Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predict...Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predictions of future dust concentration.However,these issues still remain relatively poorly known in Central Asia(CA).The extensive loess deposits on the CA pediments provide a promising archive to explore atmospheric dust dynamics and climatic conditions in the past and their association with loess formation.This study investigates the granulometric and magnetic properties of a loess section(named Osh section)in the Fergana Valley,which provides a sensitive record of atmospheric dust dynamics since 30 ka based on radiometric(AMS ^(14)C)dating.The frequency-dependent magnetic susceptibility(χfd)and the mean grain size are used to reconstruct the broadscale effective moisture and summer atmospheric dynamics pattern in CA,respectively.The results show that the precession forcing exerts a huge influence on the wind-regime variabilities in CA,but with different physical processes under the impact of the Northern Hemisphere ice sheet(NHIS)before and after 15 ka.The origin of the sedimentation rate variations in the Osh loess is also linked to the NHIS-modulated changes of the atmospheric circulation patterns.Either the strengthened westerlies or the increased surface roughness from higher vegetation cover in loess-deposition areas have significantly accelerated the loess accumulation.As a result,these complicated influence factors of sedimentation rate change in the Osh loess section,especially during the Holocene epoch,may hamper accessibility of the authentic dust emission flux and atmospheric dust concentration in CA.展开更多
The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went a...The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went active right-lateral strike-slip during the Paleozoic, with right-lateral movements being rejuvenated in the Late Cenozoic. Tectonic movements along the intracontinental strike-slip faults contribute to absorb part of the regional crustal shortening linked to the India-Eurasia collision; knowledge of strike-slip motions along the Ta- las-Fergana Fault are necessary for a complete assessment of the active deformation of the Tianshan orogen. To improve our understanding of the intracontinental deformation of the Tianshan mountain belt and the occurrence of strong earthquakes along the whole length of the Talas-Fergana Fault, we identify features of relief arising during strong paleoearthquakes along the Talas-Fergana Fault, fault segmentation, the length of seismogenic ruptures, and the energy and age of ancient catastrophes. We show that during neotectonic time the fault devel- oped as a dextral strike-slip fault, with possible dextral displacements spreading to secondary fault planes north of the main fault trace. We determine rates of Holocene and Late Pleistocene dextral movements, and our radi- ocarbon dating indicates tens of strong earthquakes occurring along the fault zone during and interval of 15800 years. The reoccurrence of strong earthquakes along the Talas-Fergana Fault zone during the second half of the Holocene is about 300 years. The next strong earthquake along the fault will most probably occur along its southeastern chain during the next several decades. Seismotectonic deformation parameters indicate that M〉7 earthquakes with oscillation intensity I〉IX have occurred.展开更多
The Talas Fergana/Karatau Fault,is a major tectonic boundary separating the Kazakh-Turan domain to the west from the Tian Shan domain to the east.During the Jurassic,movements along the fault led to the opening of sev...The Talas Fergana/Karatau Fault,is a major tectonic boundary separating the Kazakh-Turan domain to the west from the Tian Shan domain to the east.During the Jurassic,movements along the fault led to the opening of several basins.Still,the Mesozoic kinematics of the fault and the geodynamic mechanism that led to the opening of these basins are largely unconstrained.Located at its southwestern termination,the Yarkand-Fergana Basin is certainly the best exposed and however still poorly understood.In this study,we provide new sedimentological description of the Jurassic series from the northern part of the Yarkand-Fergana Basin as well as new palynological data.Following a Middle-Late Triassic period dominated by regional erosion,the onset of sedimentation in the Yarkand-Fergana Basin occurred during the Sinemurian(?)-Pliensbachian.The basin opened as a half graben controlled by the Talas Fergana/Karatau Fault and separated from the Fergana Basin by basement highs.Extension persisted during the late Pliensbachian-Middle Jurassic,leading to a general widening of the YarkandFergana Basin.Finally,Late Jurassic-Early Cretaceous renewed tectonic activity in the area led to the inversion of the north Yarkand-Fergana Basin.The Early to Middle Jurassic timing of development of the Yarkand-Fergana Basin suggests that the coeval movements along the Talas Fergana/Karatau Fault are not associated to the collision of the Qiangtang block along the southern margin of Eurasia.We favor the hypothesis of an opening controlled by transtension related to far field effects of back-arc extension along the Neo-Tethys subduction zone to the west.展开更多
Cotton water productivity was studied in Fergana Valley of Central Asia during the years of 2009, 2010 and 2011. Data was collected from 18 demonstration fields (13 in Uzbekistan, 5 in Tajikistan). The demonstration f...Cotton water productivity was studied in Fergana Valley of Central Asia during the years of 2009, 2010 and 2011. Data was collected from 18 demonstration fields (13 in Uzbekistan, 5 in Tajikistan). The demonstration field farmers implemented several improved agronomic and irrigation water management practices. The average values of crop yield, estimated crop consumptive use (ETa) and total water applied (TWA) for the demonstration sites were, respectively, 3700 kg/ha, 6360 m3/ha, and 8120 m3/ha. The range of values for TWA and ETa were, respectively, 5000 m3/ha to 12,000 m3/ha and 4500 m3/ha to 8000 m3/ha. A quadratic relationship was found between TWA and ETa. The average yield of the adjacent fields was 3300 kg/ha, whereas the average yield of cotton in Fergana Valley as a whole was 2900 kg/ha, indicating 28% and 14% increase in crop yield, respectively, from, demonstration fields and adjacent fields. There was no significant difference in crop yields between the wet years (2009 and 2010) and the dry year (2011), which is explained by the quadratic relationship between TWA and ETa. The water productivity values ranged from 0.35 kg/m3 to 0.89 kg/m3, indicating a significant potential for improving water productivity through agronomic and irrigation management interventions. The ratio of average ETa divided by average TWA gave an average application efficiency of 78% (some fields under-irrigated and some fields over-irrigated), the remaining 22% of water applied leaving the field. Since more than 60% of the water used for irrigation in Tajikistan and Uzbekistan is pumped from, even if all this 22% of water returns to the stream, substantial energy savings would accrue from improving the average application efficiency at field level. The range of values for TWA indicates the inequity in water distribution/accessibility. Addressing this inequity would also increase water productivity at field and project level.展开更多
The article examines the representatives of the genus of <i><span style="font-family:Verdana;">Scutellaria</span></i><span style="font-family:Verdana;"> L. distributed...The article examines the representatives of the genus of <i><span style="font-family:Verdana;">Scutellaria</span></i><span style="font-family:Verdana;"> L. distributed in the Ferghana Valley. On the basis of samples collected during field research and stored in the National Herbarium (TASH) Fund of the Institute of </span><span style="font-family:Verdana;">Botany</span><span style="font-family:Verdana;"> Academy Sciences Republic of Uzbekistan, the growth of 23 species in the region was noted. Representatives of the genus </span><i><span style="font-family:Verdana;">Scutellaria</span></i><span style="font-family:Verdana;"> L. are important due to the abundance of endemic species and their widespread use in modern pharmaceuticals. At the same time, opinions and comments on the study of natural resources of some species common in the valley are presented.</span>展开更多
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant Nos.XDB40000000 and XDB26000000)Natural Science Foundation of China(Grant Nos.41977385 and 41572162)+1 种基金Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0101)State Key Laboratory of Loess and Quaternary Geology(Grant No.SKLLQGPY2006).
文摘Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predictions of future dust concentration.However,these issues still remain relatively poorly known in Central Asia(CA).The extensive loess deposits on the CA pediments provide a promising archive to explore atmospheric dust dynamics and climatic conditions in the past and their association with loess formation.This study investigates the granulometric and magnetic properties of a loess section(named Osh section)in the Fergana Valley,which provides a sensitive record of atmospheric dust dynamics since 30 ka based on radiometric(AMS ^(14)C)dating.The frequency-dependent magnetic susceptibility(χfd)and the mean grain size are used to reconstruct the broadscale effective moisture and summer atmospheric dynamics pattern in CA,respectively.The results show that the precession forcing exerts a huge influence on the wind-regime variabilities in CA,but with different physical processes under the impact of the Northern Hemisphere ice sheet(NHIS)before and after 15 ka.The origin of the sedimentation rate variations in the Osh loess is also linked to the NHIS-modulated changes of the atmospheric circulation patterns.Either the strengthened westerlies or the increased surface roughness from higher vegetation cover in loess-deposition areas have significantly accelerated the loess accumulation.As a result,these complicated influence factors of sedimentation rate change in the Osh loess section,especially during the Holocene epoch,may hamper accessibility of the authentic dust emission flux and atmospheric dust concentration in CA.
基金supported by the NATO Science Partnership for Peace and Security Program(SfPSP 983142)the International Science and Technology Center(KR-2011)the Russian Foundation of Basic Research(RFBR-13-05-91168-GFEN_a)
文摘The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went active right-lateral strike-slip during the Paleozoic, with right-lateral movements being rejuvenated in the Late Cenozoic. Tectonic movements along the intracontinental strike-slip faults contribute to absorb part of the regional crustal shortening linked to the India-Eurasia collision; knowledge of strike-slip motions along the Ta- las-Fergana Fault are necessary for a complete assessment of the active deformation of the Tianshan orogen. To improve our understanding of the intracontinental deformation of the Tianshan mountain belt and the occurrence of strong earthquakes along the whole length of the Talas-Fergana Fault, we identify features of relief arising during strong paleoearthquakes along the Talas-Fergana Fault, fault segmentation, the length of seismogenic ruptures, and the energy and age of ancient catastrophes. We show that during neotectonic time the fault devel- oped as a dextral strike-slip fault, with possible dextral displacements spreading to secondary fault planes north of the main fault trace. We determine rates of Holocene and Late Pleistocene dextral movements, and our radi- ocarbon dating indicates tens of strong earthquakes occurring along the fault zone during and interval of 15800 years. The reoccurrence of strong earthquakes along the Talas-Fergana Fault zone during the second half of the Holocene is about 300 years. The next strong earthquake along the fault will most probably occur along its southeastern chain during the next several decades. Seismotectonic deformation parameters indicate that M〉7 earthquakes with oscillation intensity I〉IX have occurred.
文摘The Talas Fergana/Karatau Fault,is a major tectonic boundary separating the Kazakh-Turan domain to the west from the Tian Shan domain to the east.During the Jurassic,movements along the fault led to the opening of several basins.Still,the Mesozoic kinematics of the fault and the geodynamic mechanism that led to the opening of these basins are largely unconstrained.Located at its southwestern termination,the Yarkand-Fergana Basin is certainly the best exposed and however still poorly understood.In this study,we provide new sedimentological description of the Jurassic series from the northern part of the Yarkand-Fergana Basin as well as new palynological data.Following a Middle-Late Triassic period dominated by regional erosion,the onset of sedimentation in the Yarkand-Fergana Basin occurred during the Sinemurian(?)-Pliensbachian.The basin opened as a half graben controlled by the Talas Fergana/Karatau Fault and separated from the Fergana Basin by basement highs.Extension persisted during the late Pliensbachian-Middle Jurassic,leading to a general widening of the YarkandFergana Basin.Finally,Late Jurassic-Early Cretaceous renewed tectonic activity in the area led to the inversion of the north Yarkand-Fergana Basin.The Early to Middle Jurassic timing of development of the Yarkand-Fergana Basin suggests that the coeval movements along the Talas Fergana/Karatau Fault are not associated to the collision of the Qiangtang block along the southern margin of Eurasia.We favor the hypothesis of an opening controlled by transtension related to far field effects of back-arc extension along the Neo-Tethys subduction zone to the west.
文摘Cotton water productivity was studied in Fergana Valley of Central Asia during the years of 2009, 2010 and 2011. Data was collected from 18 demonstration fields (13 in Uzbekistan, 5 in Tajikistan). The demonstration field farmers implemented several improved agronomic and irrigation water management practices. The average values of crop yield, estimated crop consumptive use (ETa) and total water applied (TWA) for the demonstration sites were, respectively, 3700 kg/ha, 6360 m3/ha, and 8120 m3/ha. The range of values for TWA and ETa were, respectively, 5000 m3/ha to 12,000 m3/ha and 4500 m3/ha to 8000 m3/ha. A quadratic relationship was found between TWA and ETa. The average yield of the adjacent fields was 3300 kg/ha, whereas the average yield of cotton in Fergana Valley as a whole was 2900 kg/ha, indicating 28% and 14% increase in crop yield, respectively, from, demonstration fields and adjacent fields. There was no significant difference in crop yields between the wet years (2009 and 2010) and the dry year (2011), which is explained by the quadratic relationship between TWA and ETa. The water productivity values ranged from 0.35 kg/m3 to 0.89 kg/m3, indicating a significant potential for improving water productivity through agronomic and irrigation management interventions. The ratio of average ETa divided by average TWA gave an average application efficiency of 78% (some fields under-irrigated and some fields over-irrigated), the remaining 22% of water applied leaving the field. Since more than 60% of the water used for irrigation in Tajikistan and Uzbekistan is pumped from, even if all this 22% of water returns to the stream, substantial energy savings would accrue from improving the average application efficiency at field level. The range of values for TWA indicates the inequity in water distribution/accessibility. Addressing this inequity would also increase water productivity at field and project level.
文摘The article examines the representatives of the genus of <i><span style="font-family:Verdana;">Scutellaria</span></i><span style="font-family:Verdana;"> L. distributed in the Ferghana Valley. On the basis of samples collected during field research and stored in the National Herbarium (TASH) Fund of the Institute of </span><span style="font-family:Verdana;">Botany</span><span style="font-family:Verdana;"> Academy Sciences Republic of Uzbekistan, the growth of 23 species in the region was noted. Representatives of the genus </span><i><span style="font-family:Verdana;">Scutellaria</span></i><span style="font-family:Verdana;"> L. are important due to the abundance of endemic species and their widespread use in modern pharmaceuticals. At the same time, opinions and comments on the study of natural resources of some species common in the valley are presented.</span>