Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded...Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded that (l)the Songpan-Garze fold belt has uplifted at least by 3-4 km with an uplift rate of no less than 0.3-0.4 mm/a since 10 Ma B.P.; (2) the Longmenshan thrust nappe belt has uplifted at least by 5-6 km with an uplift rate of more than 0.5- 0.6 mm /a since 10 Ma B.P.; (3) the Longmenshan detachment belt has uplifted by 1 - 2 km at a rate of 0.016-0.032 mm/a since 60 Ma B.P.; (4) the West Sichuan foreland basin has uplifted by 1.7-3 km at a rate of 0.028-0.05 mm/a since 60 Ma B.P.; (5) the uplift rate of the area on the west side of the Beichuan-Yingxiu-Xiaoguanzi fault for the last 10 Ma is 40 times as much as that on its east side; (6) the uplifting of the the Songpan - Garze fold belt and the subsidence of the West Sichuan foreland basin 60 Ma ago exhibit a mirro-image correlation, i.展开更多
Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corr...Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48-204.95 Ma at a rate of 10.22℃/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96-35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132-127.23 Ma at a rate of 94.34℃/Ma, and its rapid uplift occurred in 86-45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143-120.99 Ma at a rate of 19.51℃/Ma, and its rapid uplift occurred in 106-103.95 Ma and 20-0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.展开更多
In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock ...In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock lithozones can be distinguished in the northern part of the plateau. Cenozoic volcanic rocks and muscovite/two\|mica granites forming the three belts in pairs represent the northern and southern margins of the plateau in different periods. In fact, the tectonic setting of the northern part of the Qinghai\|Tibet plateau is significantly different from that of the southern part—Himalayas. The southern part has experienced subduction and continent\|continent collision. There are developed the Cenozoic S\|type granites (muscovite/two\|mica granites) there. But the northern part is characterized by Cenozoic basaltic magmatism which obviously comes from the upper mantle. Slight doming of the upper mantle is recognized underneath the northern part of the plateau, which is the result of resistance of the Tarim plate to the north direction\|sense movement of the Tibetan plate. And at the same time, the uplift machanism shows that the formation of the Qinghai\|Tibet plateau involved three orogenic stages (35-23 Ma, 23-10 Ma and <2 Ma) of uplift in the vertical direction and extension in the horizontal direction with the Gangdise\|Qiangtang orogenic belt as its core.展开更多
The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the ...The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the atmosphere has become important part of the global climatic change study.The paleowind belts are the comprising part of the past general circulation of the atmosphere and also the records of the circulation,therefore,their reconstruction will be helpful to the reconstruction of the general circulation of the atmosphere.In present years,the pattern of the general circulation of the atmosphere has attracted great concern from scientists.For example,Zhang Linyuan and Liu Dongsheng, based on the existence and inexistence of the Tibetan Plateau and paleogeography,divide the evolution of the general circulation of the atmosphere in eastern asia into two stages:the planetary wind stage before the uplift of the plateau and the monsoon stage after the uplift of the plateau which is subdivided into ancient monsoon and modern monsoon stages.While Dong Guangrong et al., Jiang Xinsheng et al. and Cooke et al, based on the latitudinal distribution of the Cretaceous and Tertiary deserts and the generation of arid climate,suggest that there was a subtropical high pressure zone across the eastern asia and was a planetary wind system,but have not found any direct record of the circulation.It is true that before the Early Tertiary,not only organism, but also inorganism,i.e.,biogeography and lithogeography, show strong zonal distribution.It can only indicate that zonal climate was evident at that time.Of course, as the climate is the result of the influences on the ground by zones of the circulation,it is reasonable to deduce the existence of zonal circulation,i.e. the the existence of the planetary wind system,from the zonal climate.But it would be much better if direct record of planetary wind system were found.Prevailing winds are the main geological agent for a desert which must leave deep stamps on the desert.The stamps on modern desert are reflected by dune migrating directions and on paleodesert by foreset dip directions..It is the most direct geological record for reconstructing paleowind belts and has been extensively used to reconstruct paleowind belts,paleogeography,paleoclimate and even to check the paleolatitude determined by paleomagnetism (for example, Opdyke and Runcorn, 1960; Creer, 1958; Pook, 1962; Bigarella and Salamuni,1961).展开更多
This paper mainly proposes six major regional geological events in the active continental-margin mantle uplift zone and discusses the oscillation nature of the evolution of Mesozoic volcanic basins and red basins, ori...This paper mainly proposes six major regional geological events in the active continental-margin mantle uplift zone and discusses the oscillation nature of the evolution of Mesozoic volcanic basins and red basins, origin of erosion in the late stage of red basins and mechanism of volcanism.展开更多
The Silurian hydrocarbon exploration in the northwest Tarim Basin had long been fruitless, till Well XSD1 drilled in 2018 in the Shajingzi structural belt, northwest Tarim Basin tapped industrial gas flow from the Sil...The Silurian hydrocarbon exploration in the northwest Tarim Basin had long been fruitless, till Well XSD1 drilled in 2018 in the Shajingzi structural belt, northwest Tarim Basin tapped industrial gas flow from the Silurian for the first time. The reservoir-forming model and resource extent need to be made clear urgently. Based on the comprehensive research of drilling,formation testing, geochemical data, and sedimentary and accumulation history, in combination with field surveys, experiments, structure interpretation and reconstruction of structure evolution, it is found that:(1) The northwest Tarim Basin had widespread tidal deltaic deposits in the Silurian period, which contain good reservoir-cap combinations;(2) the Shajingzi fault and associated faults connected the Cambrian-Ordovician source rocks in the Awati sag, and controlled the formation of Silurian structural traps, hence, the traps turned up along the structural belt in an orderly pattern and came together into contiguous tracts;(3) the Silurian petroleum in Shajingzi structural belt was dominated by gas, and the major accumulation period was the Himalayan period when the traps fixed in shape;(4) the Silurian gas resources in the Shajingzi belt were estimated at around 2.018×10^(11)m^(3), and Silurian gas resources of the northwest Tarim Basin were estimated at 2.03×10^(12)m^(3), implying huge exploration potential, so this area will become a major area for reserve and production increase from clastic strata in the basin;(5) with the Shajingzi fault of large scale and long active time connecting deep source rock layers, multiple formations in Lower Paleozoic of Shajingzi structural belt may have breakthroughs in hydrocarbon exploration.展开更多
This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapir...This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt.展开更多
The occurrence of landslides in Heifangtai plateau is primarily caused by the rise in water levels due to irrigation. To accurately understand the distribution of groundwater and its impact on the landslide hazard, a ...The occurrence of landslides in Heifangtai plateau is primarily caused by the rise in water levels due to irrigation. To accurately understand the distribution of groundwater and its impact on the landslide hazard, a combination of Electrical Resistivity Tomography(ERT), Induced Polarization(IP) and Surface Nuclear Magnetic Resonance(SNMR) methods were used in this study. By conducting a comprehensive analysis, the characteristics of water-bearing structure in vertical and groundwater distribution in horizontal were detected;and the influence of the groundwater on plateau and landslides was also identified. The results indicate that the groundwater occurs in the loess aquifer with a three-layer structure in vertical.Horizontally, the aquifer has a unified water table over the plateau, with a low water level in the north and high one in the south. The high resistivity bedrock uplift belt in the middle of the plateau forms a watershed,with the north side of the uplift belt being a relatively stable slope area with stable water content and fewer geological disasters. In contrast, the south side of the uplift belt is a disaster-prone region with vertical fissures well developed in the loess aquifers. The southern landslides are characterized by the interphase distribution of high and low electrical resistivity. The infiltration and discharge of groundwater result in the formation of a collapse belt in the low resistivity water-bearing structure of landslide, which causes the entire block with high resistivity and stable bedrock to slide. There was a newly formed landslide in a larger range at the landslide' s trailing edge. This study provides a scientific basis for the study of landslides mechanisms and disaster prevention by identifying the distribution characteristics of groundwater and analyzing its influence from a geophysical perspective in Heifangtai.展开更多
基金the National Natural Science Foundation of china (poject No. 49070140)
文摘Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded that (l)the Songpan-Garze fold belt has uplifted at least by 3-4 km with an uplift rate of no less than 0.3-0.4 mm/a since 10 Ma B.P.; (2) the Longmenshan thrust nappe belt has uplifted at least by 5-6 km with an uplift rate of more than 0.5- 0.6 mm /a since 10 Ma B.P.; (3) the Longmenshan detachment belt has uplifted by 1 - 2 km at a rate of 0.016-0.032 mm/a since 60 Ma B.P.; (4) the West Sichuan foreland basin has uplifted by 1.7-3 km at a rate of 0.028-0.05 mm/a since 60 Ma B.P.; (5) the uplift rate of the area on the west side of the Beichuan-Yingxiu-Xiaoguanzi fault for the last 10 Ma is 40 times as much as that on its east side; (6) the uplifting of the the Songpan - Garze fold belt and the subsidence of the West Sichuan foreland basin 60 Ma ago exhibit a mirro-image correlation, i.
文摘Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48-204.95 Ma at a rate of 10.22℃/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96-35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132-127.23 Ma at a rate of 94.34℃/Ma, and its rapid uplift occurred in 86-45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143-120.99 Ma at a rate of 19.51℃/Ma, and its rapid uplift occurred in 106-103.95 Ma and 20-0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.
文摘In northern Qinghai\|Tibet plateau there are developed Cenozoic volcanic rocks. They constitute a trachybasalt\|shoshonite\|latite\|trachydacite assemblage. According to the forming ages, three Cenozoic volcanic rock lithozones can be distinguished in the northern part of the plateau. Cenozoic volcanic rocks and muscovite/two\|mica granites forming the three belts in pairs represent the northern and southern margins of the plateau in different periods. In fact, the tectonic setting of the northern part of the Qinghai\|Tibet plateau is significantly different from that of the southern part—Himalayas. The southern part has experienced subduction and continent\|continent collision. There are developed the Cenozoic S\|type granites (muscovite/two\|mica granites) there. But the northern part is characterized by Cenozoic basaltic magmatism which obviously comes from the upper mantle. Slight doming of the upper mantle is recognized underneath the northern part of the plateau, which is the result of resistance of the Tarim plate to the north direction\|sense movement of the Tibetan plate. And at the same time, the uplift machanism shows that the formation of the Qinghai\|Tibet plateau involved three orogenic stages (35-23 Ma, 23-10 Ma and <2 Ma) of uplift in the vertical direction and extension in the horizontal direction with the Gangdise\|Qiangtang orogenic belt as its core.
文摘The global climatic change study is a hot point today.As the pattern of the general circulation of the atmosphere is the key factor for climate,the reconstruction of the pattern of the past general circulation of the atmosphere has become important part of the global climatic change study.The paleowind belts are the comprising part of the past general circulation of the atmosphere and also the records of the circulation,therefore,their reconstruction will be helpful to the reconstruction of the general circulation of the atmosphere.In present years,the pattern of the general circulation of the atmosphere has attracted great concern from scientists.For example,Zhang Linyuan and Liu Dongsheng, based on the existence and inexistence of the Tibetan Plateau and paleogeography,divide the evolution of the general circulation of the atmosphere in eastern asia into two stages:the planetary wind stage before the uplift of the plateau and the monsoon stage after the uplift of the plateau which is subdivided into ancient monsoon and modern monsoon stages.While Dong Guangrong et al., Jiang Xinsheng et al. and Cooke et al, based on the latitudinal distribution of the Cretaceous and Tertiary deserts and the generation of arid climate,suggest that there was a subtropical high pressure zone across the eastern asia and was a planetary wind system,but have not found any direct record of the circulation.It is true that before the Early Tertiary,not only organism, but also inorganism,i.e.,biogeography and lithogeography, show strong zonal distribution.It can only indicate that zonal climate was evident at that time.Of course, as the climate is the result of the influences on the ground by zones of the circulation,it is reasonable to deduce the existence of zonal circulation,i.e. the the existence of the planetary wind system,from the zonal climate.But it would be much better if direct record of planetary wind system were found.Prevailing winds are the main geological agent for a desert which must leave deep stamps on the desert.The stamps on modern desert are reflected by dune migrating directions and on paleodesert by foreset dip directions..It is the most direct geological record for reconstructing paleowind belts and has been extensively used to reconstruct paleowind belts,paleogeography,paleoclimate and even to check the paleolatitude determined by paleomagnetism (for example, Opdyke and Runcorn, 1960; Creer, 1958; Pook, 1962; Bigarella and Salamuni,1961).
文摘This paper mainly proposes six major regional geological events in the active continental-margin mantle uplift zone and discusses the oscillation nature of the evolution of Mesozoic volcanic basins and red basins, origin of erosion in the late stage of red basins and mechanism of volcanism.
基金Supported by the China Geological Survey Project (DD20190106,DD20190090)。
文摘The Silurian hydrocarbon exploration in the northwest Tarim Basin had long been fruitless, till Well XSD1 drilled in 2018 in the Shajingzi structural belt, northwest Tarim Basin tapped industrial gas flow from the Silurian for the first time. The reservoir-forming model and resource extent need to be made clear urgently. Based on the comprehensive research of drilling,formation testing, geochemical data, and sedimentary and accumulation history, in combination with field surveys, experiments, structure interpretation and reconstruction of structure evolution, it is found that:(1) The northwest Tarim Basin had widespread tidal deltaic deposits in the Silurian period, which contain good reservoir-cap combinations;(2) the Shajingzi fault and associated faults connected the Cambrian-Ordovician source rocks in the Awati sag, and controlled the formation of Silurian structural traps, hence, the traps turned up along the structural belt in an orderly pattern and came together into contiguous tracts;(3) the Silurian petroleum in Shajingzi structural belt was dominated by gas, and the major accumulation period was the Himalayan period when the traps fixed in shape;(4) the Silurian gas resources in the Shajingzi belt were estimated at around 2.018×10^(11)m^(3), and Silurian gas resources of the northwest Tarim Basin were estimated at 2.03×10^(12)m^(3), implying huge exploration potential, so this area will become a major area for reserve and production increase from clastic strata in the basin;(5) with the Shajingzi fault of large scale and long active time connecting deep source rock layers, multiple formations in Lower Paleozoic of Shajingzi structural belt may have breakthroughs in hydrocarbon exploration.
基金This study was a part of the Project Research on Deformation Dynamics on the North Margin of the Qinghai-Tibet Plateau(No,86-06-207)- a key Project of deep geology of the Ministry of Geology and Mineral Resources in the Eighth Five-Year Plan period(1991
文摘This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt.
基金supported and funded by the National Natural Science Foundation of China (Grant No: 42177346, 52009103)the Key Laboratory for Groundwater and Ecology in Arid and Semi-arid Areasthe China Geological Survey project (No: DD20190296)。
文摘The occurrence of landslides in Heifangtai plateau is primarily caused by the rise in water levels due to irrigation. To accurately understand the distribution of groundwater and its impact on the landslide hazard, a combination of Electrical Resistivity Tomography(ERT), Induced Polarization(IP) and Surface Nuclear Magnetic Resonance(SNMR) methods were used in this study. By conducting a comprehensive analysis, the characteristics of water-bearing structure in vertical and groundwater distribution in horizontal were detected;and the influence of the groundwater on plateau and landslides was also identified. The results indicate that the groundwater occurs in the loess aquifer with a three-layer structure in vertical.Horizontally, the aquifer has a unified water table over the plateau, with a low water level in the north and high one in the south. The high resistivity bedrock uplift belt in the middle of the plateau forms a watershed,with the north side of the uplift belt being a relatively stable slope area with stable water content and fewer geological disasters. In contrast, the south side of the uplift belt is a disaster-prone region with vertical fissures well developed in the loess aquifers. The southern landslides are characterized by the interphase distribution of high and low electrical resistivity. The infiltration and discharge of groundwater result in the formation of a collapse belt in the low resistivity water-bearing structure of landslide, which causes the entire block with high resistivity and stable bedrock to slide. There was a newly formed landslide in a larger range at the landslide' s trailing edge. This study provides a scientific basis for the study of landslides mechanisms and disaster prevention by identifying the distribution characteristics of groundwater and analyzing its influence from a geophysical perspective in Heifangtai.