Using a neutron activation analysis technique, which involves gamma-spectrometry with a Ge(Li) detector coupled to a S40 multichannel analyzer and interfaced to a PDP-11 computer, we determined thirty-eight elements i...Using a neutron activation analysis technique, which involves gamma-spectrometry with a Ge(Li) detector coupled to a S40 multichannel analyzer and interfaced to a PDP-11 computer, we determined thirty-eight elements in sediments from the lower reach (downstream from Jinan) and estuary of Huanghe. The results are discussed in this paper.From inter-elemental correlations, it ts found that a large number of metals (Mn.As, Co, Cr.Cs, Rb, Sc, Ti, Ta, V and Zn) correlate positively with Fe. Ba and Ca correlate positively with Al. Whereas some elements (e. g. , Ti and lanthanides) show no correlation with either Fe or Al. On the other hand, Hf and Zr show a negative correlation with Fe. Elements which tend to be scavenged by Fe and Al colloids or suspended particles are enriched in sediments at the Huanghe Estuary relative to its lower reach. On the other hand, the contents of some elements (e. g. , Zr,Hf,U, Ba, etc. )are higher in sediments from the lower reach of Huanghe than in the estuarine sediments,which may be related to the sorting during deposition of source materials. On the basis of their chemical property and geochemical behavior, the 38 elements we studied are classified into seven groups. (1) weathering-prone elements,group A:K,Rb, Cs and Na; (2) weathering-prone elements, group B:Mg, Ca, Ba and Al; (3) transition elements:Fe, Co.Ni, Zn, As, Sb, Mn, Cr, W,Mo,V, Ta and Sc; (4) rare elements:group A (Zr and Hf) and group B (Ti); (5) rare earth elements:the lanthanides; (6) halogens: Cl and Br; amd (7) natural radioactive elements:U and Th. The basis for this classification is discussed and we emphasize that geochemical associations of elements in the natural environment are not necessarily in accord with their chemical properties as dictated by position at the periodic table.展开更多
1 Introduction Geological studies established on several sections in Lanping-Simao basin have shown that the salt-bearing strata of Mengyejing formation(Yunlong Fm.in Lanping basin)are constituted by an alternation of...1 Introduction Geological studies established on several sections in Lanping-Simao basin have shown that the salt-bearing strata of Mengyejing formation(Yunlong Fm.in Lanping basin)are constituted by an alternation of salt layers and interbedded facies.The latter consists mainly of mudstones,and mudstone-rich conglomerate.The mineralogy and geochemistry of salt-bearing beds and展开更多
Utility of geochemistry in mineral exploration is known since more than half-a-century.In reconnaissance diamond exploration,regolith geochemistry is a well known tool worldwide and helps in distinguishing bedrock
Qarhan Salt Lake is located in the eastern part of the Qaidam Basin,which is first discovered the large potash deposit in the late 1950s.The Bieletan section is located in the west of Qarhan Salt Lake,where saline sed...Qarhan Salt Lake is located in the eastern part of the Qaidam Basin,which is first discovered the large potash deposit in the late 1950s.The Bieletan section is located in the west of Qarhan Salt Lake,where saline sediment展开更多
1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich inf...1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich information on展开更多
Field and geochemical studies of the Bunu area,SW Nigeria,were carried out on gneiss-metasedimentary rocks that consist of migmatised gneiss,quartz-mica schist,and foliated and massive quartzites.These gneissmetasedim...Field and geochemical studies of the Bunu area,SW Nigeria,were carried out on gneiss-metasedimentary rocks that consist of migmatised gneiss,quartz-mica schist,and foliated and massive quartzites.These gneissmetasedimentary rocks are interbedded with meta-igneous rock(amphibolite),all of which are intruded by granitoid and cut by basic and felsic dykes.Geochemical data on major,trace,and rare Earth elements of these rocks from the area were used to speculate on the petrogenetic and geodynamic evolution of the rocks in the area.Compositionally,the metasedimentary rocks in the area have a restricted range of major oxides such as SiO_(2)and Al_(2)O_(3)with low average values of FeO,MnO,CaO,and PO.Concentrations of average values of HSFE such as Zr,Nb,and Y are moderately high in migmatitic gneiss,quartzmica schist,and low in both massive and foliated quartzite.ΣLREE average values are 124.25,132.41,and18.64 ppm respectively for migmatite gneiss,quartz-mica schist,and low in both massive and foliated quartzite.These rocks are also generally enriched in Ba,Cs,Pb,U,Cr,Rb,and Zr and depleted in Be,Sr,Ti,Mo,Th,and W.This enrichment–depletion in major oxides and trace elements of the rocks in this area is probably a consequence of the movement of metamorphic remobilized fluids within the rocks in the area during the Pan-African or earlier events as noted in the adjacent Egbe-Isanlu Schist belt.A further geochemical characterisation of the rocks in the area using Log(Na_(2)O/KO)vs Log(SiO_(2)/Al_(2)O_(3)indicates that while the protolith of migmatised gneiss and quartzmica schist are greywackes to litharenite in compositions that of quartzites are sublitharenite to quartz arenite.On the ternary plot of Al_(2)O_(3)-(CaO+Na_(2)O)-KO for metasedimentary rocks in the area,most migmatitic gneiss and quartz-mica schist rocks plot close to average shale while quartzites mostly tend to illite compositions and almost toward the Al_(2)O_(3)-apex of the diagram attesting to depletion of CaO and Na_(2)O with the removal of KO.CIA vs PIA plot of the rocks in the area shows that while migmatitic-gneiss and quartz-mica schist are moderately weathered,both massive and foliated quartzites are high to extremely weathered.They are all derived mostly from predominantly felsic igneous to quartzose sedimentary provenance and mostly emplaced in passive continental margins.These nature of the protoliths suggests gradual subsidence of the basin during its genesis,and/or tectonic stable or inactive environment from which the sediments were derived.展开更多
Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulph...Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation（FGD）-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the p H and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the p H value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2 Se, and HAs O2 are the aqueous complexes with the highest activities under acidic conditions.The speciation of Zn, Li, and Ni is not affected in spite of p H changes; these elements occur as free cations and associated to SO4 ^2 in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the p H of the FGD-gypsum leachates, which might be associated to the precipitation of Cu Se2 and Mo Se2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.展开更多
文摘Using a neutron activation analysis technique, which involves gamma-spectrometry with a Ge(Li) detector coupled to a S40 multichannel analyzer and interfaced to a PDP-11 computer, we determined thirty-eight elements in sediments from the lower reach (downstream from Jinan) and estuary of Huanghe. The results are discussed in this paper.From inter-elemental correlations, it ts found that a large number of metals (Mn.As, Co, Cr.Cs, Rb, Sc, Ti, Ta, V and Zn) correlate positively with Fe. Ba and Ca correlate positively with Al. Whereas some elements (e. g. , Ti and lanthanides) show no correlation with either Fe or Al. On the other hand, Hf and Zr show a negative correlation with Fe. Elements which tend to be scavenged by Fe and Al colloids or suspended particles are enriched in sediments at the Huanghe Estuary relative to its lower reach. On the other hand, the contents of some elements (e. g. , Zr,Hf,U, Ba, etc. )are higher in sediments from the lower reach of Huanghe than in the estuarine sediments,which may be related to the sorting during deposition of source materials. On the basis of their chemical property and geochemical behavior, the 38 elements we studied are classified into seven groups. (1) weathering-prone elements,group A:K,Rb, Cs and Na; (2) weathering-prone elements, group B:Mg, Ca, Ba and Al; (3) transition elements:Fe, Co.Ni, Zn, As, Sb, Mn, Cr, W,Mo,V, Ta and Sc; (4) rare elements:group A (Zr and Hf) and group B (Ti); (5) rare earth elements:the lanthanides; (6) halogens: Cl and Br; amd (7) natural radioactive elements:U and Th. The basis for this classification is discussed and we emphasize that geochemical associations of elements in the natural environment are not necessarily in accord with their chemical properties as dictated by position at the periodic table.
基金supported by the National Basic Research Program of China (2011CB403004)the National Natural Science Foundation of China (41303029)
文摘1 Introduction Geological studies established on several sections in Lanping-Simao basin have shown that the salt-bearing strata of Mengyejing formation(Yunlong Fm.in Lanping basin)are constituted by an alternation of salt layers and interbedded facies.The latter consists mainly of mudstones,and mudstone-rich conglomerate.The mineralogy and geochemistry of salt-bearing beds and
文摘Utility of geochemistry in mineral exploration is known since more than half-a-century.In reconnaissance diamond exploration,regolith geochemistry is a well known tool worldwide and helps in distinguishing bedrock
文摘Qarhan Salt Lake is located in the eastern part of the Qaidam Basin,which is first discovered the large potash deposit in the late 1950s.The Bieletan section is located in the west of Qarhan Salt Lake,where saline sediment
文摘1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
基金supported by the Special Scientific Research Fund of Public Welfare Profession of Ministry of Land and Resources of the People’s Republic of China (No. 201011057)
文摘1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich information on
文摘Field and geochemical studies of the Bunu area,SW Nigeria,were carried out on gneiss-metasedimentary rocks that consist of migmatised gneiss,quartz-mica schist,and foliated and massive quartzites.These gneissmetasedimentary rocks are interbedded with meta-igneous rock(amphibolite),all of which are intruded by granitoid and cut by basic and felsic dykes.Geochemical data on major,trace,and rare Earth elements of these rocks from the area were used to speculate on the petrogenetic and geodynamic evolution of the rocks in the area.Compositionally,the metasedimentary rocks in the area have a restricted range of major oxides such as SiO_(2)and Al_(2)O_(3)with low average values of FeO,MnO,CaO,and PO.Concentrations of average values of HSFE such as Zr,Nb,and Y are moderately high in migmatitic gneiss,quartzmica schist,and low in both massive and foliated quartzite.ΣLREE average values are 124.25,132.41,and18.64 ppm respectively for migmatite gneiss,quartz-mica schist,and low in both massive and foliated quartzite.These rocks are also generally enriched in Ba,Cs,Pb,U,Cr,Rb,and Zr and depleted in Be,Sr,Ti,Mo,Th,and W.This enrichment–depletion in major oxides and trace elements of the rocks in this area is probably a consequence of the movement of metamorphic remobilized fluids within the rocks in the area during the Pan-African or earlier events as noted in the adjacent Egbe-Isanlu Schist belt.A further geochemical characterisation of the rocks in the area using Log(Na_(2)O/KO)vs Log(SiO_(2)/Al_(2)O_(3)indicates that while the protolith of migmatised gneiss and quartzmica schist are greywackes to litharenite in compositions that of quartzites are sublitharenite to quartz arenite.On the ternary plot of Al_(2)O_(3)-(CaO+Na_(2)O)-KO for metasedimentary rocks in the area,most migmatitic gneiss and quartz-mica schist rocks plot close to average shale while quartzites mostly tend to illite compositions and almost toward the Al_(2)O_(3)-apex of the diagram attesting to depletion of CaO and Na_(2)O with the removal of KO.CIA vs PIA plot of the rocks in the area shows that while migmatitic-gneiss and quartz-mica schist are moderately weathered,both massive and foliated quartzites are high to extremely weathered.They are all derived mostly from predominantly felsic igneous to quartzose sedimentary provenance and mostly emplaced in passive continental margins.These nature of the protoliths suggests gradual subsidence of the basin during its genesis,and/or tectonic stable or inactive environment from which the sediments were derived.
文摘Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation（FGD）-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the p H and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the p H value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2 Se, and HAs O2 are the aqueous complexes with the highest activities under acidic conditions.The speciation of Zn, Li, and Ni is not affected in spite of p H changes; these elements occur as free cations and associated to SO4 ^2 in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the p H of the FGD-gypsum leachates, which might be associated to the precipitation of Cu Se2 and Mo Se2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.
