Relying on rich tourism resources of the Dabie Mountains to accelerate industrialized poverty alleviation and development is the inevitable choice of promoting regional economic and social leapfrog development. The re...Relying on rich tourism resources of the Dabie Mountains to accelerate industrialized poverty alleviation and development is the inevitable choice of promoting regional economic and social leapfrog development. The realistic basis of pro-poor tourism of the Dabie Mountains is already ready and continuously strengthened. This paper, based on domestic and foreign pro-poor tourism practices, put forward the development path to pro-poor-tourism of Dabie Mountains of "establishing tourism development platform with the government as the leading factor; establishing the benefit sharing mechanism of pro-poor tourism with community participation as the main line; improving the community residents' professionalism in engaging in tourism with local residents as the main body; enhancing the overall effectiveness of pro-poor tourism with tourism as the principal industry".展开更多
Petrologic geochemistry and isotopic chronology of the eclogites sug ge st that most of the eclogites in northern Dabie Mountains produced from the Tria ssic Yangtze subducted continental crust (lower crust and formed...Petrologic geochemistry and isotopic chronology of the eclogites sug ge st that most of the eclogites in northern Dabie Mountains produced from the Tria ssic Yangtze subducted continental crust (lower crust and formed during the deep subduction) and the metamorphosed mafic untramafic belt with eclogite, marble and meta peridotite blocks around the Mozitan Xiaotian fault zone may represen t the meta tectonic melange produced during the active subduction of an ancient oceanic slab and subsequent collision between the Yangtze and North China conti nental plates. The cooling history of the eclogites from ～900 ℃ to 300 ℃ can b e subdivided into three stages: one isothermal stage and two rapid cooling stage s. The initial stage between (230±6) and 210 Ma was a near isothermal or tempe rature rise process corresponding to the retrograded metamorphism of granulite facies with a rapid uplift of 4 mm/a, then two fast cooling stages occurred with cooling rate of ～10 ℃/Ma during 210 Ma to (172±3) Ma and ～4 ℃/Ma durin g (172±3) Ma to 130 Ma. After the peak metamorphism of eclogite facies, their in itial isothermal stage with slower uplift rate and cooling rate and high T overprinting of granulite facies metamorphism is the major difference between t he eclogites in northern Dabie Mountains from those in southern Dabie Mountains. This may be one of the most important reasons to preserve few evidences of earl ier ultrahigh pressure metamorphism.展开更多
After the integration of petrographic study, geothermobarometry and Gibbs method, the synthetic P-T paths for the rocks from different geological profiles in the North Qilian, China, have been derived. The composite P...After the integration of petrographic study, geothermobarometry and Gibbs method, the synthetic P-T paths for the rocks from different geological profiles in the North Qilian, China, have been derived. The composite P-T paths from different methods indicate that all the high-pressure rocks in the Qilian area recorded P-T paths with clockwise loops starting at the blueschist facies, later reaching peak metamorphism at the blueschist facies, eclogite fades or epidote-amphibolite facies and ending up with the greenschist facies. The incremental Ar-Ar dating shows that the plateau ages for the high-pressure rocks range from 410 to 443 Ma. The plateau ages could be used as a minimum age constraint for the subduction that resulted in the formation of these high-pressure rocks in the Qilian area. It is proposed that the late-stage decompressional and cooling P-T paths with ends at the greenschist facies for these high-pressure rocks probably reflect the uplift process which could occur after shifting the arc-trench tectonic system to the system of continental orogenic belts. The retrograde paths for the high-pressure rocks in the North Qilian tectonic belt are characterized by dramatic decompression with slight cooling, which suggests very rapid exhumation. Petrography supports that the mountain-building for the Qilian mountain range could undergo a very fast process which caused rapid uplift and denudation.展开更多
The high-pressure （HP） eclogite in the western Dabie Mountain encloses numerous hornblendes, mostly barroisite. Opinions on the peak metamorphic P-T condition, PT path and mineral paragenesis of it are still in disp...The high-pressure （HP） eclogite in the western Dabie Mountain encloses numerous hornblendes, mostly barroisite. Opinions on the peak metamorphic P-T condition, PT path and mineral paragenesis of it are still in dispute. Generally, HP eclogite involves garnet, omphacite, hornblendes and quartz, with or without glaucophane, zoisite and phengite. The garnet has compositional zoning with XMg increase, XCa and XMn decrease from core to rim, which indicates a progressive metamorphism. The phase equilibria of the HP eclogite modeled by the P-T pseudosection method developed recently showed the following： （1） the growth zonation of garnet records a progressive metamorphic PT path from pre-peak condition of 1.9-2.1 GPa at 508~C-514~C to a peak one of 2.3-2.5 GPa at 528~C-531~C for the HP eclogite; （2） the peak mineral assemblage is garnet＋omphacite＋glaucophane＋quartz_＋phengite, likely paragenetic with lawsonite; （3） the extensive hornblendes derive mainly from glaucophane, partial omphacite and even a little garnet due to the decompression with some heating during the post-peak stage, mostly representing the conditions of about 1.4-1.6 GPa and 580~C-640~C, and their growth is favored by the dehydration of lawsonite into zoisite or epidote, but most of the garnet, omphacite or phengite in the HP eclogite still preserve their compositions at peak condition, and they are not obviously equilibrious with the hornblendes.展开更多
In this paper we have studied the effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning vertical electric field and azimuthal magnetic field at different distances, by using two...In this paper we have studied the effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning vertical electric field and azimuthal magnetic field at different distances, by using two-dimensional finite-difference time-domain (2-D FDTD) method in cylindrical coordinate systems. In order to analyze the electrostatic shielding effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning, we chose three mountains, and the left one is stroke by lightning, and the right one is near the obervation site, and the middle one with the top heights increasing from 0 to 2 km is between them. For the observed point, the electrostatic shielding effect of the right one on the lightning vertical electric field is the most serious, and the electric field is much less than that for strike to flat ground level;compared with the electric field, the shielding effect of the right one on the lightning azimuthal magnetic field becomes less, for most cases, the lightning magnetic field at the observed site is larger than that for flat ground cases mainly due to that of the increment caused by strike to the right mountain. With the increase of distance (e.g., 20 km from the lightning strike point), the shielding effect of the right mountain on the lightning field becomes less, because the reflected wave from the right mountain bottom plays a more important role over intermediate ranges, and the far radiation electromagnetic field peak value becomes larger due to such a reflecting wave. Therefore, in the lightning detecting technique, we should pay more attention to the effect caused by chains of hills on the lightning location and the estimation of lightning current peak.展开更多
Evaporation controlled by meteorological parameters plays a crucial role in hydrology, meteorology and water resources management. An insight view of long-term variation in evaporation will help understanding the effe...Evaporation controlled by meteorological parameters plays a crucial role in hydrology, meteorology and water resources management. An insight view of long-term variation in evaporation will help understanding the effects of climate change and provide useful information for rational utilization of water resources, especially in the arid land where the shortage of water resources exists. However, the lack of data on evaporation led to difficulties in assessing the impacts of climate change on evaporation, especially in arid mountainous area. This study investigated the long-term variation of the pan-evaporation （Ep） measured by E601 type evaporation pan and its influencing climatic factors at both northern and southern slopes of the Tianshan Mountains in Xinjiang of China using the ensemble empirical mode decomposition method and Path analysis. The results revealed that Eps at both northern and southern slopes had obvious interdecadal variation within cycles of 3-4 and 7-8 years. Eps at both slopes sharply decreased in early 1980s, but increased after late 1990s. Path analysis showed that the 3-4 years cycle of Ep at the northern and southern slopes was mainly dependent upon actual water vapor pressure with a negative direct path coefficient of-0.515 and sunshine duration with a positive direct path coefficient of 0.370, respectively. The variation of Ep with cycle of 7-8 years at the northern slope was attributed to the wind speed with a direct path coefficient of 0.774. Average temperature had a direct path coefficient of 0.813 in 7-8 years cycle at the southern slope. The assessment of Ep variation and its causes provides information essential for a good understanding of hydrologic cycle and regional climate of arid mountainous regions in Xinjiang of China and offers a theoretical reference for distribution and utilization of water resources.展开更多
The process and path of retrometamorphism of coesite have great significance to our understanding of the P-T tracks of the exhumation of ultrahigh-pressure metamorphic rocks. Most of the coesites in the eclogite from ...The process and path of retrometamorphism of coesite have great significance to our understanding of the P-T tracks of the exhumation of ultrahigh-pressure metamorphic rocks. Most of the coesites in the eclogite from Shima, Anhui Province, the Dabie Mountains, China, are found degraded to quartz partly or wholly, with ruptures occurring in the shells, outside which include the coesite and quartz. According to the microscopic observation, the sample of coesite inclusion is composed of garnet, quartz and coesite, based on which we have built a three-shelled composite sphere model to compute the transition of coesite. Based on the crystal growth formulas and pressure conditions of the ruptures in the garnet, we have calculated the radius of the quartz sphere, which depends on temperature, and eventually drawn the different retrometamorphic paths for different retrometamorphism rates.展开更多
Eclogitic garnet-amphibole rocks are scattered around me Songshugou ultramafic bodies in Qinling Mountains . Three metamorphic stages are recognized in terms of petrography, mineral chemistry and geothermobarometry . ...Eclogitic garnet-amphibole rocks are scattered around me Songshugou ultramafic bodies in Qinling Mountains . Three metamorphic stages are recognized in terms of petrography, mineral chemistry and geothermobarometry . The first alhite-amphibole stage was of greenschist facies metamorphism with typical mineral assemblage of actinolite+epidote+chlorite+albite ; the pressure and temperature conditions were equal to or lower than 500MPa and about 400 ℃ .The second prograde eclogitic garnet-amphibole stage was of amphibole-eclogite fades metamorphism with typical mineral assemblage of garnet+hornblende± clinopyroxene+ruffle without ptagioclase ,the pressure condition was at least 1000- 1200MPa and the temperature about 600 ℃ .The third retrograde epidote-amphibole stage was of epidote-amphibolite fecies with assemblage of plagioclase+hornblende+epidote+ilmenite/titanite , the temperature was 500-600 ℃ and the pressure from 800MPa down to 500MPa .All three stages took place in one single tectonothermal event called Jinningian movement at about 1000Ma .The p-T path shows a hairpin shape and thus indicates a metamorphism in the sobduction environment. The metamorphk processes of the garnet- amphibole rocks thus provides a significant evidence for the pbte tectonic movement prevailing in the late Middle Proterozoic period.展开更多
Glacier shape factors （area, length, and thickness）, climatic factors （annual temperature and precipitation）, mass balance, and other influence factors, of the Qiyi glacier velocity and their intensity were analyz...Glacier shape factors （area, length, and thickness）, climatic factors （annual temperature and precipitation）, mass balance, and other influence factors, of the Qiyi glacier velocity and their intensity were analyzed with the application of the path analysis method during 1958-2007. Results indicate that glacier velocity was mainly influenced by glacier shape, followed by mass balance and climatic conditions. Among the influence factors, glacier area and thickness are most significant, and direct and indirect path coef- ficients are respectively 6.56, 4.71, 19.29 and 13.57. This research provides information for further understanding glacier velocity and its influencing factors.展开更多
基金Sponsored by Key Research Projects in Humanities and Social Sciences of Hubei Provincial Department of Education(15D115)Technology Innovation Team Projects for Outstanding Young and Middle-Aged Scholars of Hubei Provincial Department of Education(Q20162907)
文摘Relying on rich tourism resources of the Dabie Mountains to accelerate industrialized poverty alleviation and development is the inevitable choice of promoting regional economic and social leapfrog development. The realistic basis of pro-poor tourism of the Dabie Mountains is already ready and continuously strengthened. This paper, based on domestic and foreign pro-poor tourism practices, put forward the development path to pro-poor-tourism of Dabie Mountains of "establishing tourism development platform with the government as the leading factor; establishing the benefit sharing mechanism of pro-poor tourism with community participation as the main line; improving the community residents' professionalism in engaging in tourism with local residents as the main body; enhancing the overall effectiveness of pro-poor tourism with tourism as the principal industry".
文摘Petrologic geochemistry and isotopic chronology of the eclogites sug ge st that most of the eclogites in northern Dabie Mountains produced from the Tria ssic Yangtze subducted continental crust (lower crust and formed during the deep subduction) and the metamorphosed mafic untramafic belt with eclogite, marble and meta peridotite blocks around the Mozitan Xiaotian fault zone may represen t the meta tectonic melange produced during the active subduction of an ancient oceanic slab and subsequent collision between the Yangtze and North China conti nental plates. The cooling history of the eclogites from ～900 ℃ to 300 ℃ can b e subdivided into three stages: one isothermal stage and two rapid cooling stage s. The initial stage between (230±6) and 210 Ma was a near isothermal or tempe rature rise process corresponding to the retrograded metamorphism of granulite facies with a rapid uplift of 4 mm/a, then two fast cooling stages occurred with cooling rate of ～10 ℃/Ma during 210 Ma to (172±3) Ma and ～4 ℃/Ma durin g (172±3) Ma to 130 Ma. After the peak metamorphism of eclogite facies, their in itial isothermal stage with slower uplift rate and cooling rate and high T overprinting of granulite facies metamorphism is the major difference between t he eclogites in northern Dabie Mountains from those in southern Dabie Mountains. This may be one of the most important reasons to preserve few evidences of earl ier ultrahigh pressure metamorphism.
文摘After the integration of petrographic study, geothermobarometry and Gibbs method, the synthetic P-T paths for the rocks from different geological profiles in the North Qilian, China, have been derived. The composite P-T paths from different methods indicate that all the high-pressure rocks in the Qilian area recorded P-T paths with clockwise loops starting at the blueschist facies, later reaching peak metamorphism at the blueschist facies, eclogite fades or epidote-amphibolite facies and ending up with the greenschist facies. The incremental Ar-Ar dating shows that the plateau ages for the high-pressure rocks range from 410 to 443 Ma. The plateau ages could be used as a minimum age constraint for the subduction that resulted in the formation of these high-pressure rocks in the Qilian area. It is proposed that the late-stage decompressional and cooling P-T paths with ends at the greenschist facies for these high-pressure rocks probably reflect the uplift process which could occur after shifting the arc-trench tectonic system to the system of continental orogenic belts. The retrograde paths for the high-pressure rocks in the North Qilian tectonic belt are characterized by dramatic decompression with slight cooling, which suggests very rapid exhumation. Petrography supports that the mountain-building for the Qilian mountain range could undergo a very fast process which caused rapid uplift and denudation.
基金funded by the National Natural Science Foundation of China (No.40525006 and 40372032).
文摘The high-pressure （HP） eclogite in the western Dabie Mountain encloses numerous hornblendes, mostly barroisite. Opinions on the peak metamorphic P-T condition, PT path and mineral paragenesis of it are still in dispute. Generally, HP eclogite involves garnet, omphacite, hornblendes and quartz, with or without glaucophane, zoisite and phengite. The garnet has compositional zoning with XMg increase, XCa and XMn decrease from core to rim, which indicates a progressive metamorphism. The phase equilibria of the HP eclogite modeled by the P-T pseudosection method developed recently showed the following： （1） the growth zonation of garnet records a progressive metamorphic PT path from pre-peak condition of 1.9-2.1 GPa at 508~C-514~C to a peak one of 2.3-2.5 GPa at 528~C-531~C for the HP eclogite; （2） the peak mineral assemblage is garnet＋omphacite＋glaucophane＋quartz_＋phengite, likely paragenetic with lawsonite; （3） the extensive hornblendes derive mainly from glaucophane, partial omphacite and even a little garnet due to the decompression with some heating during the post-peak stage, mostly representing the conditions of about 1.4-1.6 GPa and 580~C-640~C, and their growth is favored by the dehydration of lawsonite into zoisite or epidote, but most of the garnet, omphacite or phengite in the HP eclogite still preserve their compositions at peak condition, and they are not obviously equilibrious with the hornblendes.
文摘In this paper we have studied the effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning vertical electric field and azimuthal magnetic field at different distances, by using two-dimensional finite-difference time-domain (2-D FDTD) method in cylindrical coordinate systems. In order to analyze the electrostatic shielding effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning, we chose three mountains, and the left one is stroke by lightning, and the right one is near the obervation site, and the middle one with the top heights increasing from 0 to 2 km is between them. For the observed point, the electrostatic shielding effect of the right one on the lightning vertical electric field is the most serious, and the electric field is much less than that for strike to flat ground level;compared with the electric field, the shielding effect of the right one on the lightning azimuthal magnetic field becomes less, for most cases, the lightning magnetic field at the observed site is larger than that for flat ground cases mainly due to that of the increment caused by strike to the right mountain. With the increase of distance (e.g., 20 km from the lightning strike point), the shielding effect of the right mountain on the lightning field becomes less, because the reflected wave from the right mountain bottom plays a more important role over intermediate ranges, and the far radiation electromagnetic field peak value becomes larger due to such a reflecting wave. Therefore, in the lightning detecting technique, we should pay more attention to the effect caused by chains of hills on the lightning location and the estimation of lightning current peak.
基金funded by the National Basic Research Program of China(2012CB956204)the Special Funds for Key Laboratories of the Xinjiang Uygur Autonomous Region(2014KL015)
文摘Evaporation controlled by meteorological parameters plays a crucial role in hydrology, meteorology and water resources management. An insight view of long-term variation in evaporation will help understanding the effects of climate change and provide useful information for rational utilization of water resources, especially in the arid land where the shortage of water resources exists. However, the lack of data on evaporation led to difficulties in assessing the impacts of climate change on evaporation, especially in arid mountainous area. This study investigated the long-term variation of the pan-evaporation （Ep） measured by E601 type evaporation pan and its influencing climatic factors at both northern and southern slopes of the Tianshan Mountains in Xinjiang of China using the ensemble empirical mode decomposition method and Path analysis. The results revealed that Eps at both northern and southern slopes had obvious interdecadal variation within cycles of 3-4 and 7-8 years. Eps at both slopes sharply decreased in early 1980s, but increased after late 1990s. Path analysis showed that the 3-4 years cycle of Ep at the northern and southern slopes was mainly dependent upon actual water vapor pressure with a negative direct path coefficient of-0.515 and sunshine duration with a positive direct path coefficient of 0.370, respectively. The variation of Ep with cycle of 7-8 years at the northern slope was attributed to the wind speed with a direct path coefficient of 0.774. Average temperature had a direct path coefficient of 0.813 in 7-8 years cycle at the southern slope. The assessment of Ep variation and its causes provides information essential for a good understanding of hydrologic cycle and regional climate of arid mountainous regions in Xinjiang of China and offers a theoretical reference for distribution and utilization of water resources.
基金the National Natural Science Foundation of China grants 40172019 ,40272083 the Natural Science Foundation of HubeiProvince grant 2002AB020.
文摘The process and path of retrometamorphism of coesite have great significance to our understanding of the P-T tracks of the exhumation of ultrahigh-pressure metamorphic rocks. Most of the coesites in the eclogite from Shima, Anhui Province, the Dabie Mountains, China, are found degraded to quartz partly or wholly, with ruptures occurring in the shells, outside which include the coesite and quartz. According to the microscopic observation, the sample of coesite inclusion is composed of garnet, quartz and coesite, based on which we have built a three-shelled composite sphere model to compute the transition of coesite. Based on the crystal growth formulas and pressure conditions of the ruptures in the garnet, we have calculated the radius of the quartz sphere, which depends on temperature, and eventually drawn the different retrometamorphic paths for different retrometamorphism rates.
基金The project is supported by National Nature Science Fountation of China No.48900015
文摘Eclogitic garnet-amphibole rocks are scattered around me Songshugou ultramafic bodies in Qinling Mountains . Three metamorphic stages are recognized in terms of petrography, mineral chemistry and geothermobarometry . The first alhite-amphibole stage was of greenschist facies metamorphism with typical mineral assemblage of actinolite+epidote+chlorite+albite ; the pressure and temperature conditions were equal to or lower than 500MPa and about 400 ℃ .The second prograde eclogitic garnet-amphibole stage was of amphibole-eclogite fades metamorphism with typical mineral assemblage of garnet+hornblende± clinopyroxene+ruffle without ptagioclase ,the pressure condition was at least 1000- 1200MPa and the temperature about 600 ℃ .The third retrograde epidote-amphibole stage was of epidote-amphibolite fecies with assemblage of plagioclase+hornblende+epidote+ilmenite/titanite , the temperature was 500-600 ℃ and the pressure from 800MPa down to 500MPa .All three stages took place in one single tectonothermal event called Jinningian movement at about 1000Ma .The p-T path shows a hairpin shape and thus indicates a metamorphism in the sobduction environment. The metamorphk processes of the garnet- amphibole rocks thus provides a significant evidence for the pbte tectonic movement prevailing in the late Middle Proterozoic period.
基金supported by the Global Change Research Program of China (2010CB951404)The National Natura Science Foundation of China (41071043)
文摘Glacier shape factors （area, length, and thickness）, climatic factors （annual temperature and precipitation）, mass balance, and other influence factors, of the Qiyi glacier velocity and their intensity were analyzed with the application of the path analysis method during 1958-2007. Results indicate that glacier velocity was mainly influenced by glacier shape, followed by mass balance and climatic conditions. Among the influence factors, glacier area and thickness are most significant, and direct and indirect path coef- ficients are respectively 6.56, 4.71, 19.29 and 13.57. This research provides information for further understanding glacier velocity and its influencing factors.
