961, and later named as Hongyanzi formation. The later Tertiary strata, the lignite\|bearing strata, were once named as Xigeda formation. Li Yougheng(1978) found some mammal fossils in the strata, so they named it Yanyuan formation. The Hongyanzi Formation which thickness is 1022m can be divided into five members according to the lithologic characters. The first one is mainly made of purplish\|red coarse conglomerates. The composition of gravel mainly consists of limestone and purplish\|red sandstone and marl. The second one consists of sandstone interbedded with conglomerate. The member has three cyclic sequences from conglomerate to sandstone. The composition of gravel of this member is mainly limestone. From bottom to top the degree of sorting and roundness tends to be well. In sandstones or sand lenticules the oblique bedding and trough cross\|bedding can be seen. The third one is the member of sandstone and mudstone. The sandstone is light purple while the mudstone is purplish red. Ripple marks can be seen in the sandstone. The forth one consists of conglomerate interbedded with mudstone, The conglomerate and the sandstone assume three cyclic sequences. The composition of the gravel is chiefly limestone. The fifth one is a member of light purple massive conglomerate. The composition of the gravel is limestone. The imbricate structure can be seen in the conglomerate. The strata belong to later Eocene epoch in accordance with the fossils of mammals, plants and ostracoda in it.展开更多
The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was inv...The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was investigated. The results show that the maximum recoveries of kaolinite for DEN, DPN and DRN are 93%, 88% and 84%, respectively, but that of DBN is very low. On the basis of zeta potential and FT-IR spectra, the ionization of surface hydroxyl and isomorphic exchange of surface ions account for the charging mechanisms of kaolinite surface. The adsorption mechanism of tertiary amines on kaolinite surface is mainly electrostatic. The isoelectric point （IEP） of kaolinite increases from 3.4 to some more positive points after the interaction of kaolinite with the four tertiary amines. The FT-IR spectra of kaolinite change with the presence of some new sharp shapes belonging to the tertiary amines. The inductive electronic effects and space-steric effects of -CH3, -C2H5, -C3H7 and -C7H7 bonding to N atom result in different collecting power of the four tertiary amines.展开更多
Eocene Fenghuoshan Group and lower Oligocene Yaxicuo Group are represented by mainly fluvial, lacustrine and fan\|deltaic redbeds cropping out in Hoh Xil basin, the largest redbed basin in northern Tibet plateau. Lith...Eocene Fenghuoshan Group and lower Oligocene Yaxicuo Group are represented by mainly fluvial, lacustrine and fan\|deltaic redbeds cropping out in Hoh Xil basin, the largest redbed basin in northern Tibet plateau. Lithic sandstone, lithic quartzose sandstone, conglomerate, as well as siltstone, consist of the major rock composition of the redbeds. The petrography of sandstone and conglomerate reveals the relationship between regional tectonic uplift events and the provenance of lower Tertiary redbeds.The outcrop rock data show that the detritus were derived from sedimentary rocks, volcanic rocks, and metamorphic rocks. Phyllite and quartzite rock fragments are most common in the metamorphic rock fragments .The sedimentary rock fragments are composed of chert, limestone, siltstone, and mudstone fragments. But volcanic rock fragments are minor and occasionally occur. In Hantaishan area, the northwestern part of Hoh Xil basin, clastic composition of sandstones and conglomerates testify to mainly southward and northeastward provenances. The metamorphic rock fragments, which are more common than volcanic and sedimentary rock fragments, can be directly correlated with metamorphic rock of Triassic metasedimentary Bayankara Group around the basin. In Fenghuoshan area, the southwestern part of the basin, there are less metamorphic rock fragment composition and more limestone fragments than in Hantaishan area.The limestone fragments were obviously derived from Carboniferous—Permian or Jurassic limestone beds. These limestone strata can not be found in the Bayankara block mass at which Hoh Xil basin locates, thus it is deduced that the limestone detritus were derived from the south, that is, Qiangtang blockmass.展开更多
We focus on early Cenozoic uplift, erosion and growth of northern Tibet plateau by reconstructing paleo\|drainage pattern in the Hoh Xil basin. Stratigraphical infilling sequences and lithic type orogenic basins are d...We focus on early Cenozoic uplift, erosion and growth of northern Tibet plateau by reconstructing paleo\|drainage pattern in the Hoh Xil basin. Stratigraphical infilling sequences and lithic type orogenic basins are determined largely by contemporaneous tectonic activity. It is therefore reasonable to infer that paleoflow variability record give useful information about regional tectonic events. We now report paleocurrent data from outcrop measurement of 4 expedition profiles across the basin during 1997—1998.The west\|east trending Hoh Xil basin is the largest redbeds basin in northern Tibet plateau. It is 400km in axial length and has maximum width of 200km, which extends along Jin zone, separated the Qiangtang from the Bayankara block. It accommodates more than 5000m of terrestrial sediments during the Eocene to Oligocene dated by preliminary magnetostratigraphy and minor fossils.Detailed sedimentological observation and lithic facies associations analysis of the Eocene Fenghuoshan Group show to have evolved vertically from alluvial fan system in the lowest part, into stacked megasequences of coarsening\|upward fan\|delta system in the middle and upper part. The braided fluvial conglomeratic deposits occur at intervals along the basin margin and grade basin ward interbedded sandstone and mudstone. The Oligocene Yaxicuo Group is locally present and forms as laterally elongate sub\|basins, which is of a maximum thickness of 2000m, as seen in the Wudaoliang and the Hantaishan area. Alluvial fan associations in this sub\|basin in the proximal part adjacent to the southern faulted border and prograded northward to floodplain in distal part.展开更多
Structure-based protein classification can be based on the similarities in primary, second or tertiary structures of proteins. A method using virtual-bond-angles series that transformed the protein space configuration...Structure-based protein classification can be based on the similarities in primary, second or tertiary structures of proteins. A method using virtual-bond-angles series that transformed the protein space configuration into a sequence was used for the classification of three-dimensional structures oi proteins. By transforming the main chains formed by C^a atoms of proteins into sequences, the series of virtual-bond-angles corresponding to the tertiary structure of the proteins were constructed. Then a distance-based hierarchical clustering method similar to Ward method was introduced to classify these virtual-bond-angles series of proteins. 200 files of protein structures were selected from Brookheaven protein data bank, and 11 clusters were classified.展开更多
Many karst geodes have been found in the pure Iimestone on the top Maokou formation (Permian) in the axial part of anticlines and lower part hydrological networks in Chongqing region. It is sometimes a reservoir natur...Many karst geodes have been found in the pure Iimestone on the top Maokou formation (Permian) in the axial part of anticlines and lower part hydrological networks in Chongqing region. It is sometimes a reservoir natural gas. Calcite megacryst decorates the wall of the geodes which believed to he formed in Tertiary.展开更多
In Gunung Sewu, which locates southeast of Yogyakarta, cone karst composed of the Tertiary pure limestone is utilized intensively for agriculture. High population has been supported by efficient agricultural landuse i...In Gunung Sewu, which locates southeast of Yogyakarta, cone karst composed of the Tertiary pure limestone is utilized intensively for agriculture. High population has been supported by efficient agricultural landuse in this area. The population in the high density areas is increasing until 1990. Especially, the higher steep slope and the top of cones have been utilized as fields by deforestation since few years, because of continuous rapid increase of population.展开更多
The development of tropical karst in Guilin could be dated back to middle Triassic, i.e. up to 240 million years, and the incipient karst landform was formed from the middle Triassic to the early Jurassic, a period wi...The development of tropical karst in Guilin could be dated back to middle Triassic, i.e. up to 240 million years, and the incipient karst landform was formed from the middle Triassic to the early Jurassic, a period with intensive karstification. Later, the karst in the area has experienced three major periods, that is, the weak period from the middle Jurassic to the late Cretaceous; the intensive period in the Tertiary which was significant to the formation of the old Li River; and the third period lasts the Quaternary period which has completed the typical tropical karst landform. Some ideas about the effect of paleo lake water to the formation of the tropical karst and the ages of caves on different levels in Guilin have been put forward.展开更多
There is still no consensus on the mechanisms that have led to the growth and rise of the 3 10 6km\+2 wide and 5000m high Tibet plateau.In one class of models,the whole lithosphere is inferred to deform as a thin visc...There is still no consensus on the mechanisms that have led to the growth and rise of the 3 10 6km\+2 wide and 5000m high Tibet plateau.In one class of models,the whole lithosphere is inferred to deform as a thin viscous sheet.Concurrent thickening of the crust and lithospheric mantle over a vast area absorbs most of the plate convergence.In the thickest region (Tibet),topographic rebound is subsequently triggered by convective removal of the thickened mantle.This is followed by relief collapse and extension.The rebound has a profound effect on climate.Only the final collapse is associated with strike\|slip faulting,which is thus seen as a shallow and minor side\|effect.In another class of models,strain localization along lithospheric shear zones,and decoupling between mantle and crust,are thought to govern the deformation of Asia.Strike\|slip faulting and thrusting combine to cause diachronic uplift of Tibet soon after the onset of collision.The crust thickens but the mantle beneath subducts.At any given time,a small number of boundaries extending to the base of the lithosphere absorb much of the convergence.展开更多
Aneuploid lines have been playing an importantrole in crop genetic studies and breedingutilization.Unfortunately,only several geneticmaterials of aneuploid can be used in Uplandcotton. So far,there are 16 monosomicsid...Aneuploid lines have been playing an importantrole in crop genetic studies and breedingutilization.Unfortunately,only several geneticmaterials of aneuploid can be used in Uplandcotton. So far,there are 16 monosomicsidentified in cotton.In order to fill the gap,wecarried on the irradiation research of展开更多
文摘The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.
文摘Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure Formations (Wan, 1985; Hao and Wan, 1985; Xu, Wan, et al. 1990). The K/T boundary in Gamba was studied by Wan Xiaoqiao (1988). This paper deals with the boundary in the Tingri region. Willems (1993) discussed the Cretaceous to Tertiary sequence in the Tingri region. In his work, the Upper Cretaceous to Lower Tertiary passage beds involved the Zongshan, Zhepure Shanpo, Jidula and Zhepure Shan Formations. The lithologies in the Tingri and Gamba regions are generally comparable, and we describe the boundary sequence in the Tingri region as follows:1\ Zongshan Formation (Campanian—Middle Maastrichtian) Hao and Wan (1985) first described this formation in Tingri. It consists of limestones equivalent to the strata in Gamba. The nomination of the Zongshan formation has been used in both regions. The Formation in Gamba ranges from Campanian to Late Maastrichtian age. In Tingri, however, the upper beds were referred to the Zhepure Shanpo Formation because they are clastic sediments (Willems, 1993). Planktonic foraminifera are abundant, such as Globotruncana spp. and Omphalocyclus sp.
文摘The Tertiary basins are distributed in the eastern margin of the Tibetan Plateau along the large\|scale arc\|shaped strike\|slip belt of the Qiangtang—Hengduan Shan—Jinshajiang—Red River belt. Most of basins were controlled by regional northwest\| and south\|north treading faults, and a few basins were constrained by northwest\| or north\|north\|east\|treading local faults.The detailed field mapping and sedimentologic observations for 6 typical Tertiary basins in eastern Tibet show that their types include depressive basins, rifting basins, pull\|apart and extensional basins related to strike\|slip faulting, and erosion\|residual basins. Recently, most of them are controlled by compression\| or thrust\|related margin faults in single side or double laterals of these basins. Not\|well\|developed strata in the Tertiary basins were deformed to form various tight folds and thrusts. High\|K magma intruded widely into the basins. The tectono\|sedimentary evolution of the Tertiary basins appears tempo\|spatially inhomogeneous. The preliminary model to interpret the Tertiary basin evolution is described as below.
文摘The Cenozoic Yanyuan basin is located in the huge Longmenshan—Jinpingshan nappetectonic belt along the eastern margin of the Qinghai—Tibet plateau. The basin is the largest and the best\|preserved intraorogenic basin above 2300m ASL.The basin has deposited different kinds of sediments with 1600m in depth. The early Tertiary strata were first named as Lijiang formation in 1961, and later named as Hongyanzi formation. The later Tertiary strata, the lignite\|bearing strata, were once named as Xigeda formation. Li Yougheng(1978) found some mammal fossils in the strata, so they named it Yanyuan formation. The Hongyanzi Formation which thickness is 1022m can be divided into five members according to the lithologic characters. The first one is mainly made of purplish\|red coarse conglomerates. The composition of gravel mainly consists of limestone and purplish\|red sandstone and marl. The second one consists of sandstone interbedded with conglomerate. The member has three cyclic sequences from conglomerate to sandstone. The composition of gravel of this member is mainly limestone. From bottom to top the degree of sorting and roundness tends to be well. In sandstones or sand lenticules the oblique bedding and trough cross\|bedding can be seen. The third one is the member of sandstone and mudstone. The sandstone is light purple while the mudstone is purplish red. Ripple marks can be seen in the sandstone. The forth one consists of conglomerate interbedded with mudstone, The conglomerate and the sandstone assume three cyclic sequences. The composition of the gravel is chiefly limestone. The fifth one is a member of light purple massive conglomerate. The composition of the gravel is limestone. The imbricate structure can be seen in the conglomerate. The strata belong to later Eocene epoch in accordance with the fossils of mammals, plants and ostracoda in it.
基金Project(2005CB623701) supported by the National Basic Research Program of China
文摘The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was investigated. The results show that the maximum recoveries of kaolinite for DEN, DPN and DRN are 93%, 88% and 84%, respectively, but that of DBN is very low. On the basis of zeta potential and FT-IR spectra, the ionization of surface hydroxyl and isomorphic exchange of surface ions account for the charging mechanisms of kaolinite surface. The adsorption mechanism of tertiary amines on kaolinite surface is mainly electrostatic. The isoelectric point （IEP） of kaolinite increases from 3.4 to some more positive points after the interaction of kaolinite with the four tertiary amines. The FT-IR spectra of kaolinite change with the presence of some new sharp shapes belonging to the tertiary amines. The inductive electronic effects and space-steric effects of -CH3, -C2H5, -C3H7 and -C7H7 bonding to N atom result in different collecting power of the four tertiary amines.
文摘Eocene Fenghuoshan Group and lower Oligocene Yaxicuo Group are represented by mainly fluvial, lacustrine and fan\|deltaic redbeds cropping out in Hoh Xil basin, the largest redbed basin in northern Tibet plateau. Lithic sandstone, lithic quartzose sandstone, conglomerate, as well as siltstone, consist of the major rock composition of the redbeds. The petrography of sandstone and conglomerate reveals the relationship between regional tectonic uplift events and the provenance of lower Tertiary redbeds.The outcrop rock data show that the detritus were derived from sedimentary rocks, volcanic rocks, and metamorphic rocks. Phyllite and quartzite rock fragments are most common in the metamorphic rock fragments .The sedimentary rock fragments are composed of chert, limestone, siltstone, and mudstone fragments. But volcanic rock fragments are minor and occasionally occur. In Hantaishan area, the northwestern part of Hoh Xil basin, clastic composition of sandstones and conglomerates testify to mainly southward and northeastward provenances. The metamorphic rock fragments, which are more common than volcanic and sedimentary rock fragments, can be directly correlated with metamorphic rock of Triassic metasedimentary Bayankara Group around the basin. In Fenghuoshan area, the southwestern part of the basin, there are less metamorphic rock fragment composition and more limestone fragments than in Hantaishan area.The limestone fragments were obviously derived from Carboniferous—Permian or Jurassic limestone beds. These limestone strata can not be found in the Bayankara block mass at which Hoh Xil basin locates, thus it is deduced that the limestone detritus were derived from the south, that is, Qiangtang blockmass.
文摘We focus on early Cenozoic uplift, erosion and growth of northern Tibet plateau by reconstructing paleo\|drainage pattern in the Hoh Xil basin. Stratigraphical infilling sequences and lithic type orogenic basins are determined largely by contemporaneous tectonic activity. It is therefore reasonable to infer that paleoflow variability record give useful information about regional tectonic events. We now report paleocurrent data from outcrop measurement of 4 expedition profiles across the basin during 1997—1998.The west\|east trending Hoh Xil basin is the largest redbeds basin in northern Tibet plateau. It is 400km in axial length and has maximum width of 200km, which extends along Jin zone, separated the Qiangtang from the Bayankara block. It accommodates more than 5000m of terrestrial sediments during the Eocene to Oligocene dated by preliminary magnetostratigraphy and minor fossils.Detailed sedimentological observation and lithic facies associations analysis of the Eocene Fenghuoshan Group show to have evolved vertically from alluvial fan system in the lowest part, into stacked megasequences of coarsening\|upward fan\|delta system in the middle and upper part. The braided fluvial conglomeratic deposits occur at intervals along the basin margin and grade basin ward interbedded sandstone and mudstone. The Oligocene Yaxicuo Group is locally present and forms as laterally elongate sub\|basins, which is of a maximum thickness of 2000m, as seen in the Wudaoliang and the Hantaishan area. Alluvial fan associations in this sub\|basin in the proximal part adjacent to the southern faulted border and prograded northward to floodplain in distal part.
文摘Structure-based protein classification can be based on the similarities in primary, second or tertiary structures of proteins. A method using virtual-bond-angles series that transformed the protein space configuration into a sequence was used for the classification of three-dimensional structures oi proteins. By transforming the main chains formed by C^a atoms of proteins into sequences, the series of virtual-bond-angles corresponding to the tertiary structure of the proteins were constructed. Then a distance-based hierarchical clustering method similar to Ward method was introduced to classify these virtual-bond-angles series of proteins. 200 files of protein structures were selected from Brookheaven protein data bank, and 11 clusters were classified.
文摘Many karst geodes have been found in the pure Iimestone on the top Maokou formation (Permian) in the axial part of anticlines and lower part hydrological networks in Chongqing region. It is sometimes a reservoir natural gas. Calcite megacryst decorates the wall of the geodes which believed to he formed in Tertiary.
文摘In Gunung Sewu, which locates southeast of Yogyakarta, cone karst composed of the Tertiary pure limestone is utilized intensively for agriculture. High population has been supported by efficient agricultural landuse in this area. The population in the high density areas is increasing until 1990. Especially, the higher steep slope and the top of cones have been utilized as fields by deforestation since few years, because of continuous rapid increase of population.
文摘The development of tropical karst in Guilin could be dated back to middle Triassic, i.e. up to 240 million years, and the incipient karst landform was formed from the middle Triassic to the early Jurassic, a period with intensive karstification. Later, the karst in the area has experienced three major periods, that is, the weak period from the middle Jurassic to the late Cretaceous; the intensive period in the Tertiary which was significant to the formation of the old Li River; and the third period lasts the Quaternary period which has completed the typical tropical karst landform. Some ideas about the effect of paleo lake water to the formation of the tropical karst and the ages of caves on different levels in Guilin have been put forward.
文摘There is still no consensus on the mechanisms that have led to the growth and rise of the 3 10 6km\+2 wide and 5000m high Tibet plateau.In one class of models,the whole lithosphere is inferred to deform as a thin viscous sheet.Concurrent thickening of the crust and lithospheric mantle over a vast area absorbs most of the plate convergence.In the thickest region (Tibet),topographic rebound is subsequently triggered by convective removal of the thickened mantle.This is followed by relief collapse and extension.The rebound has a profound effect on climate.Only the final collapse is associated with strike\|slip faulting,which is thus seen as a shallow and minor side\|effect.In another class of models,strain localization along lithospheric shear zones,and decoupling between mantle and crust,are thought to govern the deformation of Asia.Strike\|slip faulting and thrusting combine to cause diachronic uplift of Tibet soon after the onset of collision.The crust thickens but the mantle beneath subducts.At any given time,a small number of boundaries extending to the base of the lithosphere absorb much of the convergence.
文摘Aneuploid lines have been playing an importantrole in crop genetic studies and breedingutilization.Unfortunately,only several geneticmaterials of aneuploid can be used in Uplandcotton. So far,there are 16 monosomicsidentified in cotton.In order to fill the gap,wecarried on the irradiation research of
