Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions, and also exacerbated by mountainous exploitation activities. This paper concentrated on the characteri...Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions, and also exacerbated by mountainous exploitation activities. This paper concentrated on the characteristics, causes and mitigation of a catastrophic mine debris flow hazard at Longda Watershed in Songpan County, Sichuan Province, on 21 July 2011. This debris flow deposited in the front of the No.1 dam, silted the drainage channel for flood and then rushed into tailing sediment reservoir in the main channel and made the No.2 dam breached. The outburst debris flow blocked Fu River, formed dammed lake and generated outburst flood, which delivered heavy metals into the lower reaches of Fu River, polluted the drink water source of the population of over 1 million. The debris flow was characterized with a density of 1.87~2.15 t/m3 and a clay content of less than 1.63%. The peak velocity and flux at Longda Gully was over l0.0~10.9 m/s and 429.o~446.o m3/s, respectively, and the flux was about 700 m3/s in main channel, equaling to the flux of the probability of 1%. About 33o,ooorn3 solid materials was transported by debris flow and deposited in the drainage tunnel (120,000~130,000 m3), the front of No.1 dam (100,000 m3) and the mouth of the watershed (l00,000~110,000 m3), respectively. When the peak flux and magnitude of debris flow was more than 462 m3/s and 7,423 m3, respectively, it would block Fu River and produce a hazard chain which was composed of debris flow, dammed lake and outburst flood. Furthermore, the 21 July large-scale debris flow was triggered by rainstorm with an intensity of 21.2 mm/0.5 h and the solid materials of debris flow were provided by landslides, slope deposits, mining wastes and tailing sediments. The property losses were mainly originated from the silting of the drainage tunnel for flash flood but not for debris flow and the irrational location of tailing sediment reservoir. Therefore, the mitigation measures for mine debris flows were presented: (1) The disastrous debris flow watershed should be identified in planning period and prohibited from being taken as the site of mining factories; (2) The mining facilities are constructed at the safe areas or watersheds; (3) Scoria plots, concentrator factory and tailing sediment reservoir are constructed in safe areas where the protection measures be easily made against debris flows; (4) The appropriate system and plan of debris flow mitigation including monitoring, remote monitoring and early-warning and emergency plan is established; (5) The stability of waste dump and tailing sediment reservoir are monitored continuously to prevent mining debris flows.展开更多
The earth-rockfill dam is one of the primary dam types in the selection of high dams to be constructed in Western China, since it is characterized by favorable adaptability of the dam foundation; full utilization of l...The earth-rockfill dam is one of the primary dam types in the selection of high dams to be constructed in Western China, since it is characterized by favorable adaptability of the dam foundation; full utilization of local earth, rock, and building-excavated materials; low construction cost; and low cement consumption. Many major technical issues regarding earth-rockfill dams with a height of over 250 m were studied and solved successfully in the construction of the 261.5 m Nuozhadu earth core rockfill dam. This paper describes research achievements and basic conclusions; systematically summarizes the accumulated experiences from the construction of the Nuozhadu Dam and other high earth-rockfill dams; and discusses major technical issues, such as deformation control, seepage control, dam slope stability, safety and control of flood discharging, safety and quality control of dam construction, safety assessments, early warning, and other key technical difficulties. This study also provides a reference and technological support for the future construction of 300 m high earth-rockfill dams.展开更多
Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continent...Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continental shelf of the northwestern South China Sea(19°35'N,112°E) in May 2005 during the Wenchang Internal Wave Experiment using in-situ time series data from an array of temperature and salinity sensors,and an acoustic Doppler current profiler(ADCP).We summarized the characteristics of the ISWs and compared them with those of existing internal wave theories.Particular attention has been paid to characterizing solitons in terms of the relationship between shape and amplitude-width.Comparison between theoretical prediction and observation results shows that the high nonlinearity of these waves is better represented by the second-order extended Korteweg-de Vries(KdV) theory than the first-order KdV model.These results indicate that the northwestern South China Sea(SCS) is rich in highly nonlinear ISWs that are an indispensable part of the energy budget of the internal waves in the northern South China Sea.展开更多
In pursuit of more balanced regional development, China should base its regional policy during the period of the 12th Five-Year Plan on the principle of fairness, and tailor it to the specific characteristics of needy...In pursuit of more balanced regional development, China should base its regional policy during the period of the 12th Five-Year Plan on the principle of fairness, and tailor it to the specific characteristics of needy areas and development priority zones. The country "s master plan of developing the western region, revitalizing the northeast, supporting the rise of central China, and upgrading the east should continue.展开更多
Since the launching of the western regional development program in 1999, the Chinese government has implemented a series of policy measures related to finance, taxation, investment, banking, and other related fields. ...Since the launching of the western regional development program in 1999, the Chinese government has implemented a series of policy measures related to finance, taxation, investment, banking, and other related fields. This combination of policies has stimulated socioeconomic growth and ecological improvement in China's western regions and has effectively curbed the runaway gap between the east and west, even causing the gap to begin shrinking gradually. However, it should be noted that the development gap between China's eastern and western regions remains significant, as demonstrated by the west's low level of industrial^commercial development, local governments' limited capacity to provide public services, and endemic rural poverty. Thus, achieving the targets outlined in the western regional development program remains a challenging task. In the future, China's western development program should emphasize a higher standard of living and coordinated, inclusive growth across regions.展开更多
Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the...Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the wavelet method is used to analyze the series of earthquake data for the time period from 1900 to 2003 in the west of the Chinese mainland and its adjacent area (WCMAA), and to obtain the characteristic information for different time scales. In the past 103 years, there were four primary periods of regional earthquake activity in the area with durations of 42, 22, 7 and 14 years, respectively and the intensity of earthquake activity changing with time. It doesn’t make sense to talk about active or quiet periods of earthquake activity unless it is based on a specific time scale. In addition, the tendency analysis of earthquake activity using the primary period of seismic activity and wavelet coefficients of varied time scales indicates that the earthquake activity in this region will be high in the forthcoming years.展开更多
We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the wat...We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.展开更多
In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during...In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during the development process, the government of China launched the Great Campaign of Western Development (GCWD) in 2000. In this paper, we will evaluate the effects of the first 10 years' GCWD and use the latest Chinese annual data from 1978 to 2010 to investigate the problem of regional differentials in the development process, evaluate the effects of GCWD policy and test whether there is a regional Kuznets inverted-U curve in the regional development of China. The result shows that there are both good and bad news: the good news is that the inverted U-shaped curve of absolute differential between eastern and western areas finally emerges (the previous studies showed that the inverted-U curve did not appear and the differentials between eastern and western areas became worse) and the bad news is that the differential is in the first half of the inverted U-shaped curve in our choice of time span (1978-2010), that is, it is still in the situation of deterioration, and the turning better point will emerge in 2025. Although the western areas have benefitted from GCWD, the absolute gap has been still widened. To narrow the gap, the western areas should accelerate the industrial development and the government should adjust the policy and make more efforts to support the development of the industry in the western areas, especially cultivate and support the development of the western characteristic and advantageous industry rather than just supporting the construction of infrastructure in the western areas.展开更多
Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method o...Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern China, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.展开更多
China’s Western Development is a policy adopted to boost its less developed Western regions,that is,a systematic project and a longterm and arduous task.The development of compulsory education in China’s minority ar...China’s Western Development is a policy adopted to boost its less developed Western regions,that is,a systematic project and a longterm and arduous task.The development of compulsory education in China’s minority areas is the key to it.This paper attempts to use the beneficial experience of developing compulsory education support system of other countries for reference so as to explore financial support system suitable for the situation of China’s compulsory education in minority areas.展开更多
The Neoproterozoic Kangdian Rift Basin is a continental rift basin in the western Yangtze Continent.Determining its time of opening and subsequent filling pattern is an important aspect of understanding the formation ...The Neoproterozoic Kangdian Rift Basin is a continental rift basin in the western Yangtze Continent.Determining its time of opening and subsequent filling pattern is an important aspect of understanding the formation and evolution of the Yangtze Continent,South China.The Luliang Formation is the early filling in the eastern part of this rift basin,and its deposition age and filling sequence are significant for studies of the regional stratigraphic correlation,opening time,and filling pattern of this basin.Having been correlated to the upper part of the Mesoproterozoic Kunyang Group or to the Neoproterozoic Chengjiang Formation,the age and regional stratigraphic correlation of the Luliang Formation have long been uncertain.This is due to a lack of reliable absolute age constraints.To address this issue,the first zircon SHRIMP U-Pb geochronology has been established for this formation,yielding two high-precision isotopic ages of 818.6±9.2 and 805±14 Ma for the tuff layers at the bottoms of the lower and upper members of the Luliang Formation,respectively.Given the error factor,the bottom age of the lower member of the Luliang Formation can be interpreted as ca.820 Ma,corresponding to the bottom age of the lower part of the Banxi Group,which is the early filling of the Neoproterozoic Xianggui Rift Basin,a representative basin of the Neoproterozoic rift basins in the Yangtze Continent,South China.The bottom age of the upper member of the Luliang Formation can be interpreted as ca.800±5 Ma,corresponding to the bottom age of the Chengjiang Formation in the western part of the Neoproterozoic Kangdian Rift Basin and also corresponding to the bottom age of the upper part of the Banxi Group in the Neoproterozoic Xianggui Rift Basin.These ages indicate that the Neoproterozoic Kangdian Rift Basin shares the same opening time and filling sequences as those of the other Neoproterozoic rift basins in South China.Basin analysis shows that the Neoproterozoic Kangdian Rift Basin is a typical half-graben basin,with its main boundary fault in the west and basin center in the east.This basin consisted of mini unidirectional half-graben basins in its juvenile stage and simplified to become a large united half-graben basin in its mature stage,i.e.,a supradetachment basin.展开更多
Tarim Large Igneous Province (TLIP) is the second Late Paleozoic LIPs in China after the recognition of Emeishan LIP, and is a hot research topic in geosciences. On the basis of the analysis of research history abou...Tarim Large Igneous Province (TLIP) is the second Late Paleozoic LIPs in China after the recognition of Emeishan LIP, and is a hot research topic in geosciences. On the basis of the analysis of research history about TLIP, this paper summarizes the re- search result during last twenty years and suggests the key research area in the future. The residual distribution range of TLIP is up to 250000 km2, and the largest residual thickness is 780 m. The eruption of basalt happened during 290-288 Ma and be- longs to LIPs magmatic event with fast eruption of magma. The lithological units of the TLIP include basalt, diabase, layered intrusive rock, breccia pipe mica-olivine pyroxenite, olivine pyroxenite, gabbro, ultramafic dyke, quartz syenite, quartz syenite porphyry and bimodal dyke. The basalt and diabase of TLIP exhibit OIB-like trace element patterns and enrichment of LILE and HFSE, and mainly belong to high TiO2 series. There is an obvious difference in isotope among the basalt from Keping and the basalt and dibase from the northern Tarim Basin. The basalt from Keping with negative eNa and high REE value derives from enriched mantle, and the diabase and basalt from the northern Tarim Basin with positive ENa and low REE value axe re- lated to depleted mantle. The crust uplifting in the Early Permian and the development of picrite and large scale dyke and for- mation of large scale V-Ti-Magnetite deposit in Wajilitag area support the view that the TLIP is related to mantle plume. The TLIP has a temporal-spatial relationship with Permian basic to ultra-basic igneous rock, which is distributed widely in Central Asia, and they represent a tectono-magmatic event with very important geodynamic setting. This paper also suggests that the deep geological process, the relation with mantle plume, mineralization, the relation with environmental change and biological evolution, and the geodynamics of the TLIP will be the key research topics in the future.展开更多
Twenty-three giant panda cubs pose for a Chinese New Year photo at the Chengdu Research Base of Giant Panda Breeding in southwest China’s Sichuan Province on January 20.The cubs were all born at the base in 2016.
基金supported by National Basic Research Program of China (2011CB409902)National Key Technologies R & D Program of China (2012BAK10B04)
文摘Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions, and also exacerbated by mountainous exploitation activities. This paper concentrated on the characteristics, causes and mitigation of a catastrophic mine debris flow hazard at Longda Watershed in Songpan County, Sichuan Province, on 21 July 2011. This debris flow deposited in the front of the No.1 dam, silted the drainage channel for flood and then rushed into tailing sediment reservoir in the main channel and made the No.2 dam breached. The outburst debris flow blocked Fu River, formed dammed lake and generated outburst flood, which delivered heavy metals into the lower reaches of Fu River, polluted the drink water source of the population of over 1 million. The debris flow was characterized with a density of 1.87~2.15 t/m3 and a clay content of less than 1.63%. The peak velocity and flux at Longda Gully was over l0.0~10.9 m/s and 429.o~446.o m3/s, respectively, and the flux was about 700 m3/s in main channel, equaling to the flux of the probability of 1%. About 33o,ooorn3 solid materials was transported by debris flow and deposited in the drainage tunnel (120,000~130,000 m3), the front of No.1 dam (100,000 m3) and the mouth of the watershed (l00,000~110,000 m3), respectively. When the peak flux and magnitude of debris flow was more than 462 m3/s and 7,423 m3, respectively, it would block Fu River and produce a hazard chain which was composed of debris flow, dammed lake and outburst flood. Furthermore, the 21 July large-scale debris flow was triggered by rainstorm with an intensity of 21.2 mm/0.5 h and the solid materials of debris flow were provided by landslides, slope deposits, mining wastes and tailing sediments. The property losses were mainly originated from the silting of the drainage tunnel for flash flood but not for debris flow and the irrational location of tailing sediment reservoir. Therefore, the mitigation measures for mine debris flows were presented: (1) The disastrous debris flow watershed should be identified in planning period and prohibited from being taken as the site of mining factories; (2) The mining facilities are constructed at the safe areas or watersheds; (3) Scoria plots, concentrator factory and tailing sediment reservoir are constructed in safe areas where the protection measures be easily made against debris flows; (4) The appropriate system and plan of debris flow mitigation including monitoring, remote monitoring and early-warning and emergency plan is established; (5) The stability of waste dump and tailing sediment reservoir are monitored continuously to prevent mining debris flows.
文摘The earth-rockfill dam is one of the primary dam types in the selection of high dams to be constructed in Western China, since it is characterized by favorable adaptability of the dam foundation; full utilization of local earth, rock, and building-excavated materials; low construction cost; and low cement consumption. Many major technical issues regarding earth-rockfill dams with a height of over 250 m were studied and solved successfully in the construction of the 261.5 m Nuozhadu earth core rockfill dam. This paper describes research achievements and basic conclusions; systematically summarizes the accumulated experiences from the construction of the Nuozhadu Dam and other high earth-rockfill dams; and discusses major technical issues, such as deformation control, seepage control, dam slope stability, safety and control of flood discharging, safety and quality control of dam construction, safety assessments, early warning, and other key technical difficulties. This study also provides a reference and technological support for the future construction of 300 m high earth-rockfill dams.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX1-YW-12)the National High Technology Research and Development Program of China (863 program) (No.2008AA09A401,No.2006AA09A109)
文摘Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continental shelf of the northwestern South China Sea(19°35'N,112°E) in May 2005 during the Wenchang Internal Wave Experiment using in-situ time series data from an array of temperature and salinity sensors,and an acoustic Doppler current profiler(ADCP).We summarized the characteristics of the ISWs and compared them with those of existing internal wave theories.Particular attention has been paid to characterizing solitons in terms of the relationship between shape and amplitude-width.Comparison between theoretical prediction and observation results shows that the high nonlinearity of these waves is better represented by the second-order extended Korteweg-de Vries(KdV) theory than the first-order KdV model.These results indicate that the northwestern South China Sea(SCS) is rich in highly nonlinear ISWs that are an indispensable part of the energy budget of the internal waves in the northern South China Sea.
文摘In pursuit of more balanced regional development, China should base its regional policy during the period of the 12th Five-Year Plan on the principle of fairness, and tailor it to the specific characteristics of needy areas and development priority zones. The country "s master plan of developing the western region, revitalizing the northeast, supporting the rise of central China, and upgrading the east should continue.
文摘Since the launching of the western regional development program in 1999, the Chinese government has implemented a series of policy measures related to finance, taxation, investment, banking, and other related fields. This combination of policies has stimulated socioeconomic growth and ecological improvement in China's western regions and has effectively curbed the runaway gap between the east and west, even causing the gap to begin shrinking gradually. However, it should be noted that the development gap between China's eastern and western regions remains significant, as demonstrated by the west's low level of industrial^commercial development, local governments' limited capacity to provide public services, and endemic rural poverty. Thus, achieving the targets outlined in the western regional development program remains a challenging task. In the future, China's western development program should emphasize a higher standard of living and coordinated, inclusive growth across regions.
文摘Wavelets are a useful tool for analyzing the time-frequency of a non-stable series and are widely applied in many fields. The process of earthquake preparation and occurrence is a non-linear process. In the paper, the wavelet method is used to analyze the series of earthquake data for the time period from 1900 to 2003 in the west of the Chinese mainland and its adjacent area (WCMAA), and to obtain the characteristic information for different time scales. In the past 103 years, there were four primary periods of regional earthquake activity in the area with durations of 42, 22, 7 and 14 years, respectively and the intensity of earthquake activity changing with time. It doesn’t make sense to talk about active or quiet periods of earthquake activity unless it is based on a specific time scale. In addition, the tendency analysis of earthquake activity using the primary period of seismic activity and wavelet coefficients of varied time scales indicates that the earthquake activity in this region will be high in the forthcoming years.
基金funded by the“Technology Supporting Programme” of the “State Wetland Conservation Project for Lashihai Wetland”
文摘We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.
文摘In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during the development process, the government of China launched the Great Campaign of Western Development (GCWD) in 2000. In this paper, we will evaluate the effects of the first 10 years' GCWD and use the latest Chinese annual data from 1978 to 2010 to investigate the problem of regional differentials in the development process, evaluate the effects of GCWD policy and test whether there is a regional Kuznets inverted-U curve in the regional development of China. The result shows that there are both good and bad news: the good news is that the inverted U-shaped curve of absolute differential between eastern and western areas finally emerges (the previous studies showed that the inverted-U curve did not appear and the differentials between eastern and western areas became worse) and the bad news is that the differential is in the first half of the inverted U-shaped curve in our choice of time span (1978-2010), that is, it is still in the situation of deterioration, and the turning better point will emerge in 2025. Although the western areas have benefitted from GCWD, the absolute gap has been still widened. To narrow the gap, the western areas should accelerate the industrial development and the government should adjust the policy and make more efforts to support the development of the industry in the western areas, especially cultivate and support the development of the western characteristic and advantageous industry rather than just supporting the construction of infrastructure in the western areas.
基金supported by National Key Technology Research and Development Program of China (Grant Nos. 2008BAC35B01-8 and 2006BAC01B02-04-03)
文摘Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern China, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.
文摘China’s Western Development is a policy adopted to boost its less developed Western regions,that is,a systematic project and a longterm and arduous task.The development of compulsory education in China’s minority areas is the key to it.This paper attempts to use the beneficial experience of developing compulsory education support system of other countries for reference so as to explore financial support system suitable for the situation of China’s compulsory education in minority areas.
基金supported by National Natural Science Foundation of China(Grant Nos.4103031541072088)China Geological Survey(Grant No.1212011121105)
文摘The Neoproterozoic Kangdian Rift Basin is a continental rift basin in the western Yangtze Continent.Determining its time of opening and subsequent filling pattern is an important aspect of understanding the formation and evolution of the Yangtze Continent,South China.The Luliang Formation is the early filling in the eastern part of this rift basin,and its deposition age and filling sequence are significant for studies of the regional stratigraphic correlation,opening time,and filling pattern of this basin.Having been correlated to the upper part of the Mesoproterozoic Kunyang Group or to the Neoproterozoic Chengjiang Formation,the age and regional stratigraphic correlation of the Luliang Formation have long been uncertain.This is due to a lack of reliable absolute age constraints.To address this issue,the first zircon SHRIMP U-Pb geochronology has been established for this formation,yielding two high-precision isotopic ages of 818.6±9.2 and 805±14 Ma for the tuff layers at the bottoms of the lower and upper members of the Luliang Formation,respectively.Given the error factor,the bottom age of the lower member of the Luliang Formation can be interpreted as ca.820 Ma,corresponding to the bottom age of the lower part of the Banxi Group,which is the early filling of the Neoproterozoic Xianggui Rift Basin,a representative basin of the Neoproterozoic rift basins in the Yangtze Continent,South China.The bottom age of the upper member of the Luliang Formation can be interpreted as ca.800±5 Ma,corresponding to the bottom age of the Chengjiang Formation in the western part of the Neoproterozoic Kangdian Rift Basin and also corresponding to the bottom age of the upper part of the Banxi Group in the Neoproterozoic Xianggui Rift Basin.These ages indicate that the Neoproterozoic Kangdian Rift Basin shares the same opening time and filling sequences as those of the other Neoproterozoic rift basins in South China.Basin analysis shows that the Neoproterozoic Kangdian Rift Basin is a typical half-graben basin,with its main boundary fault in the west and basin center in the east.This basin consisted of mini unidirectional half-graben basins in its juvenile stage and simplified to become a large united half-graben basin in its mature stage,i.e.,a supradetachment basin.
基金supported by the National Natural Science Foundation of China(Grant No.40930315)National Basic Research Program of China(Grant Nos.2007CB411303&2011CB808902)
文摘Tarim Large Igneous Province (TLIP) is the second Late Paleozoic LIPs in China after the recognition of Emeishan LIP, and is a hot research topic in geosciences. On the basis of the analysis of research history about TLIP, this paper summarizes the re- search result during last twenty years and suggests the key research area in the future. The residual distribution range of TLIP is up to 250000 km2, and the largest residual thickness is 780 m. The eruption of basalt happened during 290-288 Ma and be- longs to LIPs magmatic event with fast eruption of magma. The lithological units of the TLIP include basalt, diabase, layered intrusive rock, breccia pipe mica-olivine pyroxenite, olivine pyroxenite, gabbro, ultramafic dyke, quartz syenite, quartz syenite porphyry and bimodal dyke. The basalt and diabase of TLIP exhibit OIB-like trace element patterns and enrichment of LILE and HFSE, and mainly belong to high TiO2 series. There is an obvious difference in isotope among the basalt from Keping and the basalt and dibase from the northern Tarim Basin. The basalt from Keping with negative eNa and high REE value derives from enriched mantle, and the diabase and basalt from the northern Tarim Basin with positive ENa and low REE value axe re- lated to depleted mantle. The crust uplifting in the Early Permian and the development of picrite and large scale dyke and for- mation of large scale V-Ti-Magnetite deposit in Wajilitag area support the view that the TLIP is related to mantle plume. The TLIP has a temporal-spatial relationship with Permian basic to ultra-basic igneous rock, which is distributed widely in Central Asia, and they represent a tectono-magmatic event with very important geodynamic setting. This paper also suggests that the deep geological process, the relation with mantle plume, mineralization, the relation with environmental change and biological evolution, and the geodynamics of the TLIP will be the key research topics in the future.
文摘Twenty-three giant panda cubs pose for a Chinese New Year photo at the Chengdu Research Base of Giant Panda Breeding in southwest China’s Sichuan Province on January 20.The cubs were all born at the base in 2016.