Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able ...Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able to quantitatively monitor the temporal and spatial variation of erosion intensity, compared with traditional approaches. The applications of REETM in studying of sediment differentiation law, erosion process evolution, determination of sediment sources and sedimentation investigations, and determination of prediction parameters, were reviewed. Some application limitations were summarized.展开更多
Although previous investigations of the trace elements in snow and ice from the Qinghai-Tibetan Plateau obtained interesting information about pollution from human activities on the plateau, most were based on traditi...Although previous investigations of the trace elements in snow and ice from the Qinghai-Tibetan Plateau obtained interesting information about pollution from human activities on the plateau, most were based on traditional acidification methods.To emphasize the influence of the different sample-preparation methods on the records of trace elements and rare earth elements, snow samples were collected from glaciers on the Qinghai-Tibetan Plateau in China and prepared using two methods: traditional acidification and total digestion. Concentrations of 18 trace elements(Al, Ti, Fe, Rb, Sr, Ba, V, Cr, Mn, Li,Cu, Co, Mo, Cs, Sb, Pb, Tl, and U), along with 14 rare earth elements(REEs: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb, and Lu), Y, and Th in the snow samples, were measured using inductively coupled plasma-sector field mass spectrometry(ICP-SFMS). The results showed that the mass fraction of the trace elements(defined as ratio of concentration in the acid-leachable fraction to that in the digested sample) such as Mo, Ti, Al, Rb, and V, varied from 0.06 to 0.5. The mass fraction of other trace elements varied from about 0.6 to more than 0.9; those of the REEs, Y, and Th varied from 0.34 to0.75. Lower mass fractions will lead to an overestimated contribution of other sources, especially human activities, and the underestimated fluxes of these trace elements(especially REEs, Y, and Th, as well as dust) if the REEs are used as the proxy for the crust dust. The two sample-preparation methods exhibited different REE normalized distribution patterns,REE ratios, and provenance-tracing results. The REE normalized distribution patterns and proxies in the digested samples are more reliable and integrated than those found in traditional acidification method for dust-provenance tracing.展开更多
Since 2011,certain advances have been made through the resource investigation,metallogenesis research,mining supervision and environmental protection of ion-adsorption type rare earth element (REE) deposit in South Ch...Since 2011,certain advances have been made through the resource investigation,metallogenesis research,mining supervision and environmental protection of ion-adsorption type rare earth element (REE) deposit in South China.Firstly,some progress has been made in REE prospecting in Jiangxi,Guangdong,Guangxi and Yunnan.REE deposits are not only found within the weathering crusts of granites and felsic volcanic rocks,but also within the weathering crusts of epimetamorphic rocks and basic magmatic rocks.Secondly,the methods of exploration,delineating ore bodies and calculation of reserves have been improved,which intuitively reflect the thickness,REE composition and value of weathering crust.Thirdly,the relationship between REEs and weathering degree and the rule of distribution,migration and enrichment of REEs in the weathering profile was summarized through the analysis of big data,which can predict the metallogenetic horizon of REEs.Fourthly,a method for quick,accurate and dynamic investigation of the REE deposit has been established by using high resolution remote sensing technology.Finally,the relation between the production status of REE mines and water pollution has been revealed based on long-term hydrochemical monitoring data of rivers and wells in mines and surrounding areas.展开更多
Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls ...Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amount increases with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4.3 and 5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amount. The new REE tracer method should be useful to future studying of erosion processes on slope lands.展开更多
The distribution characteristics of rare earth elements （REE） in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships bet...The distribution characteristics of rare earth elements （REE） in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships between ΣREE content andprovenance, hydrodynamics, grain size and mineral distribution in the Beibu Gulf showsthat terrestrial rocks control the ΣREE composition. Both weaker hydrodynamics andfiner grain size lead to a higher ΣREE content. Relative curves revealing therelationships between individual impact factors and ΣREE content were obtained fromthe combination of qualitative and quantitative analyses of the BP neural network,which trained the position of samples, gravel content, sand content, silt content, claycontent and clay mineral content. The results are consistent with those of thequantitative analysis. The self-learning algorithm is automatically determined andcalculated quantitatively. The impact of each factor on REEs and how each factorcontrols the ΣREE distribution is identified. Thus, environmental changes and thegeological evolution of the region can be inferred based on curve variation and the geological evolution of the region can be inferred based on curve variation and theactual situation. This method also provides useful theoretical guidance for the analysisof REE enrichment and dispersion.展开更多
基金supported by the National Key Technology R&D Program of China(2006BAC10B020,2008BAD98B08)
文摘Rare earth elements （REEs） have been proved ideal tracers for soil erosion and aggregation. REE tracer method （REETM） used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able to quantitatively monitor the temporal and spatial variation of erosion intensity, compared with traditional approaches. The applications of REETM in studying of sediment differentiation law, erosion process evolution, determination of sediment sources and sedimentation investigations, and determination of prediction parameters, were reviewed. Some application limitations were summarized.
基金supported by grants provided by the National Natural Science Foundation of China(Grant Nos.41276194,40771046,and 40601021)
文摘Although previous investigations of the trace elements in snow and ice from the Qinghai-Tibetan Plateau obtained interesting information about pollution from human activities on the plateau, most were based on traditional acidification methods.To emphasize the influence of the different sample-preparation methods on the records of trace elements and rare earth elements, snow samples were collected from glaciers on the Qinghai-Tibetan Plateau in China and prepared using two methods: traditional acidification and total digestion. Concentrations of 18 trace elements(Al, Ti, Fe, Rb, Sr, Ba, V, Cr, Mn, Li,Cu, Co, Mo, Cs, Sb, Pb, Tl, and U), along with 14 rare earth elements(REEs: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb, and Lu), Y, and Th in the snow samples, were measured using inductively coupled plasma-sector field mass spectrometry(ICP-SFMS). The results showed that the mass fraction of the trace elements(defined as ratio of concentration in the acid-leachable fraction to that in the digested sample) such as Mo, Ti, Al, Rb, and V, varied from 0.06 to 0.5. The mass fraction of other trace elements varied from about 0.6 to more than 0.9; those of the REEs, Y, and Th varied from 0.34 to0.75. Lower mass fractions will lead to an overestimated contribution of other sources, especially human activities, and the underestimated fluxes of these trace elements(especially REEs, Y, and Th, as well as dust) if the REEs are used as the proxy for the crust dust. The two sample-preparation methods exhibited different REE normalized distribution patterns,REE ratios, and provenance-tracing results. The REE normalized distribution patterns and proxies in the digested samples are more reliable and integrated than those found in traditional acidification method for dust-provenance tracing.
文摘Since 2011,certain advances have been made through the resource investigation,metallogenesis research,mining supervision and environmental protection of ion-adsorption type rare earth element (REE) deposit in South China.Firstly,some progress has been made in REE prospecting in Jiangxi,Guangdong,Guangxi and Yunnan.REE deposits are not only found within the weathering crusts of granites and felsic volcanic rocks,but also within the weathering crusts of epimetamorphic rocks and basic magmatic rocks.Secondly,the methods of exploration,delineating ore bodies and calculation of reserves have been improved,which intuitively reflect the thickness,REE composition and value of weathering crust.Thirdly,the relationship between REEs and weathering degree and the rule of distribution,migration and enrichment of REEs in the weathering profile was summarized through the analysis of big data,which can predict the metallogenetic horizon of REEs.Fourthly,a method for quick,accurate and dynamic investigation of the REE deposit has been established by using high resolution remote sensing technology.Finally,the relation between the production status of REE mines and water pollution has been revealed based on long-term hydrochemical monitoring data of rivers and wells in mines and surrounding areas.
文摘Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amount increases with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4.3 and 5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amount. The new REE tracer method should be useful to future studying of erosion processes on slope lands.
文摘The distribution characteristics of rare earth elements （REE） in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships between ΣREE content andprovenance, hydrodynamics, grain size and mineral distribution in the Beibu Gulf showsthat terrestrial rocks control the ΣREE composition. Both weaker hydrodynamics andfiner grain size lead to a higher ΣREE content. Relative curves revealing therelationships between individual impact factors and ΣREE content were obtained fromthe combination of qualitative and quantitative analyses of the BP neural network,which trained the position of samples, gravel content, sand content, silt content, claycontent and clay mineral content. The results are consistent with those of thequantitative analysis. The self-learning algorithm is automatically determined andcalculated quantitatively. The impact of each factor on REEs and how each factorcontrols the ΣREE distribution is identified. Thus, environmental changes and thegeological evolution of the region can be inferred based on curve variation and the geological evolution of the region can be inferred based on curve variation and theactual situation. This method also provides useful theoretical guidance for the analysisof REE enrichment and dispersion.
