Mountain water, which contributes 50% to 90% to the lower reaches of the watershed, has a considerably low utility efficiency. The water accessibility could be a quantitative measure of water scarcity in the mountains...Mountain water, which contributes 50% to 90% to the lower reaches of the watershed, has a considerably low utility efficiency. The water accessibility could be a quantitative measure of water scarcity in the mountains. It can be used effectively for emergency water shortage planning and water resource management. In the present study, Dongchuan District, a typical county in the Hengduan Mountains in Yunnan province of Southwest China, was selected as the study area, and the minimal cumulative resistance(MCR) model was used to simulate the least-cost path(LCP) from 1255 point features of natural villages, as well as 12,368 dryfield centroids, to their respective surrounding river systems, which serve as a source for emergency drinking water and irrigation during droughts. The average length of the LCP for each administrative village was calculated to represent the accessibility to water sources for agricultural production and daily life in these mountain villages. The distribution of population and dryfields, as well as other geographic elements, were analyzed to classify the degree of water scarcity in these villages. The results indicate that the area facing the highest risk of water shortage for agricultural irrigation is located in northern Dongchuan, in particular along the two sides of the Xiaojiang Valley, and that the area with the highest risk of water shortage for daily life needs is located along the Xiaojiang Valley.展开更多
Mafic intrusions and dykes are well preserved in the Yinmin and Lanniping districts, located within the western margin of the Yangtze Block, SW China. Although these mafic rocks from the two areas formed during differ...Mafic intrusions and dykes are well preserved in the Yinmin and Lanniping districts, located within the western margin of the Yangtze Block, SW China. Although these mafic rocks from the two areas formed during different periods, they share similar ranges of PGE concentration. Most of the Yinmin gabbroic dykes contain relatively high PGE concentrations （PGEs=13.9-87.0 ppb） and low S contents （0.003 %-0.020 %）, higher than the maximum PGE concentrations of mafic magmas melting from the mantle. Two exceptional Yinmin samples are characterized by relatively low PGE （PGEs = 0.31-0.37 ppb）and high S （0.114 %-0.257 %） contents. In contrast, most samples from the Lanniping gabbroic intrusion have low PGE con- centrations （PGEs = 0.12-1.02 ppb） and high S contents （0.130 %-0.360 %）, except that the three samples exhibit relatively high PGE （PGEs=16.3-34.8 ppb） and low S concentrations （0.014 %-0.070 %）. All the Yinmin and Lanniping samples are characterized by the enrichment of PPGE relative to IPGE in the primitive-mantle normalized diagrams, and the high-PGE samples exhibit obvious Ru anomalies. This study suggests that during the ascent of the parental magma, removal of Os-Ir-Ru alloys and/or chro- mite/spinel leads to high Pd/Ir ratios and Ru anomalies for the Yinmin high-PGE samples and relatively lower Pd/lr ratios and Ru anomalies for the Lanniping low-PGE samples. We propose that the magmas parental to the Yinmin gabbroic dykes are initially S-unsaturated, and subsequently, minor evolved magma reached sulfur saturation and led to sulfide segregation. Although the Lanniping parental magmas are originally not saturated in S, the high Cu/Pd ratios （3.8× 10^4 to 3.2 × 10^6） for most of the Lanniping samples indicate the S-saturated state and sulfide segregation. A calculation shows that the PGE-poor magmas might have experienced 0.01%-0.1%sulfidesegregationinthemagma chamber. Therefore, our study provides a possible opportunity to discover PGE-enriched sulfide mineralization some- where near or within the Lanniping mafic intrusion.展开更多
On the southwestern margin of the Yangtze Block, the Dongchuan Group consists of slightly metamorphosed sedimentary rocks, including silty slate, argillaceous slate, clayey slate, arkose, dolomite, and minor volcanic ...On the southwestern margin of the Yangtze Block, the Dongchuan Group consists of slightly metamorphosed sedimentary rocks, including silty slate, argillaceous slate, clayey slate, arkose, dolomite, and minor volcanic rocks. To date, it is still a controversy over the depositional age and stratigraphic sequence of the Dongchuan Group. In this study, we analyzed five samples of meta-sedimentary rocks and one sample of meta-tuff from the Yinmin, Luoxue and Etouchang Formations of the Dongchuan Group in the Yuxi region for detrital zircon U-Pb ages and Lu-Hf isotope. The detrital zircon ages of the meta-sediments vary from 3073 to 1703 Ma, mainly clustered at three periods, from 1889 to 1840, 2490 to 2008 and 2878 to 2844 Ma. The youngest age peak of all the samples is ~1859 Ma, with the εHf(t) values of the zircons ranging from-20.3 to +4.3 and more than 90% being negative, indicating that the Paleoproterozoic crustal accretion on the southwestern margin of the Yangtze Block was dominated by reworking of the ancient crustal materials involved in the assembly and breakup of the Columbia supercontinent. Another important age range is between 2490 Ma and 2008 Ma, with εHf(t) values from-14.7 to +8.9 and 70% of them are negative, suggesting that the magmatism in the source area was also dominated by reworking and recycling of the ancient crustal materials, with minor juvenile mantle substances added. The detritus was probably derived from the Paleoproterozoic crystalline basement in the southern Yuxi region. The oldest peak age is ~2847 Ma and the εHf(t) values are from-7.7 to +7.0 with 50% of both positive and negative values, demonstrating a possible ~2.85 Ga ancient continental nucleus on the southwestern margin of the Yangtze Block and substantial growth in juvenile crust materials during this period. Besides, the weighted average age of the zircons from the meta-tuff of the Etouchang Formation is 1677 ± 14 Ma. Combining the previous research data and this study, we can constrain the depositional age of the Dongchuan Group in central Yunnan Province to the period from the late Paleoproterozoic to early Mesoproterozoic, slightly earlier than that of the Dongchuan Group in the Dongchuan area near to the southwestern Sichuan Province. The depositional age of the Dongchuan Group is older than that of the Kunyang Group.展开更多
Mafic"intrusive rocks",distributed greatly within Dongchuan strata-bound copperfield and really comprising volcanic,subvolcanic and volcano plutonic rocks,should be termed as volcanic-intrusive complex(VIC)....Mafic"intrusive rocks",distributed greatly within Dongchuan strata-bound copperfield and really comprising volcanic,subvolcanic and volcano plutonic rocks,should be termed as volcanic-intrusive complex(VIC).Geology and geochemistry of Jinningian VIC and its relation to Cu ores reaffirm that VIC play an important role in mineralizations,which are not only vein bonanzas deduced from coose beds,but also new orebodies occurred within VIC.Bonanzas of superposing-reworking type and orebodies of magmatic liquation-differentiation type in the depth are suggested to be found in the largely developing VIC area.展开更多
Ecology-oriented poverty alleviation is not only a livelihood project that affects the vast majority of rural people but also a major project to win the fight against poverty. It is also an indispensable income compon...Ecology-oriented poverty alleviation is not only a livelihood project that affects the vast majority of rural people but also a major project to win the fight against poverty. It is also an indispensable income component for the relocation of poor farmers. Dongchuan District,located at the intersection of Jinsha River and Xiaojiang River,is one of the key counties for poverty alleviation and development in China with a wide range of poverty and extreme poverty. The incidence of poverty reached 24. 36%. The ecology is fragile,and earthquake outbreaks frequently. Dongchuan District is a national key monitoring and defense area for earthquakes. A large number of goafs,subsidence areas and geological hazard areas have been formed in the mining area. The number of dangerous houses is large,and ' it has no way of supporting its own inhabitants' is the key point,difficulty and focus of the county’s poverty alleviation. Relocation is a must-have measure to move away from poverty. It is also complex system engineering,which is policy-oriented and difficult. Since 2017,Dongchuan District has regarded relocation has the top priority for poverty alleviation. It has strictly implemented national,provincial and municipal policies,focused on the overall goal of ' moving,securing and getting rich',and strongly promoted the relocation work for poverty alleviation. Obvious social,economic and ecological benefits have been achieved. Successful relocation,combined with ecology-oriented poverty alleviation and other targeted poverty alleviation measures,Dongchuan District’s fight against poverty has achieved a decisive victory. At the end of December 2018,the incidence of poverty in the region fell to 1. 09%,and 129 poor villages( including 86 extremely poor villages) had been successfully lifted out of poverty. This paper analyzes and condenses the specific practices,main achievements,benefits,successful experiences and implications of the region’s relocation combined with ecology-oriented poverty alleviation model,so as to provide necessary reference for the innovation of relocation in poverty-stricken counties of Yunnan Province and similar provinces( cities,districts).展开更多
Poverty alleviation through employment promotion is to promote the poor households to get rid of poverty through promoting employment to increase income. It is the most effective and direct way out of poverty. Dongchu...Poverty alleviation through employment promotion is to promote the poor households to get rid of poverty through promoting employment to increase income. It is the most effective and direct way out of poverty. Dongchuan District, located in the alpine valley area of northeastern Yunnan, is a typical extreme poverty-stricken county in China. Under its jurisdiction, Awang Town is a mountainous township with a wide area of poverty and an extreme poverty. The incidence of poverty in 2015 reached 35.39%. In recent years, through the implementation of various policies to combat poverty, combined with the advantages as a traditional "hometown of migrant labor", focusing on employment- promoting poverty alleviation work, Awang Town has made certain achievements in poverty alleviation work. By the end of 2018, the poverty rate in the town fell to 0.57%, marking a major victory in the town s fight against poverty. Through field investigations, this article summarizes the main practices of Awang Town to carry out employment-promoting targeted poverty alleviation, analyzes the poverty alleviation achievements and successful experience of the town s employment-promoting targeted poverty alleviation work and discusses the promotion and application of this model so as to provide reference Yunnan Province and other poverty-stricken areas to carry out employment-promoting poverty alleviation.展开更多
Dongchuan District of Kunming City has undulating terrain with large fluctuations, fragile ecological environment, low rainfall and high evaporation, coupled with frequent debris flow activities, resulting in very low...Dongchuan District of Kunming City has undulating terrain with large fluctuations, fragile ecological environment, low rainfall and high evaporation, coupled with frequent debris flow activities, resulting in very low forest coverage rate in Dongchuan. In this study, a comprehensive and systematic investigation was carried out to the green planting of barren hills in Dongchuan District from January to June, 2016. The results showed that the major planting tree species in the region with an altitude of less than 1 600 m were Leucaena leucocephala, Cupressus torulosa, L. leucocephala, C. torulosa, Celtis yunnanensis, Melia azedarach , among which L. leucocephala had become of pioneer tree species of afforestation in the Dongchuan dry-hot valley. The major planting tree species at the altitude of 1 600-2 500 m were C. torulosa, Sabina chinensis, Alnus nepalensis, C. yunnanensis, and Pinus armandi , and at the altitude of over 2 500 m, the major tree species were Sabina chinensis, Abies georgei var. smithii, P.densata. Based on the investigation, suggestions were proposed for the existing problems in the greening and planting of Dongchuan barren hills, in order to provide certain theoretical basis for the sustainable development of forestry in Dongchuan.展开更多
In this paper the Pb-Pb isochron method was used to determine the isotopic ages of the Luoxue Formation dolomites (1716±56 Ma), the Heishan Formation carbonaceous slates (1607±128 Ma) of the middle sub-group...In this paper the Pb-Pb isochron method was used to determine the isotopic ages of the Luoxue Formation dolomites (1716±56 Ma), the Heishan Formation carbonaceous slates (1607±128 Ma) of the middle sub-group of the Kunyang Group and the Dayingpan Formation carbonaceous slates (1258±70Ma) of the upper sub-group of the Kunyang Group. The age of the middle sub-group of the Kunyang Group is about 1800-1600 Ma, belonging to the Late Paleo-Proterozoic, and that of the Dayingpan Formation in the upper sub-group of the Kunyang Group is about 1200-1300 Ma, belonging to the Middle Proterozoic. In addition, the Pb isotope chemical exploration techniques were used to study systematically the Pb isotopic compositions of rocks and ores across the No.14 vein in the middle segment of the No.1 pit of the Tangdan copper deposit and the result showed that the Pb isotope V\-1 values are negatively correlated with the copper contents. It is the first trial to use the systematic section method to conduct Pb isotope chemical exploration.展开更多
基金financially supported by the National Program on Key Basic Research Project (973 Program) (Grant No. 2015CB452706)
文摘Mountain water, which contributes 50% to 90% to the lower reaches of the watershed, has a considerably low utility efficiency. The water accessibility could be a quantitative measure of water scarcity in the mountains. It can be used effectively for emergency water shortage planning and water resource management. In the present study, Dongchuan District, a typical county in the Hengduan Mountains in Yunnan province of Southwest China, was selected as the study area, and the minimal cumulative resistance(MCR) model was used to simulate the least-cost path(LCP) from 1255 point features of natural villages, as well as 12,368 dryfield centroids, to their respective surrounding river systems, which serve as a source for emergency drinking water and irrigation during droughts. The average length of the LCP for each administrative village was calculated to represent the accessibility to water sources for agricultural production and daily life in these mountain villages. The distribution of population and dryfields, as well as other geographic elements, were analyzed to classify the degree of water scarcity in these villages. The results indicate that the area facing the highest risk of water shortage for agricultural irrigation is located in northern Dongchuan, in particular along the two sides of the Xiaojiang Valley, and that the area with the highest risk of water shortage for daily life needs is located along the Xiaojiang Valley.
基金supported by the National Natural Science Foundation of China(41425011 and 41303016)
文摘Mafic intrusions and dykes are well preserved in the Yinmin and Lanniping districts, located within the western margin of the Yangtze Block, SW China. Although these mafic rocks from the two areas formed during different periods, they share similar ranges of PGE concentration. Most of the Yinmin gabbroic dykes contain relatively high PGE concentrations （PGEs=13.9-87.0 ppb） and low S contents （0.003 %-0.020 %）, higher than the maximum PGE concentrations of mafic magmas melting from the mantle. Two exceptional Yinmin samples are characterized by relatively low PGE （PGEs = 0.31-0.37 ppb）and high S （0.114 %-0.257 %） contents. In contrast, most samples from the Lanniping gabbroic intrusion have low PGE con- centrations （PGEs = 0.12-1.02 ppb） and high S contents （0.130 %-0.360 %）, except that the three samples exhibit relatively high PGE （PGEs=16.3-34.8 ppb） and low S concentrations （0.014 %-0.070 %）. All the Yinmin and Lanniping samples are characterized by the enrichment of PPGE relative to IPGE in the primitive-mantle normalized diagrams, and the high-PGE samples exhibit obvious Ru anomalies. This study suggests that during the ascent of the parental magma, removal of Os-Ir-Ru alloys and/or chro- mite/spinel leads to high Pd/Ir ratios and Ru anomalies for the Yinmin high-PGE samples and relatively lower Pd/lr ratios and Ru anomalies for the Lanniping low-PGE samples. We propose that the magmas parental to the Yinmin gabbroic dykes are initially S-unsaturated, and subsequently, minor evolved magma reached sulfur saturation and led to sulfide segregation. Although the Lanniping parental magmas are originally not saturated in S, the high Cu/Pd ratios （3.8× 10^4 to 3.2 × 10^6） for most of the Lanniping samples indicate the S-saturated state and sulfide segregation. A calculation shows that the PGE-poor magmas might have experienced 0.01%-0.1%sulfidesegregationinthemagma chamber. Therefore, our study provides a possible opportunity to discover PGE-enriched sulfide mineralization some- where near or within the Lanniping mafic intrusion.
基金financially supported by the Geological Survey Project of the China Geological Survey(DD20190370)。
文摘On the southwestern margin of the Yangtze Block, the Dongchuan Group consists of slightly metamorphosed sedimentary rocks, including silty slate, argillaceous slate, clayey slate, arkose, dolomite, and minor volcanic rocks. To date, it is still a controversy over the depositional age and stratigraphic sequence of the Dongchuan Group. In this study, we analyzed five samples of meta-sedimentary rocks and one sample of meta-tuff from the Yinmin, Luoxue and Etouchang Formations of the Dongchuan Group in the Yuxi region for detrital zircon U-Pb ages and Lu-Hf isotope. The detrital zircon ages of the meta-sediments vary from 3073 to 1703 Ma, mainly clustered at three periods, from 1889 to 1840, 2490 to 2008 and 2878 to 2844 Ma. The youngest age peak of all the samples is ~1859 Ma, with the εHf(t) values of the zircons ranging from-20.3 to +4.3 and more than 90% being negative, indicating that the Paleoproterozoic crustal accretion on the southwestern margin of the Yangtze Block was dominated by reworking of the ancient crustal materials involved in the assembly and breakup of the Columbia supercontinent. Another important age range is between 2490 Ma and 2008 Ma, with εHf(t) values from-14.7 to +8.9 and 70% of them are negative, suggesting that the magmatism in the source area was also dominated by reworking and recycling of the ancient crustal materials, with minor juvenile mantle substances added. The detritus was probably derived from the Paleoproterozoic crystalline basement in the southern Yuxi region. The oldest peak age is ~2847 Ma and the εHf(t) values are from-7.7 to +7.0 with 50% of both positive and negative values, demonstrating a possible ~2.85 Ga ancient continental nucleus on the southwestern margin of the Yangtze Block and substantial growth in juvenile crust materials during this period. Besides, the weighted average age of the zircons from the meta-tuff of the Etouchang Formation is 1677 ± 14 Ma. Combining the previous research data and this study, we can constrain the depositional age of the Dongchuan Group in central Yunnan Province to the period from the late Paleoproterozoic to early Mesoproterozoic, slightly earlier than that of the Dongchuan Group in the Dongchuan area near to the southwestern Sichuan Province. The depositional age of the Dongchuan Group is older than that of the Kunyang Group.
基金One part of the Nationar"Eight-Five"Key Science and Technology Program(85-901-04-04)。
文摘Mafic"intrusive rocks",distributed greatly within Dongchuan strata-bound copperfield and really comprising volcanic,subvolcanic and volcano plutonic rocks,should be termed as volcanic-intrusive complex(VIC).Geology and geochemistry of Jinningian VIC and its relation to Cu ores reaffirm that VIC play an important role in mineralizations,which are not only vein bonanzas deduced from coose beds,but also new orebodies occurred within VIC.Bonanzas of superposing-reworking type and orebodies of magmatic liquation-differentiation type in the depth are suggested to be found in the largely developing VIC area.
基金Supported by Commissioned Project of Office of Rural Work Leading Group of Kunming Municipal Committee of the Communist Party of China"Study on the Poverty Alleviation Model of Kunming City in the Context of World Poverty Reduction"
文摘Ecology-oriented poverty alleviation is not only a livelihood project that affects the vast majority of rural people but also a major project to win the fight against poverty. It is also an indispensable income component for the relocation of poor farmers. Dongchuan District,located at the intersection of Jinsha River and Xiaojiang River,is one of the key counties for poverty alleviation and development in China with a wide range of poverty and extreme poverty. The incidence of poverty reached 24. 36%. The ecology is fragile,and earthquake outbreaks frequently. Dongchuan District is a national key monitoring and defense area for earthquakes. A large number of goafs,subsidence areas and geological hazard areas have been formed in the mining area. The number of dangerous houses is large,and ' it has no way of supporting its own inhabitants' is the key point,difficulty and focus of the county’s poverty alleviation. Relocation is a must-have measure to move away from poverty. It is also complex system engineering,which is policy-oriented and difficult. Since 2017,Dongchuan District has regarded relocation has the top priority for poverty alleviation. It has strictly implemented national,provincial and municipal policies,focused on the overall goal of ' moving,securing and getting rich',and strongly promoted the relocation work for poverty alleviation. Obvious social,economic and ecological benefits have been achieved. Successful relocation,combined with ecology-oriented poverty alleviation and other targeted poverty alleviation measures,Dongchuan District’s fight against poverty has achieved a decisive victory. At the end of December 2018,the incidence of poverty in the region fell to 1. 09%,and 129 poor villages( including 86 extremely poor villages) had been successfully lifted out of poverty. This paper analyzes and condenses the specific practices,main achievements,benefits,successful experiences and implications of the region’s relocation combined with ecology-oriented poverty alleviation model,so as to provide necessary reference for the innovation of relocation in poverty-stricken counties of Yunnan Province and similar provinces( cities,districts).
基金Supported by Construction Project of Party Branch Secretary’s Studio of "Double Leader" Teachers in Colleges and Universities of the Ministry of Education of ChinaProject of Party Construction Research of Yunnan University of Finance and Economics
文摘Poverty alleviation through employment promotion is to promote the poor households to get rid of poverty through promoting employment to increase income. It is the most effective and direct way out of poverty. Dongchuan District, located in the alpine valley area of northeastern Yunnan, is a typical extreme poverty-stricken county in China. Under its jurisdiction, Awang Town is a mountainous township with a wide area of poverty and an extreme poverty. The incidence of poverty in 2015 reached 35.39%. In recent years, through the implementation of various policies to combat poverty, combined with the advantages as a traditional "hometown of migrant labor", focusing on employment- promoting poverty alleviation work, Awang Town has made certain achievements in poverty alleviation work. By the end of 2018, the poverty rate in the town fell to 0.57%, marking a major victory in the town s fight against poverty. Through field investigations, this article summarizes the main practices of Awang Town to carry out employment-promoting targeted poverty alleviation, analyzes the poverty alleviation achievements and successful experience of the town s employment-promoting targeted poverty alleviation work and discusses the promotion and application of this model so as to provide reference Yunnan Province and other poverty-stricken areas to carry out employment-promoting poverty alleviation.
基金Supported by the Forestry Science and Technology Innovation Project of Yunnan([2014]CX05)
文摘Dongchuan District of Kunming City has undulating terrain with large fluctuations, fragile ecological environment, low rainfall and high evaporation, coupled with frequent debris flow activities, resulting in very low forest coverage rate in Dongchuan. In this study, a comprehensive and systematic investigation was carried out to the green planting of barren hills in Dongchuan District from January to June, 2016. The results showed that the major planting tree species in the region with an altitude of less than 1 600 m were Leucaena leucocephala, Cupressus torulosa, L. leucocephala, C. torulosa, Celtis yunnanensis, Melia azedarach , among which L. leucocephala had become of pioneer tree species of afforestation in the Dongchuan dry-hot valley. The major planting tree species at the altitude of 1 600-2 500 m were C. torulosa, Sabina chinensis, Alnus nepalensis, C. yunnanensis, and Pinus armandi , and at the altitude of over 2 500 m, the major tree species were Sabina chinensis, Abies georgei var. smithii, P.densata. Based on the investigation, suggestions were proposed for the existing problems in the greening and planting of Dongchuan barren hills, in order to provide certain theoretical basis for the sustainable development of forestry in Dongchuan.
文摘In this paper the Pb-Pb isochron method was used to determine the isotopic ages of the Luoxue Formation dolomites (1716±56 Ma), the Heishan Formation carbonaceous slates (1607±128 Ma) of the middle sub-group of the Kunyang Group and the Dayingpan Formation carbonaceous slates (1258±70Ma) of the upper sub-group of the Kunyang Group. The age of the middle sub-group of the Kunyang Group is about 1800-1600 Ma, belonging to the Late Paleo-Proterozoic, and that of the Dayingpan Formation in the upper sub-group of the Kunyang Group is about 1200-1300 Ma, belonging to the Middle Proterozoic. In addition, the Pb isotope chemical exploration techniques were used to study systematically the Pb isotopic compositions of rocks and ores across the No.14 vein in the middle segment of the No.1 pit of the Tangdan copper deposit and the result showed that the Pb isotope V\-1 values are negatively correlated with the copper contents. It is the first trial to use the systematic section method to conduct Pb isotope chemical exploration.
