The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of ...The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of Jiangsu. 14 metals, including Zn, Cu, Pb, Cd, Cr, Ni, Mo, Mn, Ba, Co, Sr, Ti, As and Hg, were analyzed after samples acid digestion. The results showed that the most feed samples contained high concentration of metals exceeding National Hygienical Standard for Feeds. Meanwhile, it was found that Cu, Zn, Pb, Cd and Cr concentrations in animal manures were also high, for example, Cu concentration in a manure sample reached to as much as 1726 3 mg/kg. Heavy metals loading quantities in soil per year were then calculated when metals contaminated organic fertilizers were applied, and its effects on soil environmental quality were further evaluated.展开更多
Background:The 2019 novel coronavirus(2019-nCoV)causing an outbreak of pneumonia in Wuhan,Hubei province of China was isolated in January 2020.This study aims to investigate its epidemiologic history,and analyze the c...Background:The 2019 novel coronavirus(2019-nCoV)causing an outbreak of pneumonia in Wuhan,Hubei province of China was isolated in January 2020.This study aims to investigate its epidemiologic history,and analyze the clinical characteristics,treatment regimens,and prognosis of patients infected with 2019-nCoV during this outbreak.Methods:Clinical data from 1372019-nCoV-infected patients admitted to the respiratory departments of nine tertiary hospitals in Hubei province from December 30,2019 to January 24,2020 were retrospectively collected,including general status,clinical manifestations,laboratory test results,imaging characteristics,and treatment regimens.Results:None of the 137 patients(61 males,76 females,aged 20-83 years,median age 57 years)had a definite history of exposure to Huanan Seafood Wholesale Market.Major initial symptoms included fever(112/137,81.8%),coughing(66/137,48.2%),and muscle pain or fatigue(44/137,32.1%),with other,less typical initial symptoms observed at low frequency,including heart palpitations,diarrhea,and headache.Nearly 80%of the patients had normal or decreased white blood cell counts,and 72.3%(99/137)had lymphocytopenia.Lung involvement was present in all cases,with most chest computed tomography scans showing lesions in multiple lung lobes,some of which were dense;ground-glass opacity co-existed with consolidation shadows or cord-like shadows.Given the lack of effective drugs,treatment focused on symptomatic and respiratory support.Immunoglobulin G was delivered to some critically ill patients according to their conditions.Systemic corticosteroid treatment did not show significant benefits.Notably,early respiratory support facilitated disease recovery and improved prognosis.The risk of death was primarily associated with age,underlying chronic diseases,and median interval from the appearance of initial symptoms to dyspnea.Conclusions:The majority of patients with 2019-nCoV pneumonia present with fever as the first symptom,and most of them still showed typical manifestations of v展开更多
By using the SHRIMP U-Pb and single zircon stepwise evaporation methods, the authors have obtained some results for granitoids from eastern Hebei Province. The Yuhuzhai hyperthene tonalitic granite was formed 2550 Ma ...By using the SHRIMP U-Pb and single zircon stepwise evaporation methods, the authors have obtained some results for granitoids from eastern Hebei Province. The Yuhuzhai hyperthene tonalitic granite was formed 2550 Ma ago, the Qingyangshu gabbroic gneiss 2536 Ma, the Yinmahe granodioritic gneiss near Lücao, Lulong County, 2533 Ma, the gabbro-dioritic gneiss near Longwan, Qianxi County, 2518-2515 Ma, the Qiuhuayu trondjemitic gneiss at Zunhua 2515 Ma, the Xiaoguanzhuang tonalitic gneiss at Zunhua 2495 Ma, and the Cuizhangzi gneiss in Qianxi County 2492 Ma. These geochronilogical data demonstrate that, though diverse in composition, type and origin, the granitic gneisses in eastern Hebei Province were emplaced and crystallized in a rather short period of magmatic activity. The formation of such a great amount of gneisses in this small time gap suggests that it was a critical crust accretion stage at the end of Neoarchean. The fact that granitoids of various types occurred at the same time implies a large-scale underplating （mantle plume） activity, which was then responsible for the crust accretion.展开更多
The fall armyworm(FAW),Spodoptera frugiperda is one of the most damaging crop pests,and it has become major threat to the food security of many countries.In order to monitor possible invasion of this pest into China,a...The fall armyworm(FAW),Spodoptera frugiperda is one of the most damaging crop pests,and it has become major threat to the food security of many countries.In order to monitor possible invasion of this pest into China,a searchlight trap was established in March 2018 in western Yunnan Province,China,where it has served as the"first station"for many pests that have migrated from Myanmar to China.A number of suspected FAW moths were captured and identified by DNA sequencing.The results showed that the FAW moth was first captured on December 11 and formed its first immigration peak in mid-December 2018.DNA detection revealed that the early invading FAW population was the"corn-strain".The field survey indicated that the pest mainly colonized corn in Pu’er,Dehong and Baoshan areas.Migration trajectory simulation implied that the moths might have mainly come from the eastern area in the mid-latitude region of Myanmar(20-25°N,94-100°E).This case study confirmed the first immigration of FAW into China,and will be helpful for guiding monitoring and management work to control this pest.展开更多
The late Permian Emeishan large igneous province （EL1P） covers -0.3× 10-6 kmL of the western margin of the Yangtze Block and Tibetan Plateau with displaced, correlative units in northern Vietnam （Song Da zone...The late Permian Emeishan large igneous province （EL1P） covers -0.3× 10-6 kmL of the western margin of the Yangtze Block and Tibetan Plateau with displaced, correlative units in northern Vietnam （Song Da zone）. The ELIP is of particular interest because it contains numerous world-class base metal deposits and is contemporaneous with the late Capitanian （-260 Ma） mass extinction. The flood basalts are the signature feature of the ELIP but there are also ultramafic and silicic volcanic rocks and layered mafic- ultramafic and silicic plutonic rocks exposed. The EL1P is divided into three nearly concentric zones （i.e. inner, middle and outer） which correspond to progressively thicker crust from the inner to the outer zone. The eruptive age of the ELIP is constrained by geological, paleomagnetic and geochronological evidence to an interval of 〈3 Ma. The presence of picritic rocks and thick piles of flood basalts testifies to high temperature thermal regime however there is uncertainty as to whether these magmas were derived from the subcontinental lithospheric mantle or sub-lithospheric mantle （i.e. asthenosphere or mantle plume） sources or both. The range of Sr （Isr ≈ 0.7040-0.7132）, Nd （ENd（t） ≈ -14 tO ＋8）, Pb （206-pb/204-pb1 ≈ 17.9-20.6） and Os （Yos ≈ -5 to ＋11） isotope values of the ultramafic and mafic rocks does not permit a conclusive answer to ultimate source origin of the primitive rocks but it is clear that some rocks were affected by crustal contamination and the presence of near-depleted isotope compo- sitions suggests that there is a sub-lithospheric mantle component in the system. The silicic rocks are derived by basaltic magmas/rocks through fractional crystallization or partial melting, crustal melting or by interactions between mafic and crustal melts. The formation of the Fe-Ti-V oxide-ore deposits is probably due to a combination of fractional crystallization of Ti-rich basalt and fluxing of C02-rich fluids whereas the Ni-Cu-（PGE） deposits a展开更多
The genesis of Indo-Sinian granitic plutons with peraluminous and potassium-rich affinities from Hunan Province, China has been investigated by numerical modeling using the numerical code FLAC. On the basis of the reg...The genesis of Indo-Sinian granitic plutons with peraluminous and potassium-rich affinities from Hunan Province, China has been investigated by numerical modeling using the numerical code FLAC. On the basis of the regional geological evolution in South China, we employed a realistic numerical model in an attempt to unravel the influences of basaltic underplating and tectonic crustal thickening on the crustal anatexis. Heat production derived from basaltic underplating (e.g. ca. 220 Ma gabbro xenoliths) can result in dehydration melting of fluid-bearing minerals in crustal rocks such as gneisses and metapelites, but its effect is limited in a relatively short time span (5-15 Ma) and on a small scale. Accordingly, it is very difficult for basaltic underplating to generate the large-scale Indo-Sinian granitic bathliths unless voluminous mafic magmas had been underplated at the lower/middle crust during this period. Alternatively, crustal thickening induced by tectonic compression can also lead to geothermal elevation, during which the temperature at the boundary between lower and middle crusts can be up to or greater than 700°C, triggering dehydration melting of muscovite in gneiss and metapelite. The proportion of melts from muscovite-induced dehydration melting is close to critical melt percentage (?20%) once the thickening factor reaches 1.3. These melts can be effectively transferred to the crust-level magma chamber and form large-scale granitic batholiths. In combination with the Indo-Sinian convergent tectonic setting in South China as well as sparse outcrops of contemporary mafic igneous rocks, we consider that tectonic crustal thickening is likely to be the predominant factor controlling the formation of the Indo-Sinian peraluminous and potassium-rich granitoids in Hunan Province.展开更多
The Xiangshan uranium ore field is the largest volcanic rock hosted uranium deposit in China.The host rock is a volcanic intrusive complex,including rhyodacite,porphyroclastic lava and late stage sub-volcanic rocks.In...The Xiangshan uranium ore field is the largest volcanic rock hosted uranium deposit in China.The host rock is a volcanic intrusive complex,including rhyodacite,porphyroclastic lava and late stage sub-volcanic rocks.In this study,zircons from an early stage rhyodacite and a late stage rhyodacite porphyry were dated by SHRIMP and LA-ICP-MS U-Pb methods,and their Hf isotopic compositions were measured by LA-MC-ICP-MS.206Pb/238U ages of 135.1±1.7 and 134.8±1.1 Ma were obtained for the rhyodacite and rhyodacitic porphyry,respectively.These accurate ages indicate that the Xiangshan volcanic-intrusive complex formed in the Early Cretaceous rather than in the Late Jurassic,as concluded in some previous studies.By the Early Cretaceous,the tectonic setting of the area has evolved into a back-arc extensional setting,possibly related to subduction of the paleo-Pacific plate.The close ages of the(early) eruptive rhyodacite and the(late) hypabyssal rhyodacitic porphyry shows that the Xiangshan volcanism was intensive and concentrated in a short time.Zircons from the rhyodacite show negative εHf(t) values of-5.7 to-8.5,with Hf depleted mantle model ages between 1550 and 1720 Ma,whereas zircons from the rhyodacitic porphyry yield εHf(t) values of-6.9 to-10.1 and Hf model ages between 1621 and 1823 Ma.These zircon Hf model ages are similar to the whole rock Nd model ages(1486 to 1911 Ma).Combined with other geochemical characteristics,the Xiangshan rhyodacite and rhyodacitic porphyry may have been derived from partial melting of the Paleo-Mesoproterozoic metamorphic rocks from the Xiangshan basement,without any significant addition of mantle-derived magma.Contribution of basement of this age is also supported by finding a Paleoproterozoic xenocrystic zircon core in the rhyodacite sample.展开更多
Highly precise 40Ar-39Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7-124.3 Ma, and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rock...Highly precise 40Ar-39Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7-124.3 Ma, and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rocks have relatively high (87Sr/86Sr)i ratios ( 0.708715-0.711418) and distinctly negative εNd values ( -11.47--17.54), and are enriched in radiogenic lead (206Pb/204Pb=17.341-17.622, 207Pb/204Pb=15.525-15.538, 208Pb/204Pb=37.563-37.684). Similarly, the lamprophyres also have quite low εNd values (-11.57 - -19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings, and extensive comparisons of the Sr, Nd isotopic composi-tions with that of the related simultaneous rocks, it is con-cluded that the potash-rich volcanic rocks and lamprophyres in western Shandong Province were most possibly derived from the partial melting展开更多
Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongg...Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongge,and Baima deposits,are well described in the literature and are hosted in layered mafic-ultramafic intrusions in the Panxi region,the central ELIP.The same type of ELIP- related deposits also occur far to the south and include the Anyi deposit,about 130 km south of Panzhihua,and the Mianhuadi deposit in the Red River fault zone.The Anyi deposit is relatively small but is similarly hosted in a layered mafic intrusion.The Mianhuadi deposit has a zircon U-Pb age of～260 Ma and is thus contemporaneous with the ELIP.This deposit was variably metamorphosed during the Indosinian orogeny and Red River faulting.Compositionally,magnetite of the Mianhuadi deposit contains smaller amounts of Ti and V than that of the other deposits,possibly attributable to the later metamorphism.The distribution of the oxide ore deposits is not related to the domal structure of the ELIP.One major feature of all the oxide deposits in the ELIP is the spatial association of oxide-bearing gabbroic intrusions,syenitic plutons and high-Ti flood basalts.Thus,we propose that magmas from a mantle plume were emplaced into a shallow magma chamber where they were evolved into a field of liquid immiscibility to form two silicate liquids,one with an extremely Fe-Ti-rich gabbroic composition and the other syenitic.An immiscible Fe-Ti-（P） oxide melt may then separate from the mafic magmas to form oxide deposits.The parental magmas from which these deposits formed were likely Fe-Ti-rich picritic in composition and were derived from enriched asthenospheric mantle at a greater depth than the magmas that produced sulfide-bearing intrusions of the ELIP.展开更多
Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious biodiversity loss with fragile ecological problems. Even thoug...Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious biodiversity loss with fragile ecological problems. Even though increasing attentions had been paid to this issue, we still lacked efficient methods to assess the change of plant biodiversity at medium/large scale due to the poor data and co-existing multiple habitat types. This study proposed an integrated method combining InVEST-habitat quality model, NPP and landscape pattern indexes to analyze the spatial heterogeneity of plant biodiversity and its spatiotemporal change on raster cell scale. The results indicated that plant biodiversity service was high in Bailongjiang watershed with obvious spatial pattern variations. The land area containing higher plant biodiversity were 3161 km2, which mainly distributed in the National Nature Reserve and forestry area. While the areas with lower plant biodiversity accounted for 37.67% and mainly distributed in the valleys between Zhouqu-Wudu-Wenxian County, the valley of Minjiang in Tanchang County and alpine mountain snow-covered regions. During 1990–2010, plant biodiversity level tended to increase and the higher plant biodiversity area increased from 14.13% to 17.15% due to ecological restoration and afforestation, while plant biodiversity decreased in the area with intensive human activities, such as cultivated land, urban and rural land. The results showed that combining InVEST-habitat quality model, NPP and landscape pattern indexes can effective reveal mountain plant biodiversity change. The study was useful for plant biodiversity conservation policy-making and human activity management for the disaster-impacted mountainous areas in China.展开更多
According to the study on the peripheral orogenic belts of the Junggar basin and combined with the interpretation of geophysical data, this paper points out that there is an Early Paleozoic basement of immature contin...According to the study on the peripheral orogenic belts of the Junggar basin and combined with the interpretation of geophysical data, this paper points out that there is an Early Paleozoic basement of immature continental crust in the Junggar area, which is mainly composed of Neoproterozoic-Ordovician oceanic crust and weakly metamorphosed covering sedimentary rocks. The Late Paleozoic tectonism and mineralization were developed on the basement of the Early Paleozoic immature continental crust. The Junggar metallogenic province is dominated by Cr, Cu, Ni and Au mineralization. Those large and medium-scale deposits are mainly distributed along the deep faults and particularly near the ophiolitic melange zones, and formed in the Late Paleozoic with the peak of mineralization occurring in the Carboniferous-Permian post-collisional stage. The intrusions related to Cu, Ni and Au mineralization generally have low Is, and positive εNd(t) values. The δ34S values of the ore deposits are mostly near zero, and the lead isotopes are mostly of normal lead. All these indicate that the ore-forming material comes either directly from the mantle-derived magma (for chromite and Cu-Ni deposits) or from recirculation of the basement material of the Early Paleozoic immature crust (for most Cu and Au deposits).展开更多
文摘The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of Jiangsu. 14 metals, including Zn, Cu, Pb, Cd, Cr, Ni, Mo, Mn, Ba, Co, Sr, Ti, As and Hg, were analyzed after samples acid digestion. The results showed that the most feed samples contained high concentration of metals exceeding National Hygienical Standard for Feeds. Meanwhile, it was found that Cu, Zn, Pb, Cd and Cr concentrations in animal manures were also high, for example, Cu concentration in a manure sample reached to as much as 1726 3 mg/kg. Heavy metals loading quantities in soil per year were then calculated when metals contaminated organic fertilizers were applied, and its effects on soil environmental quality were further evaluated.
文摘Background:The 2019 novel coronavirus(2019-nCoV)causing an outbreak of pneumonia in Wuhan,Hubei province of China was isolated in January 2020.This study aims to investigate its epidemiologic history,and analyze the clinical characteristics,treatment regimens,and prognosis of patients infected with 2019-nCoV during this outbreak.Methods:Clinical data from 1372019-nCoV-infected patients admitted to the respiratory departments of nine tertiary hospitals in Hubei province from December 30,2019 to January 24,2020 were retrospectively collected,including general status,clinical manifestations,laboratory test results,imaging characteristics,and treatment regimens.Results:None of the 137 patients(61 males,76 females,aged 20-83 years,median age 57 years)had a definite history of exposure to Huanan Seafood Wholesale Market.Major initial symptoms included fever(112/137,81.8%),coughing(66/137,48.2%),and muscle pain or fatigue(44/137,32.1%),with other,less typical initial symptoms observed at low frequency,including heart palpitations,diarrhea,and headache.Nearly 80%of the patients had normal or decreased white blood cell counts,and 72.3%(99/137)had lymphocytopenia.Lung involvement was present in all cases,with most chest computed tomography scans showing lesions in multiple lung lobes,some of which were dense;ground-glass opacity co-existed with consolidation shadows or cord-like shadows.Given the lack of effective drugs,treatment focused on symptomatic and respiratory support.Immunoglobulin G was delivered to some critically ill patients according to their conditions.Systemic corticosteroid treatment did not show significant benefits.Notably,early respiratory support facilitated disease recovery and improved prognosis.The risk of death was primarily associated with age,underlying chronic diseases,and median interval from the appearance of initial symptoms to dyspnea.Conclusions:The majority of patients with 2019-nCoV pneumonia present with fever as the first symptom,and most of them still showed typical manifestations of v
基金The paper is supported by the National Natural Science Foundation of China （Grant Nos. 40420120135 and 40072060）.
文摘By using the SHRIMP U-Pb and single zircon stepwise evaporation methods, the authors have obtained some results for granitoids from eastern Hebei Province. The Yuhuzhai hyperthene tonalitic granite was formed 2550 Ma ago, the Qingyangshu gabbroic gneiss 2536 Ma, the Yinmahe granodioritic gneiss near Lücao, Lulong County, 2533 Ma, the gabbro-dioritic gneiss near Longwan, Qianxi County, 2518-2515 Ma, the Qiuhuayu trondjemitic gneiss at Zunhua 2515 Ma, the Xiaoguanzhuang tonalitic gneiss at Zunhua 2495 Ma, and the Cuizhangzi gneiss in Qianxi County 2492 Ma. These geochronilogical data demonstrate that, though diverse in composition, type and origin, the granitic gneisses in eastern Hebei Province were emplaced and crystallized in a rather short period of magmatic activity. The formation of such a great amount of gneisses in this small time gap suggests that it was a critical crust accretion stage at the end of Neoarchean. The fact that granitoids of various types occurred at the same time implies a large-scale underplating （mantle plume） activity, which was then responsible for the crust accretion.
基金supported by the National Natural Science Foundation of China(31727901)。
文摘The fall armyworm(FAW),Spodoptera frugiperda is one of the most damaging crop pests,and it has become major threat to the food security of many countries.In order to monitor possible invasion of this pest into China,a searchlight trap was established in March 2018 in western Yunnan Province,China,where it has served as the"first station"for many pests that have migrated from Myanmar to China.A number of suspected FAW moths were captured and identified by DNA sequencing.The results showed that the FAW moth was first captured on December 11 and formed its first immigration peak in mid-December 2018.DNA detection revealed that the early invading FAW population was the"corn-strain".The field survey indicated that the pest mainly colonized corn in Pu’er,Dehong and Baoshan areas.Migration trajectory simulation implied that the moths might have mainly come from the eastern area in the mid-latitude region of Myanmar(20-25°N,94-100°E).This case study confirmed the first immigration of FAW into China,and will be helpful for guiding monitoring and management work to control this pest.
基金supported by NSC grant 102-2628-M-003-001-MY4 to JGS
文摘The late Permian Emeishan large igneous province （EL1P） covers -0.3× 10-6 kmL of the western margin of the Yangtze Block and Tibetan Plateau with displaced, correlative units in northern Vietnam （Song Da zone）. The ELIP is of particular interest because it contains numerous world-class base metal deposits and is contemporaneous with the late Capitanian （-260 Ma） mass extinction. The flood basalts are the signature feature of the ELIP but there are also ultramafic and silicic volcanic rocks and layered mafic- ultramafic and silicic plutonic rocks exposed. The EL1P is divided into three nearly concentric zones （i.e. inner, middle and outer） which correspond to progressively thicker crust from the inner to the outer zone. The eruptive age of the ELIP is constrained by geological, paleomagnetic and geochronological evidence to an interval of 〈3 Ma. The presence of picritic rocks and thick piles of flood basalts testifies to high temperature thermal regime however there is uncertainty as to whether these magmas were derived from the subcontinental lithospheric mantle or sub-lithospheric mantle （i.e. asthenosphere or mantle plume） sources or both. The range of Sr （Isr ≈ 0.7040-0.7132）, Nd （ENd（t） ≈ -14 tO ＋8）, Pb （206-pb/204-pb1 ≈ 17.9-20.6） and Os （Yos ≈ -5 to ＋11） isotope values of the ultramafic and mafic rocks does not permit a conclusive answer to ultimate source origin of the primitive rocks but it is clear that some rocks were affected by crustal contamination and the presence of near-depleted isotope compo- sitions suggests that there is a sub-lithospheric mantle component in the system. The silicic rocks are derived by basaltic magmas/rocks through fractional crystallization or partial melting, crustal melting or by interactions between mafic and crustal melts. The formation of the Fe-Ti-V oxide-ore deposits is probably due to a combination of fractional crystallization of Ti-rich basalt and fluxing of C02-rich fluids whereas the Ni-Cu-（PGE） deposits a
基金This work was supported by the Chinese Academy of Sciences (Gram Nos. KZCX2-102 and KZCX3-113)the Ministry of Science and Technology of China (Grant No. G1999043209)the National Natural Science Foundation of China (Grant No. 40002007)
文摘The genesis of Indo-Sinian granitic plutons with peraluminous and potassium-rich affinities from Hunan Province, China has been investigated by numerical modeling using the numerical code FLAC. On the basis of the regional geological evolution in South China, we employed a realistic numerical model in an attempt to unravel the influences of basaltic underplating and tectonic crustal thickening on the crustal anatexis. Heat production derived from basaltic underplating (e.g. ca. 220 Ma gabbro xenoliths) can result in dehydration melting of fluid-bearing minerals in crustal rocks such as gneisses and metapelites, but its effect is limited in a relatively short time span (5-15 Ma) and on a small scale. Accordingly, it is very difficult for basaltic underplating to generate the large-scale Indo-Sinian granitic bathliths unless voluminous mafic magmas had been underplated at the lower/middle crust during this period. Alternatively, crustal thickening induced by tectonic compression can also lead to geothermal elevation, during which the temperature at the boundary between lower and middle crusts can be up to or greater than 700°C, triggering dehydration melting of muscovite in gneiss and metapelite. The proportion of melts from muscovite-induced dehydration melting is close to critical melt percentage (?20%) once the thickening factor reaches 1.3. These melts can be effectively transferred to the crust-level magma chamber and form large-scale granitic batholiths. In combination with the Indo-Sinian convergent tectonic setting in South China as well as sparse outcrops of contemporary mafic igneous rocks, we consider that tectonic crustal thickening is likely to be the predominant factor controlling the formation of the Indo-Sinian peraluminous and potassium-rich granitoids in Hunan Province.
基金supported by Key Project from the Ministry of Education (Grant No.306007)
文摘The Xiangshan uranium ore field is the largest volcanic rock hosted uranium deposit in China.The host rock is a volcanic intrusive complex,including rhyodacite,porphyroclastic lava and late stage sub-volcanic rocks.In this study,zircons from an early stage rhyodacite and a late stage rhyodacite porphyry were dated by SHRIMP and LA-ICP-MS U-Pb methods,and their Hf isotopic compositions were measured by LA-MC-ICP-MS.206Pb/238U ages of 135.1±1.7 and 134.8±1.1 Ma were obtained for the rhyodacite and rhyodacitic porphyry,respectively.These accurate ages indicate that the Xiangshan volcanic-intrusive complex formed in the Early Cretaceous rather than in the Late Jurassic,as concluded in some previous studies.By the Early Cretaceous,the tectonic setting of the area has evolved into a back-arc extensional setting,possibly related to subduction of the paleo-Pacific plate.The close ages of the(early) eruptive rhyodacite and the(late) hypabyssal rhyodacitic porphyry shows that the Xiangshan volcanism was intensive and concentrated in a short time.Zircons from the rhyodacite show negative εHf(t) values of-5.7 to-8.5,with Hf depleted mantle model ages between 1550 and 1720 Ma,whereas zircons from the rhyodacitic porphyry yield εHf(t) values of-6.9 to-10.1 and Hf model ages between 1621 and 1823 Ma.These zircon Hf model ages are similar to the whole rock Nd model ages(1486 to 1911 Ma).Combined with other geochemical characteristics,the Xiangshan rhyodacite and rhyodacitic porphyry may have been derived from partial melting of the Paleo-Mesoproterozoic metamorphic rocks from the Xiangshan basement,without any significant addition of mantle-derived magma.Contribution of basement of this age is also supported by finding a Paleoproterozoic xenocrystic zircon core in the rhyodacite sample.
基金This work was supported by the Major State Basic Research Program (Grant No. G1999043202) the National Natural Science Foundation of China (Grant No. 49872028).
文摘Highly precise 40Ar-39Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7-124.3 Ma, and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rocks have relatively high (87Sr/86Sr)i ratios ( 0.708715-0.711418) and distinctly negative εNd values ( -11.47--17.54), and are enriched in radiogenic lead (206Pb/204Pb=17.341-17.622, 207Pb/204Pb=15.525-15.538, 208Pb/204Pb=37.563-37.684). Similarly, the lamprophyres also have quite low εNd values (-11.57 - -19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings, and extensive comparisons of the Sr, Nd isotopic composi-tions with that of the related simultaneous rocks, it is con-cluded that the potash-rich volcanic rocks and lamprophyres in western Shandong Province were most possibly derived from the partial melting
基金supported by the Research Grant Council of Hong Kong(HKU707012P)to MFZfrom a Chinese National "973" project (2011CB808903)+1 种基金a "CAS Hundred Talents" project under Chinese Academy of Sciences to CYWSouth African National Science Foundation Grant SA/China Project 67220 to SP and MFZ
文摘Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongge,and Baima deposits,are well described in the literature and are hosted in layered mafic-ultramafic intrusions in the Panxi region,the central ELIP.The same type of ELIP- related deposits also occur far to the south and include the Anyi deposit,about 130 km south of Panzhihua,and the Mianhuadi deposit in the Red River fault zone.The Anyi deposit is relatively small but is similarly hosted in a layered mafic intrusion.The Mianhuadi deposit has a zircon U-Pb age of～260 Ma and is thus contemporaneous with the ELIP.This deposit was variably metamorphosed during the Indosinian orogeny and Red River faulting.Compositionally,magnetite of the Mianhuadi deposit contains smaller amounts of Ti and V than that of the other deposits,possibly attributable to the later metamorphism.The distribution of the oxide ore deposits is not related to the domal structure of the ELIP.One major feature of all the oxide deposits in the ELIP is the spatial association of oxide-bearing gabbroic intrusions,syenitic plutons and high-Ti flood basalts.Thus,we propose that magmas from a mantle plume were emplaced into a shallow magma chamber where they were evolved into a field of liquid immiscibility to form two silicate liquids,one with an extremely Fe-Ti-rich gabbroic composition and the other syenitic.An immiscible Fe-Ti-（P） oxide melt may then separate from the mafic magmas to form oxide deposits.The parental magmas from which these deposits formed were likely Fe-Ti-rich picritic in composition and were derived from enriched asthenospheric mantle at a greater depth than the magmas that produced sulfide-bearing intrusions of the ELIP.
基金National Natural Science Foundation of China,No.41771196,No.41761039,No.41271199
文摘Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious biodiversity loss with fragile ecological problems. Even though increasing attentions had been paid to this issue, we still lacked efficient methods to assess the change of plant biodiversity at medium/large scale due to the poor data and co-existing multiple habitat types. This study proposed an integrated method combining InVEST-habitat quality model, NPP and landscape pattern indexes to analyze the spatial heterogeneity of plant biodiversity and its spatiotemporal change on raster cell scale. The results indicated that plant biodiversity service was high in Bailongjiang watershed with obvious spatial pattern variations. The land area containing higher plant biodiversity were 3161 km2, which mainly distributed in the National Nature Reserve and forestry area. While the areas with lower plant biodiversity accounted for 37.67% and mainly distributed in the valleys between Zhouqu-Wudu-Wenxian County, the valley of Minjiang in Tanchang County and alpine mountain snow-covered regions. During 1990–2010, plant biodiversity level tended to increase and the higher plant biodiversity area increased from 14.13% to 17.15% due to ecological restoration and afforestation, while plant biodiversity decreased in the area with intensive human activities, such as cultivated land, urban and rural land. The results showed that combining InVEST-habitat quality model, NPP and landscape pattern indexes can effective reveal mountain plant biodiversity change. The study was useful for plant biodiversity conservation policy-making and human activity management for the disaster-impacted mountainous areas in China.
基金the Major State Basic Research Programs of the People’s Republic of China(No.2001CB409806).
文摘According to the study on the peripheral orogenic belts of the Junggar basin and combined with the interpretation of geophysical data, this paper points out that there is an Early Paleozoic basement of immature continental crust in the Junggar area, which is mainly composed of Neoproterozoic-Ordovician oceanic crust and weakly metamorphosed covering sedimentary rocks. The Late Paleozoic tectonism and mineralization were developed on the basement of the Early Paleozoic immature continental crust. The Junggar metallogenic province is dominated by Cr, Cu, Ni and Au mineralization. Those large and medium-scale deposits are mainly distributed along the deep faults and particularly near the ophiolitic melange zones, and formed in the Late Paleozoic with the peak of mineralization occurring in the Carboniferous-Permian post-collisional stage. The intrusions related to Cu, Ni and Au mineralization generally have low Is, and positive εNd(t) values. The δ34S values of the ore deposits are mostly near zero, and the lead isotopes are mostly of normal lead. All these indicate that the ore-forming material comes either directly from the mantle-derived magma (for chromite and Cu-Ni deposits) or from recirculation of the basement material of the Early Paleozoic immature crust (for most Cu and Au deposits).
