Rare earth elements(REEs)can be used to trace source materials and identify their provenances,because of significant conservation and immobility during chemical alteration processes after erosion of materials from the...Rare earth elements(REEs)can be used to trace source materials and identify their provenances,because of significant conservation and immobility during chemical alteration processes after erosion of materials from the provenance.This study focused on the temporal variation of REEs for columnar sediments from the mouth of Jiaozhou Bay in North China to understand the potential controls for the geochemical variations of sediments.Through extraction experiments,we identified that the residual fraction is the main host for REEs compared with other fractions(i.e.,exchangeable and carbonate fraction,easily reducible oxides fraction,reducible oxides fraction,magnetite fraction).REE ratios(e.g.,La_(N)/Sm_(N)and La_(N)/Yb_(N);N:normalized by chondrite)lack correlations with grain size or the chemical index of alteration(CIA),which is correlated with major elements.All these indicate that these REE variations reflect the varying contribution of source materials from different provenances instead of grain size or chemical weathering effects.REE ratios(e.g.,La_(N)/Sm_(N)and La_(N)/Yb_(N))remain relatively constant until the depth of roughly 40 cm(equivalent to the year 1995),and show obvious changes beyond this depth.Compared REE characteristics of Jiaozhou Bay with those of neighboring rivers and bedrocks,the relative contributions of Dagu River-Jiaolai River,and Licun River may have been increased during the sedimentary processes,which could be caused by the construction of reservoir and related change of aquaculture(e.g.,rapid accumulation of organic materials).展开更多
The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be...The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.展开更多
基金Supported by the National Natural Science Foundation of China (No.41776069)the Science and Technology Innovation Project of Laoshan Laboratory (No.LSKJ202202905)the Special Project of Strategic Leading Science and Technology of Chinese Academy of Sciences (No.XDB42020302)。
文摘Rare earth elements(REEs)can be used to trace source materials and identify their provenances,because of significant conservation and immobility during chemical alteration processes after erosion of materials from the provenance.This study focused on the temporal variation of REEs for columnar sediments from the mouth of Jiaozhou Bay in North China to understand the potential controls for the geochemical variations of sediments.Through extraction experiments,we identified that the residual fraction is the main host for REEs compared with other fractions(i.e.,exchangeable and carbonate fraction,easily reducible oxides fraction,reducible oxides fraction,magnetite fraction).REE ratios(e.g.,La_(N)/Sm_(N)and La_(N)/Yb_(N);N:normalized by chondrite)lack correlations with grain size or the chemical index of alteration(CIA),which is correlated with major elements.All these indicate that these REE variations reflect the varying contribution of source materials from different provenances instead of grain size or chemical weathering effects.REE ratios(e.g.,La_(N)/Sm_(N)and La_(N)/Yb_(N))remain relatively constant until the depth of roughly 40 cm(equivalent to the year 1995),and show obvious changes beyond this depth.Compared REE characteristics of Jiaozhou Bay with those of neighboring rivers and bedrocks,the relative contributions of Dagu River-Jiaolai River,and Licun River may have been increased during the sedimentary processes,which could be caused by the construction of reservoir and related change of aquaculture(e.g.,rapid accumulation of organic materials).
基金MoES (Govt of India)for his financial assistance to our project (GPP364).
文摘The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.
