Water footprint of production can be used to identify pressure on national or regional water resources generated by production activities. Water stress is defined as the ratio of water use （the difference between a r...Water footprint of production can be used to identify pressure on national or regional water resources generated by production activities. Water stress is defined as the ratio of water use （the difference between a re- gional water footprint of production and a green water footprint） to renewable water resources available in a country or region. Water stress can be used to identify pressure on national or regional water resources generated by production activities. This paper estimates the water footprint of production and the water stress in China during the years 1985-2009. The result shows that China＇s water footprint of production increased from 781.58×109 m^3 in 1985 to 1109.76 × 10^9 m^3 in 2009. Mega-cities and regions with less agriculture production due to local climatic conditions （Tibet and Qinghai） had lower water footprint of production, while the provinces （Henan, Shandong） with higher agriculture production had higher footprint. Provinces with severe water stress increased from 6 in 1985 to 9 in 2009. High to severe water stress exists mainly in mega-cities and agricultural areas located in the downstream areas of the Yellow River and the Yangtze River in North and Central China. The outlook for water resources pressure in China is not optimistic, with areas of stress expanding from northern to southern of China.展开更多
The dating of the uplift onset of the Huangshan pluton in the southern part of Anhui Province associated with the collision between paleo-Pacific Block and the Eurasian Block is a fundamental issue to better understan...The dating of the uplift onset of the Huangshan pluton in the southern part of Anhui Province associated with the collision between paleo-Pacific Block and the Eurasian Block is a fundamental issue to better understand the uplift mechanisms and the regional tectonic evolution. Х^2 values of seven zircon fission track （ZFF） samples collected from the south part of the Huangshan pluton were all 〈5%. Based on the grain ages of four typical ZFr samples, three thermal overprints ranging in 113-123, 72-95 and 49-66 Ma were distinguished respectively using the binomial peak-fitting method in accordance with the tectonic thermal events after south China shifted into circum-Pacific tectonic region. Apatite fission track （AFT） study of the Huangshan pluton shows ages lie between 15±3 and 56±6 Ma with all Х^2 values 〉5%, and all are significantly younger than their host rock formation ages, indicating that the samples have experienced post-formation thermal history. Based on the AFT resuits and topography characteristics in the Huangshan pluton, three zones with different denudation intensities caused by the differential uplift of the fault blocks were recognized in this paper, indicating that denudation was driven by the increase in elevation significantly. Modeling of the AFT data shows that the earlier cooling phase took place in the early Cenozoic and involved 3.3, 3.8 and 6.0℃/Ma of cooling rates equivalent to the exhumation rates of 90, 104 and 167 m/Ma in different fault blocks. The last phase of cooling took place from -10 Ma with average cooling rate of -5.6℃/Ma, equivalent to average denudation rates of -156 m/Ma. The fission track results imply that the regional compression field plays an important role for the differential exhumation between individual fault blocks of the Huangshan pluton.展开更多
Combined apatite fission track （AFT） and （U-Th）/He （AHe） thermochronometries can be of great value for investigating the history of exhumation of orogenic belts. We evaluate the results of such a combined approa...Combined apatite fission track （AFT） and （U-Th）/He （AHe） thermochronometries can be of great value for investigating the history of exhumation of orogenic belts. We evaluate the results of such a combined approach through the study on rock sam- ples collected from the Baluntai section in the Tianshan Mountains, northwestern China. Our results show that AFT ages range from -60 to 40 Ma and Atte ages span -40-10 Ma. Based on the strict thermochronological constraints imposed by AHe ages, forward modeling of data derived from AFT analyses provides a well-constrained Cenozoic thermal history. The modeled re- sults reveal a history of relatively slow exhumation during the early Cenozoic times followed by a significantly accelerated exhumation process since the early Miocene with the rate increasing from 〈30 m/Myr to 〉 100 m/Myr, which is consistent with the inference from the exhumation rates calculated based on both AFT and AHe age data by age-closure temperature and mine- ral pair methods. Further accelerated exhumation since the late Miocene is recorded by an AHe age （-11 Ma） from the bottom of the Baluntai section. Together with the previous low-temperature thermochronological data from the other parts of the Tianshan Mountains, the rapid exhumation since the early Miocene is regarded as an important exhumation process likely pre- vailing within the whole range.展开更多
The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track （AFI） chronometry is widely used to study the latest cooling stages caused by tectonic process or by ex...The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track （AFI） chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and -3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozo- ic tectonic uplift of the mountains and regional climate change.展开更多
The present geothermal gradient and terrestrial heat flow was calculated of 18 wells in the Jianghan Basin.Thermal gradient distribution of the Jianghan Basin was obtained based on data of systematical steady-state te...The present geothermal gradient and terrestrial heat flow was calculated of 18 wells in the Jianghan Basin.Thermal gradient distribution of the Jianghan Basin was obtained based on data of systematical steady-state temperature and oil-test temperature.The basin-wide average thermal gradient in depth interval of 0-4000 m is 33.59℃/km.We report nine measured terrestrial heat flow values based on the data of detailed thermal conductivity and systematical steady-state temperature.These values vary from 41.9 to 60.9 mW/m 2 with a mean of 52.3±6.3 mW/m 2.However,thermal history analyses based on vitrinite reflectance(VR) and apatite fission track(AFT) data indicate that thermal gradient in the northern and southern Qianbei Fault reached its peak of ～36 and ～39℃/km respectively in the Middle Jurassic and the Oligocene,and it descended during the early Miocene to the present-time value.Furthermore,tectonic subsidence analysis reveals that the tectonic subsidence of the Jianghan Basin in the Cretaceous to early Miocene was characterized by synrift initial subsidence followed by the subsequent thermal subsidence.The thermal history and tectonic subsidence history of Jianghan Basin are of great significance to petroleum exploration and hydrocarbon source assessment,because they bear directly on issues of petroleum source rock maturation.Based on the thermal history and tectonic subsidence history,with the combination of geochemical and thermal parameters,the maturation and the hydrocarbon generation intensity evolution history of the P2d source rocks are modeled.The results show that the P2d source rocks are in a higher degree of maturation at present,and the Yuan'an and Herong sags are the two most important kitchens in the Late Jurassic,Xiaoban Sag is another most important kitchen during the Late Cretaceous to late Paleogene,and the Zhijiang and Mianyang sags are other two important hydrocarbon kitchens in the Late Cretaceous.The Mianyang Sag and Yichang Ramp are the favorable exploration targets in the future.This study may provide new insight for the understanding of the oil and gas exploration potential for the Jianghan Basin.展开更多
The uplift indicated by five AFT (apatite fission track) samples is more than 3400 m by multi-episodic uplift since Late Cretaceous in Zoige area; especially the processes of fast uplift in Late Cretaceous and Neogene...The uplift indicated by five AFT (apatite fission track) samples is more than 3400 m by multi-episodic uplift since Late Cretaceous in Zoige area; especially the processes of fast uplift in Late Cretaceous and Neogene have important influences on the stress of paleo-fluid. Based on field geology, macroscopic features of fracture, and geochemistry of fluid inclusions, we decipher the paleo-fluid process of episodic migration. In early uplift stage, the temperature of inclusions increased with the constant salinity, whilst both of them proportionally decreased in the mid-late stage, indicating the different tendency of heat-fluid warming and freshwater contamination at different time. Of particular importance are the features of episodic fluid flow, such as ESR ages, and features of multi-episodic migration that correspond well with the process of multi-episodic uplift. Thus, concerning the rock stress-strain behavior responding to uplift, we further discuss the spatio-temporal coupling effect of episodic migration and decompression in multi-episodic uplift, thereby to better understand petroleum geology in the region.展开更多
基金National Key Technology Research and Development Program of China(2016YFC0503403)Projects of China geological survey(DD20160106)
文摘Water footprint of production can be used to identify pressure on national or regional water resources generated by production activities. Water stress is defined as the ratio of water use （the difference between a re- gional water footprint of production and a green water footprint） to renewable water resources available in a country or region. Water stress can be used to identify pressure on national or regional water resources generated by production activities. This paper estimates the water footprint of production and the water stress in China during the years 1985-2009. The result shows that China＇s water footprint of production increased from 781.58×109 m^3 in 1985 to 1109.76 × 10^9 m^3 in 2009. Mega-cities and regions with less agriculture production due to local climatic conditions （Tibet and Qinghai） had lower water footprint of production, while the provinces （Henan, Shandong） with higher agriculture production had higher footprint. Provinces with severe water stress increased from 6 in 1985 to 9 in 2009. High to severe water stress exists mainly in mega-cities and agricultural areas located in the downstream areas of the Yellow River and the Yangtze River in North and Central China. The outlook for water resources pressure in China is not optimistic, with areas of stress expanding from northern to southern of China.
基金supported by National Natural Science Foundation of China(Grant Nos.40772134)Open Research Program of the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Grant No.200643)
文摘The dating of the uplift onset of the Huangshan pluton in the southern part of Anhui Province associated with the collision between paleo-Pacific Block and the Eurasian Block is a fundamental issue to better understand the uplift mechanisms and the regional tectonic evolution. Х^2 values of seven zircon fission track （ZFF） samples collected from the south part of the Huangshan pluton were all 〈5%. Based on the grain ages of four typical ZFr samples, three thermal overprints ranging in 113-123, 72-95 and 49-66 Ma were distinguished respectively using the binomial peak-fitting method in accordance with the tectonic thermal events after south China shifted into circum-Pacific tectonic region. Apatite fission track （AFT） study of the Huangshan pluton shows ages lie between 15±3 and 56±6 Ma with all Х^2 values 〉5%, and all are significantly younger than their host rock formation ages, indicating that the samples have experienced post-formation thermal history. Based on the AFT resuits and topography characteristics in the Huangshan pluton, three zones with different denudation intensities caused by the differential uplift of the fault blocks were recognized in this paper, indicating that denudation was driven by the increase in elevation significantly. Modeling of the AFT data shows that the earlier cooling phase took place in the early Cenozoic and involved 3.3, 3.8 and 6.0℃/Ma of cooling rates equivalent to the exhumation rates of 90, 104 and 167 m/Ma in different fault blocks. The last phase of cooling took place from -10 Ma with average cooling rate of -5.6℃/Ma, equivalent to average denudation rates of -156 m/Ma. The fission track results imply that the regional compression field plays an important role for the differential exhumation between individual fault blocks of the Huangshan pluton.
基金supported by National Natural Science Foundation of China(Grant No.41001002)China Postdoctoral Science Special Foundation(Grant No.201003277)
文摘Combined apatite fission track （AFT） and （U-Th）/He （AHe） thermochronometries can be of great value for investigating the history of exhumation of orogenic belts. We evaluate the results of such a combined approach through the study on rock sam- ples collected from the Baluntai section in the Tianshan Mountains, northwestern China. Our results show that AFT ages range from -60 to 40 Ma and Atte ages span -40-10 Ma. Based on the strict thermochronological constraints imposed by AHe ages, forward modeling of data derived from AFT analyses provides a well-constrained Cenozoic thermal history. The modeled re- sults reveal a history of relatively slow exhumation during the early Cenozoic times followed by a significantly accelerated exhumation process since the early Miocene with the rate increasing from 〈30 m/Myr to 〉 100 m/Myr, which is consistent with the inference from the exhumation rates calculated based on both AFT and AHe age data by age-closure temperature and mine- ral pair methods. Further accelerated exhumation since the late Miocene is recorded by an AHe age （-11 Ma） from the bottom of the Baluntai section. Together with the previous low-temperature thermochronological data from the other parts of the Tianshan Mountains, the rapid exhumation since the early Miocene is regarded as an important exhumation process likely pre- vailing within the whole range.
文摘The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track （AFI） chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and -3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozo- ic tectonic uplift of the mountains and regional climate change.
基金supported by National Natural Science Foundation of China(Grant No.41102152)Sinopec Marine Prospective Study Program(Grant No.2007CB411704)
文摘The present geothermal gradient and terrestrial heat flow was calculated of 18 wells in the Jianghan Basin.Thermal gradient distribution of the Jianghan Basin was obtained based on data of systematical steady-state temperature and oil-test temperature.The basin-wide average thermal gradient in depth interval of 0-4000 m is 33.59℃/km.We report nine measured terrestrial heat flow values based on the data of detailed thermal conductivity and systematical steady-state temperature.These values vary from 41.9 to 60.9 mW/m 2 with a mean of 52.3±6.3 mW/m 2.However,thermal history analyses based on vitrinite reflectance(VR) and apatite fission track(AFT) data indicate that thermal gradient in the northern and southern Qianbei Fault reached its peak of ～36 and ～39℃/km respectively in the Middle Jurassic and the Oligocene,and it descended during the early Miocene to the present-time value.Furthermore,tectonic subsidence analysis reveals that the tectonic subsidence of the Jianghan Basin in the Cretaceous to early Miocene was characterized by synrift initial subsidence followed by the subsequent thermal subsidence.The thermal history and tectonic subsidence history of Jianghan Basin are of great significance to petroleum exploration and hydrocarbon source assessment,because they bear directly on issues of petroleum source rock maturation.Based on the thermal history and tectonic subsidence history,with the combination of geochemical and thermal parameters,the maturation and the hydrocarbon generation intensity evolution history of the P2d source rocks are modeled.The results show that the P2d source rocks are in a higher degree of maturation at present,and the Yuan'an and Herong sags are the two most important kitchens in the Late Jurassic,Xiaoban Sag is another most important kitchen during the Late Cretaceous to late Paleogene,and the Zhijiang and Mianyang sags are other two important hydrocarbon kitchens in the Late Cretaceous.The Mianyang Sag and Yichang Ramp are the favorable exploration targets in the future.This study may provide new insight for the understanding of the oil and gas exploration potential for the Jianghan Basin.
文摘The uplift indicated by five AFT (apatite fission track) samples is more than 3400 m by multi-episodic uplift since Late Cretaceous in Zoige area; especially the processes of fast uplift in Late Cretaceous and Neogene have important influences on the stress of paleo-fluid. Based on field geology, macroscopic features of fracture, and geochemistry of fluid inclusions, we decipher the paleo-fluid process of episodic migration. In early uplift stage, the temperature of inclusions increased with the constant salinity, whilst both of them proportionally decreased in the mid-late stage, indicating the different tendency of heat-fluid warming and freshwater contamination at different time. Of particular importance are the features of episodic fluid flow, such as ESR ages, and features of multi-episodic migration that correspond well with the process of multi-episodic uplift. Thus, concerning the rock stress-strain behavior responding to uplift, we further discuss the spatio-temporal coupling effect of episodic migration and decompression in multi-episodic uplift, thereby to better understand petroleum geology in the region.
