Lithium is one of the important strategic energy metals,which is in short supply in China.There are three major types of lithium deposits:brine and salt lake type,highly differentiated granite or pegmatite type,and ca...Lithium is one of the important strategic energy metals,which is in short supply in China.There are three major types of lithium deposits:brine and salt lake type,highly differentiated granite or pegmatite type,and carbonate-clay type.In recent years,some new types of lithium deposits have also begun to receive great attention and subject recent research.There are many crypto-explosive breccia pipe type deposits in the world,including copper,gold,lead,zinc,tungsten and tin deposits,but little is known about this type of lithium deposit.This paper introduces the latest research results of the Weilasituo Sn-Li-Rb polymetallic deposit in Inner Mongolia(NE China),which occurs in the middlesouthern section of the Great Xing’an Range metallogenic belt.A remarkable feature of this deposit is the coexistence of various mineralization types,including granite type Rb and Sn-Zn,hydrothermal crypto-explosive breccia pipe type Li-Rb,quartz vein type Sn-Zn and sulfide vein type Pb-Zn-Ag mineralization.Among them,hydrothermal crypto-explosive breccia pipe type Li-Rb deposit is currently very rare at home and abroad,which is likely a new type of rare metal deposit that worthy of our attention.This paper systematically summarizes the geology,alteration and mineralization,geochemistry,isotopes and geochronology of the Weilasituo deposit,and establishes a new petrogenic and metallogenic model.展开更多
In order to evaluate the contamination of the Moroccan Mediterranean coasts by persistent organic pollutants we studied hydrocarbons and linear alkylbenzenes in bivalve tissues (cockles) collected seasonally from seve...In order to evaluate the contamination of the Moroccan Mediterranean coasts by persistent organic pollutants we studied hydrocarbons and linear alkylbenzenes in bivalve tissues (cockles) collected seasonally from several points along the western Moroccan coasts in the Mediterranean Sea. Two fractions corresponding to non aromatic and aromatic hydrocarbons were analyzed by GC/FID and GC/MS. Non aromatic hydrocarbon concentrations vary in the range of 24.1 - 2731 μg/g dry weight (dw) while total n-alkanes vary from 2.2 to 68.2 μg/g. Few exceptions were noted with values up to 243 μg/g (dw), which is high compared to other Mediterranean sites. The presence of an important unresolved complex mixture (UCM) indicated a significant petroleum contamination, confirmed by the identification of 17α(H), 21β(H) hopanes. Biogenic contributions were also detected within the n-alkane distribution (n-C17, n-C18, n-C27, n-C29, n-C17, /Pr, n-C18, /Ph) and by the presence of alkenes. C13, and C14, linear alkylbenzenes were found at concentrations of 478 - 1954 ng/g. and point to pollutant inputs from wastewaters. Polycyclic aromatic hydrocarbons were present in low concentrations below the GC detection limit. The observed seasonal and spatial variations were linked to the magnitude of inputs from marine and land-based pollutant discharges.展开更多
The Ertix gold belt is located on the boundary of the Kalatongkearc and the Kelan back-arc basin of D-C1. Most scholars used to interpret the formation and distribution of the gold deposits in the Ertix tectonic belt ...The Ertix gold belt is located on the boundary of the Kalatongkearc and the Kelan back-arc basin of D-C1. Most scholars used to interpret the formation and distribution of the gold deposits in the Ertix tectonic belt in terms of the petrogenic and metallogenic models for active continental margins. However, enormous data of isotopic dating and geologic research show that the mineralization was obviously later than the oceanic subduction, whereas exactly simultaneous with the collisional orogenesis during C2-P, especially at the transition stage from collisional compression to extension. Based on study of metallogenic time, tectonic background, ore geology, ore fluid nature, ore material source, etc., we reveal that all the gold deposits possess the character of orogenic deposits formed in collisional orogenic system, and that their ore-forming materials mainly have derived from the stratigraphic terranes south to individual deposits. Accordingly, the theoretical tectonic model for collisional metallogenesis and petrogenesis is employed to explain the formation of the Ertix gold belt and to determine the gold exploration directions.展开更多
Polycyclic aromatic hydrocarbons(PAHs)are large class of hydrophobic,semi-volatile organic contaminants that may enter the environment from both natural sources and anthropogenic activities.Pyrogenic PAHs arise from t...Polycyclic aromatic hydrocarbons(PAHs)are large class of hydrophobic,semi-volatile organic contaminants that may enter the environment from both natural sources and anthropogenic activities.Pyrogenic PAHs arise from the incomplete combustion of fossil fuels and organic matter and following dispersal via long-range transport and may subsequently deposit in surface waters,soils and sediments of remote regions,including the Arctic.The current review summarizes and discusses Arctic data that is available for combustion-derived PAHs between 2004 and early 2018,focusing largely on data collected from remote,unexploited Arctic regions and from studies that provide some evidence of a pyrogenic origin.The increasing use of attribution ratios,which aid in discriminating PAHs from petrogenic or pyrogenic sources,suggest PAHs found in Arctic marine waters and sediment predominantly originate from natural underwater seeps,while those measured in air,freshwater,and terrestrial environments are likely to have originated from atmospheric and combustion-derived sources.Modeling efforts indicate that atmospheric PAHs in the Canadian and Norwegian Arctic are likely to have originated in the northern hemisphere e predominantly from Western Russia,northern Europe,and North America.East Asia appears to be a minor source of PAHs to the Arctic,despite contributing more than 50%of global PAH emissions.In comparison to the growing data for atmospheric PAHs,environmental data for these compounds in terrestrial and freshwater environments remain scarce.PAHs have been detected in Arctic biota from terrestrial,freshwater and marine environments,indicating exposure,however,levels are generally low,as most organisms efficiently metabolize parent PAHs.Globally,PAH emissions are expected to decline in the future,however models suggest the Arctic may not experience the same magnitude of decline projected for other world regions.Furthermore,future changes in climate may contribute to a re-volatilization of environmental PAHs,providing a source of secondary emissions to the Arctic atmosphere,emphasizing the importance of future monitoring for understanding the sources,fate and impacts of PAHs in the Arctic.展开更多
基金financially supported by projects from the National Natural Science Foundation of China(No.92162323)the National Key R&D Program of China(No.2017YFC0602405)。
文摘Lithium is one of the important strategic energy metals,which is in short supply in China.There are three major types of lithium deposits:brine and salt lake type,highly differentiated granite or pegmatite type,and carbonate-clay type.In recent years,some new types of lithium deposits have also begun to receive great attention and subject recent research.There are many crypto-explosive breccia pipe type deposits in the world,including copper,gold,lead,zinc,tungsten and tin deposits,but little is known about this type of lithium deposit.This paper introduces the latest research results of the Weilasituo Sn-Li-Rb polymetallic deposit in Inner Mongolia(NE China),which occurs in the middlesouthern section of the Great Xing’an Range metallogenic belt.A remarkable feature of this deposit is the coexistence of various mineralization types,including granite type Rb and Sn-Zn,hydrothermal crypto-explosive breccia pipe type Li-Rb,quartz vein type Sn-Zn and sulfide vein type Pb-Zn-Ag mineralization.Among them,hydrothermal crypto-explosive breccia pipe type Li-Rb deposit is currently very rare at home and abroad,which is likely a new type of rare metal deposit that worthy of our attention.This paper systematically summarizes the geology,alteration and mineralization,geochemistry,isotopes and geochronology of the Weilasituo deposit,and establishes a new petrogenic and metallogenic model.
文摘In order to evaluate the contamination of the Moroccan Mediterranean coasts by persistent organic pollutants we studied hydrocarbons and linear alkylbenzenes in bivalve tissues (cockles) collected seasonally from several points along the western Moroccan coasts in the Mediterranean Sea. Two fractions corresponding to non aromatic and aromatic hydrocarbons were analyzed by GC/FID and GC/MS. Non aromatic hydrocarbon concentrations vary in the range of 24.1 - 2731 μg/g dry weight (dw) while total n-alkanes vary from 2.2 to 68.2 μg/g. Few exceptions were noted with values up to 243 μg/g (dw), which is high compared to other Mediterranean sites. The presence of an important unresolved complex mixture (UCM) indicated a significant petroleum contamination, confirmed by the identification of 17α(H), 21β(H) hopanes. Biogenic contributions were also detected within the n-alkane distribution (n-C17, n-C18, n-C27, n-C29, n-C17, /Pr, n-C18, /Ph) and by the presence of alkenes. C13, and C14, linear alkylbenzenes were found at concentrations of 478 - 1954 ng/g. and point to pollutant inputs from wastewaters. Polycyclic aromatic hydrocarbons were present in low concentrations below the GC detection limit. The observed seasonal and spatial variations were linked to the magnitude of inputs from marine and land-based pollutant discharges.
基金The authors thank Professors Tu Guangchi, Xiao Xuchang, He Guoqi, Ai Yongfu, Qin Kezhang and Wei QiyingDoctors Zhang Zengjie, Zhang Jing and Li Chao for their kindest help This work was supported by the Ministry of Science and Technology of China (Gr
文摘The Ertix gold belt is located on the boundary of the Kalatongkearc and the Kelan back-arc basin of D-C1. Most scholars used to interpret the formation and distribution of the gold deposits in the Ertix tectonic belt in terms of the petrogenic and metallogenic models for active continental margins. However, enormous data of isotopic dating and geologic research show that the mineralization was obviously later than the oceanic subduction, whereas exactly simultaneous with the collisional orogenesis during C2-P, especially at the transition stage from collisional compression to extension. Based on study of metallogenic time, tectonic background, ore geology, ore fluid nature, ore material source, etc., we reveal that all the gold deposits possess the character of orogenic deposits formed in collisional orogenic system, and that their ore-forming materials mainly have derived from the stratigraphic terranes south to individual deposits. Accordingly, the theoretical tectonic model for collisional metallogenesis and petrogenesis is employed to explain the formation of the Ertix gold belt and to determine the gold exploration directions.
基金We thank the Arctic Monitoring and Assessment Programme(AMAP)and the national programs in the circumpolar countries for their funding and support of this work.We are especially grateful to Simon Wilson,Cynthia de Wit,and the numerous reviewers that were a part of this process.We are thankful to the northern communities in circumpolar regions for their cooperation and collection of biological samples that yielded much of the data reviewed here.We also thank Canada's Northern Contaminants Program(NCP)for providing air data from the station of Alert and the Swedish Environmental Protection Agency and Finnish Meteorological Institute(FMI)for providing the air data for Pallas.
文摘Polycyclic aromatic hydrocarbons(PAHs)are large class of hydrophobic,semi-volatile organic contaminants that may enter the environment from both natural sources and anthropogenic activities.Pyrogenic PAHs arise from the incomplete combustion of fossil fuels and organic matter and following dispersal via long-range transport and may subsequently deposit in surface waters,soils and sediments of remote regions,including the Arctic.The current review summarizes and discusses Arctic data that is available for combustion-derived PAHs between 2004 and early 2018,focusing largely on data collected from remote,unexploited Arctic regions and from studies that provide some evidence of a pyrogenic origin.The increasing use of attribution ratios,which aid in discriminating PAHs from petrogenic or pyrogenic sources,suggest PAHs found in Arctic marine waters and sediment predominantly originate from natural underwater seeps,while those measured in air,freshwater,and terrestrial environments are likely to have originated from atmospheric and combustion-derived sources.Modeling efforts indicate that atmospheric PAHs in the Canadian and Norwegian Arctic are likely to have originated in the northern hemisphere e predominantly from Western Russia,northern Europe,and North America.East Asia appears to be a minor source of PAHs to the Arctic,despite contributing more than 50%of global PAH emissions.In comparison to the growing data for atmospheric PAHs,environmental data for these compounds in terrestrial and freshwater environments remain scarce.PAHs have been detected in Arctic biota from terrestrial,freshwater and marine environments,indicating exposure,however,levels are generally low,as most organisms efficiently metabolize parent PAHs.Globally,PAH emissions are expected to decline in the future,however models suggest the Arctic may not experience the same magnitude of decline projected for other world regions.Furthermore,future changes in climate may contribute to a re-volatilization of environmental PAHs,providing a source of secondary emissions to the Arctic atmosphere,emphasizing the importance of future monitoring for understanding the sources,fate and impacts of PAHs in the Arctic.
