The eastern margin of the Qaidam Basin lies in the key tectonic location connecting the Qinling, Qilian and East Kunlun orogens. The paper presents an investigation and analysis of the geologic structures of the area ...The eastern margin of the Qaidam Basin lies in the key tectonic location connecting the Qinling, Qilian and East Kunlun orogens. The paper presents an investigation and analysis of the geologic structures of the area and LA-ICP MS zircon U-Pb dating of Paleozoic and Mesozoic magmatisms of granitoids in the basement of the eastern Qaidam Basin on the basis of 16 granitoid samples collected from the South Qilian Mountains, the Qaidam Basin basement and the East Kunlun Mountains. According to the results in this paper, the basement of the basin, from the northern margin of the Qaidam Basin to the East Kunlun Mountains, has experienced at least three periods of intrusive activities of granitoids since the Early Paleozoic, i.e. the magmatisms occurring in the Late Cambrian （493.1±4.9 Ma）, the Silurian （422.9±8.0 Ma-420.4±4.6 Ma） and the Late Permian-Middle Triassic （257.8±4.0 Ma-228.8＋1.5 Ma）, respectively. Among them, the Late Permian - Middle Triassic granitoids form the main components of the basement of the basin. The statistics of dated zircons in this paper shows the intrusive magmatic activities in the basement of the basin have three peak ages of 244 Ma （main）, 418 Ma, and 493 Ma respectively. The dating results reveal that the Early Paleozoic magmatism of granitoids mainly occurred on the northern margin of the Qaidam Basin and the southern margin of the Qilian Mountains, with only weak indications in the East Kunlun Mountains. However, the distribution of Permo-Triassic （P-T） granitoids occupied across the whole basement of the eastern Qaidam Basin from the southern margin of the Qilian Mountains to the East Kunlun Mountains. An integrated analysis of the age distribution of P-T granitoids in the Qaidam Basin and its surrounding mountains shows that the earliest P-T magmatism （293.6-270 Ma） occurred in the northwestern part of the basin and expanded eastwards and southwards, resulting in the P-T intrusive magmatism that ran through the whole basin basement. As the Cenozoic basem展开更多
酒泉盆地南缘冲断带具有多层次的逆冲结构,包括浅层的远距离冲断系统、中层的近距离冲断系统和深层的原地冲断系统。远距离冲断系统由奥陶系和志留系构成,局部地区表现为飞来峰;近距离冲断系统由古生界和中生界构成,大部分隐伏在远距离...酒泉盆地南缘冲断带具有多层次的逆冲结构,包括浅层的远距离冲断系统、中层的近距离冲断系统和深层的原地冲断系统。远距离冲断系统由奥陶系和志留系构成,局部地区表现为飞来峰;近距离冲断系统由古生界和中生界构成,大部分隐伏在远距离冲断系统之下,局部地带以构造窗的形式出露地表,其变形样式主要为叠瓦状的冲断变形;原地冲断系统隐伏在近距离冲断系统和第四系之下,其南部的变形主要表现为双冲构造或堆垛构造,往NE方向变形逐渐简单,主要表现为断层传播褶皱和断层弯曲褶皱,前锋地带表现为三角带的突起构造。酒泉盆地南缘冲断带的变形是一个具有大缩短量的薄皮冲断系统,旱峡剖面的构造缩短量为52.7 km,缩短率为55.1%。酒泉盆地南缘冲断带的变形时期大致开始于9.0 M a,并以“前展式”向北扩张,变形时间向北变新,前锋断层开始活动时间约为8.3 M a。展开更多
The Qaidam Basin, located in the northern margin of the Qinghai-Tibet Plateau, is a large Mesozoic-Cenozoic basin, and bears huge thick Cenozoic strata. The geologic events of the Indian- Eurasian plate-plate collisio...The Qaidam Basin, located in the northern margin of the Qinghai-Tibet Plateau, is a large Mesozoic-Cenozoic basin, and bears huge thick Cenozoic strata. The geologic events of the Indian- Eurasian plate-plate collision since -55 Ma have been well recorded. Based on the latest progress in high-resolution stratigraphy, a technique of balanced section was applied to six pieces of northeast- southwest geologic seismic profiles in the central and eastern of the Qaidam Basin to reconstruct the crustal shortening deformation history during the Cenozoic collision. The results show that the Qaidam Basin began to shorten deformation nearly synchronous to the early collision, manifesting as a weak compression, the deformation increased significantly during the Middle and Late Eocene, and then weakened slightly and began to accelerate rapidly since the Late Miocene, especially since the Quaternary, reflecting this powerful compressional deformation and rapid uplift of the northern Tibetan Plateau around the Qaidam Basin.展开更多
Relief surveying and chronology study were carried out on the deformed river terraces across the Artushi anticline belt in the northwestern Tarim Basin. The crust shortening rate of this anticline belt since late Plei...Relief surveying and chronology study were carried out on the deformed river terraces across the Artushi anticline belt in the northwestern Tarim Basin. The crust shortening rate of this anticline belt since late Pleistocene was calculated to be up to 5-6 mm/a. The total crust shortening rate from the northwestern Tarim Basin to southwestern Tianshan since late Pleistocene was estimated to be over 10 mm/a.展开更多
Background Postprandial hypotension （PPH） occurs frequently in elderly people and may lead to syncope, falls, dizziness, weakness, angina pectoris, and stroke. Some studies suggest that the magnitude of the postpran...Background Postprandial hypotension （PPH） occurs frequently in elderly people and may lead to syncope, falls, dizziness, weakness, angina pectoris, and stroke. Some studies suggest that the magnitude of the postprandial fall in blood pressure （BP） is influenced by the rate at which glucose enters the small intestine. We hypothesized that acarbose （α-glucosidase inhibitor）, a hypoglycemic agent that decreases the rate of glucose absorption in the small intestine, would attenuate PPH in the elderly, and would be safe in the treatment. Methods Forty-three elderly in-patients with PPH were recruited. All of them were in relatively stable conditions. They had semi-liquid standard meals without and with acarbose for the two following days： screening day and intervention day. Blood pressure and heart rate （HR） were recorded at baseline and every 15 minutes for 120 minutes using a non-invasive ambulatory blood pressure monitoring system during the study, and ejection fraction （EF） and fractional shortening （FS） were measured by two dimensional echocardiography. Results Compared with the screening day, the falls in systolic, diastolic and mean arterial blood pressure （SBP, DBP, MAP） （all P 〈0.05） were significantly attenuated after taking acarbose during breakfast, so were MAP （P 〈0.05） during lunch, DBP （P 〈0.05） and MAP （P 〈0.05） during supper. The change of HR was not statistically significant after taking acarbose in three meals. EF and FS were positively correlated with the relief rate. The effective power was 63%, and the incidence of adverse drug reaction （ADR） was 9%. Conclusion Acarbose is effective and safe in the treatment of elderly patients with PPH.展开更多
The Ailaoshan-Red River（ASRR） shear zone is one of the major Southeast Asian tectonic discontinuities that have figured the present tectonic framework of the eastern Tibet.Several metamorphic massifs are distributed...The Ailaoshan-Red River（ASRR） shear zone is one of the major Southeast Asian tectonic discontinuities that have figured the present tectonic framework of the eastern Tibet.Several metamorphic massifs are distributed linearly along the shear zone,e.g.Xuelongshan,Diancangshan, Ailaoshan and Day Nui Con Voi from north to south.They bear a lot of lines of evidence for the tectonic evolution of the eastern Tibetan at different crustal levels in different tectonic stages.Controversy still exists on the deformation structures,microstructures and their relationship with metamorphisms along the ASRR.In this paper detailed microstructural and EBSD（Electron Backscattered Diffraction） fabric analysis of some highly sheared granitic rocks from different massifs along the ASRR are conducted.High temperature structures and microstructures are preserved in unsheared gneisses,in weakly sheared xenoliths or in some parts of the highly sheared rocks（mylonites）.Several types of high temperature quartz c-axis fabrics show symmetrical patterns or transitions from symmetrical to asymmetrical patterns.The former are attributed to coaxial deformation during regional shortening in an early stage of the Indian-Eurasian tectonic interaction and the latter are related to the transitions from coaxial compression to noncoaxial shearing during the post-collisional ASRR left lateral shearing.展开更多
By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt, China, we concluded that it had experienced five tectonic stages： （1） the formation stage （T3x） of the miniatur...By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt, China, we concluded that it had experienced five tectonic stages： （1） the formation stage （T3x） of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain; （2） the stable tectonic stage （J1） where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin; （3） the intense tectonic stage （J2-3）, namely the early Yanshan movement; （4） continuous tectonic movement （K-E）, namely the late Yanshan movement and early Himalayan movement; and （5） the formation of Longmen Mountain （N-Q）, namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain＇s formation. The Himalayan movement affected Longmen Mountain the most; the strata thrust intensively and were eroded severely. There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.展开更多
基金supports by the Basic Research Foundation of the Institute of Geomechanics,CAGS,China (DZLXJK200703)the National Natural Science Foundation of China(40342015)+1 种基金SinoProbe-Deep Exploration in China(SinoProbe-08)the National Science Foundation(USA) Instrumentation and Facilities Program (EAR-0443387)
文摘The eastern margin of the Qaidam Basin lies in the key tectonic location connecting the Qinling, Qilian and East Kunlun orogens. The paper presents an investigation and analysis of the geologic structures of the area and LA-ICP MS zircon U-Pb dating of Paleozoic and Mesozoic magmatisms of granitoids in the basement of the eastern Qaidam Basin on the basis of 16 granitoid samples collected from the South Qilian Mountains, the Qaidam Basin basement and the East Kunlun Mountains. According to the results in this paper, the basement of the basin, from the northern margin of the Qaidam Basin to the East Kunlun Mountains, has experienced at least three periods of intrusive activities of granitoids since the Early Paleozoic, i.e. the magmatisms occurring in the Late Cambrian （493.1±4.9 Ma）, the Silurian （422.9±8.0 Ma-420.4±4.6 Ma） and the Late Permian-Middle Triassic （257.8±4.0 Ma-228.8＋1.5 Ma）, respectively. Among them, the Late Permian - Middle Triassic granitoids form the main components of the basement of the basin. The statistics of dated zircons in this paper shows the intrusive magmatic activities in the basement of the basin have three peak ages of 244 Ma （main）, 418 Ma, and 493 Ma respectively. The dating results reveal that the Early Paleozoic magmatism of granitoids mainly occurred on the northern margin of the Qaidam Basin and the southern margin of the Qilian Mountains, with only weak indications in the East Kunlun Mountains. However, the distribution of Permo-Triassic （P-T） granitoids occupied across the whole basement of the eastern Qaidam Basin from the southern margin of the Qilian Mountains to the East Kunlun Mountains. An integrated analysis of the age distribution of P-T granitoids in the Qaidam Basin and its surrounding mountains shows that the earliest P-T magmatism （293.6-270 Ma） occurred in the northwestern part of the basin and expanded eastwards and southwards, resulting in the P-T intrusive magmatism that ran through the whole basin basement. As the Cenozoic basem
文摘酒泉盆地南缘冲断带具有多层次的逆冲结构,包括浅层的远距离冲断系统、中层的近距离冲断系统和深层的原地冲断系统。远距离冲断系统由奥陶系和志留系构成,局部地区表现为飞来峰;近距离冲断系统由古生界和中生界构成,大部分隐伏在远距离冲断系统之下,局部地带以构造窗的形式出露地表,其变形样式主要为叠瓦状的冲断变形;原地冲断系统隐伏在近距离冲断系统和第四系之下,其南部的变形主要表现为双冲构造或堆垛构造,往NE方向变形逐渐简单,主要表现为断层传播褶皱和断层弯曲褶皱,前锋地带表现为三角带的突起构造。酒泉盆地南缘冲断带的变形是一个具有大缩短量的薄皮冲断系统,旱峡剖面的构造缩短量为52.7 km,缩短率为55.1%。酒泉盆地南缘冲断带的变形时期大致开始于9.0 M a,并以“前展式”向北扩张,变形时间向北变新,前锋断层开始活动时间约为8.3 M a。
基金co-supported by the President Fund and Innovation Program of Chinese Academy of Sciences(no.:kzcx2-yw-104)the Chinese National Science Foundation grants(no.:40334038)the Science and Technology Key Project of Ministry of Education of China(no.:306016).
文摘The Qaidam Basin, located in the northern margin of the Qinghai-Tibet Plateau, is a large Mesozoic-Cenozoic basin, and bears huge thick Cenozoic strata. The geologic events of the Indian- Eurasian plate-plate collision since -55 Ma have been well recorded. Based on the latest progress in high-resolution stratigraphy, a technique of balanced section was applied to six pieces of northeast- southwest geologic seismic profiles in the central and eastern of the Qaidam Basin to reconstruct the crustal shortening deformation history during the Cenozoic collision. The results show that the Qaidam Basin began to shorten deformation nearly synchronous to the early collision, manifesting as a weak compression, the deformation increased significantly during the Middle and Late Eocene, and then weakened slightly and began to accelerate rapidly since the Late Miocene, especially since the Quaternary, reflecting this powerful compressional deformation and rapid uplift of the northern Tibetan Plateau around the Qaidam Basin.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49834005) the Commission of Science and Technology of China (Grant No. 96-913-07-01) and the Key Project of the Earthquake Joint Foundation (Grant No. 9507438).
文摘Relief surveying and chronology study were carried out on the deformed river terraces across the Artushi anticline belt in the northwestern Tarim Basin. The crust shortening rate of this anticline belt since late Pleistocene was calculated to be up to 5-6 mm/a. The total crust shortening rate from the northwestern Tarim Basin to southwestern Tianshan since late Pleistocene was estimated to be over 10 mm/a.
基金This work was supported by a grant from the National Natural Science Foundation of Hunan Province （No. 05JJ30158）.
文摘Background Postprandial hypotension （PPH） occurs frequently in elderly people and may lead to syncope, falls, dizziness, weakness, angina pectoris, and stroke. Some studies suggest that the magnitude of the postprandial fall in blood pressure （BP） is influenced by the rate at which glucose enters the small intestine. We hypothesized that acarbose （α-glucosidase inhibitor）, a hypoglycemic agent that decreases the rate of glucose absorption in the small intestine, would attenuate PPH in the elderly, and would be safe in the treatment. Methods Forty-three elderly in-patients with PPH were recruited. All of them were in relatively stable conditions. They had semi-liquid standard meals without and with acarbose for the two following days： screening day and intervention day. Blood pressure and heart rate （HR） were recorded at baseline and every 15 minutes for 120 minutes using a non-invasive ambulatory blood pressure monitoring system during the study, and ejection fraction （EF） and fractional shortening （FS） were measured by two dimensional echocardiography. Results Compared with the screening day, the falls in systolic, diastolic and mean arterial blood pressure （SBP, DBP, MAP） （all P 〈0.05） were significantly attenuated after taking acarbose during breakfast, so were MAP （P 〈0.05） during lunch, DBP （P 〈0.05） and MAP （P 〈0.05） during supper. The change of HR was not statistically significant after taking acarbose in three meals. EF and FS were positively correlated with the relief rate. The effective power was 63%, and the incidence of adverse drug reaction （ADR） was 9%. Conclusion Acarbose is effective and safe in the treatment of elderly patients with PPH.
基金supported by the National Key Basic Research and Development(973) Project (2009CB421001)National Natural Science Foundation of China(40872139)+2 种基金China Geological Survey (1212010661311)Ministry of Land and Resources (200811008)the Ministry of Education,Proiect 111 (B07011)
文摘The Ailaoshan-Red River（ASRR） shear zone is one of the major Southeast Asian tectonic discontinuities that have figured the present tectonic framework of the eastern Tibet.Several metamorphic massifs are distributed linearly along the shear zone,e.g.Xuelongshan,Diancangshan, Ailaoshan and Day Nui Con Voi from north to south.They bear a lot of lines of evidence for the tectonic evolution of the eastern Tibetan at different crustal levels in different tectonic stages.Controversy still exists on the deformation structures,microstructures and their relationship with metamorphisms along the ASRR.In this paper detailed microstructural and EBSD（Electron Backscattered Diffraction） fabric analysis of some highly sheared granitic rocks from different massifs along the ASRR are conducted.High temperature structures and microstructures are preserved in unsheared gneisses,in weakly sheared xenoliths or in some parts of the highly sheared rocks（mylonites）.Several types of high temperature quartz c-axis fabrics show symmetrical patterns or transitions from symmetrical to asymmetrical patterns.The former are attributed to coaxial deformation during regional shortening in an early stage of the Indian-Eurasian tectonic interaction and the latter are related to the transitions from coaxial compression to noncoaxial shearing during the post-collisional ASRR left lateral shearing.
基金support from the National Natural Science Foundation of China (grant No.40672143,40472107,and 40172076)the National Major Fundamental Research and Development Project (grant No.2005CB422107 and G1999043305)+1 种基金the Development Foundation of Key Laboratory for Hydrocarbon Accumulation of Education Ministry (grant No.2003-03)the Project of Southwestern Exploration and Development Division Company,SINOPEC (GJ-51-0602).
文摘By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt, China, we concluded that it had experienced five tectonic stages： （1） the formation stage （T3x） of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain; （2） the stable tectonic stage （J1） where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin; （3） the intense tectonic stage （J2-3）, namely the early Yanshan movement; （4） continuous tectonic movement （K-E）, namely the late Yanshan movement and early Himalayan movement; and （5） the formation of Longmen Mountain （N-Q）, namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain＇s formation. The Himalayan movement affected Longmen Mountain the most; the strata thrust intensively and were eroded severely. There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.
