Mechanism of Formation of Premian Volcanic Rocks in Sawu''er Region,Xinjiang, China: Constraints from Rare Earth Elements

A large quantity of Premian volcanic rocks formed in Sawu'er region of Xinjiang, China. Based on the analysis of the rare earth elements' (REEs) geochemical characteristics of the volcanic rocks, the correlativity of REE and major elements, and diagrams of covariant relation of REE, combined with the research results of the regional geological setting,petrology, and petrochemistry characteristics, it is inferred that the mechanism of the formation of Premian basic and intermediate volcanic rocks is mainly attributed to equilibrium partial melting, and the magmatic fractional crystallization is not significant, whereas the rock-forming processes of medium-acidic volcanic rocks is influenced by both partial melting and fractional crystallization. The REE geochemical research provided important evidence for the mechanism of magmatism of the Premian post-collision stage and the geodynamical evolution process.     

Mechanism of Formation of Premian Volcanic Rocks in Sawu＇er Region, Xinjiang, China： Constraints from Rare Earth Elements

A large quantity of Premian volcanic rocks formed in Sawu＇er region of Xinjiang, China. Based on the analysis of the rare earth elements＇ （REEs） geochemical characteristics of the volcanic rocks, the correlativity of REE and major elements, and diagrams of covariant relation of REE, combined with the research results of the regional geological setting, petrology, and petrochemistry characteristics, it is inferred that the mechanism of the formation of Premian basic and intermediate volcanic rocks is mainly attributed to equilibrium partial melting, and the magmatic fractional crystallization is not significant, whereas the rock-forming processes of medium-acidic volcanic rocks is influenced by both partial melting and fractional crystallization. The REE geochemical research provided important evidence for the mechanism of magmatism of the Premian post-collision stage and the geodynamical evolution process.     

Enrichment and Release of Rare Earth Elements during Weathering of Sedimentary Rocks in Wujiang Catchments

Thirteen weathering profiles of sedimentary rocks such as limestone, dolomitic limestone, dolomite, silicalite, black shale and purple sandrock from Wujiang catchments were selected for study on enrichment and release behavior of rare earth elements （REE） during weathering, and in its impact on plant growth and riverine REE distribution in the catchments with methods of hierachical cluster analysis and mass balance calculation in order to set a basis for riverine material source research and agricultural production. The results show that the enrichment degree of REE in calcareous soils from the Wujiang catchments is much higher than that of limestone, yellow soil, upper continental crust （UCC）,     

Geochemical Characteristics of Rare Earth Elements in Gejiu Tin Polymetallic Deposits, Yunnan Province, China

In order to get a better understanding of metallogeny, the geochemical characteristics of REE and trace element for Gejiu tin polymetallic deposits were studied by comparing concentrations of REE and trace elements in different type ores and rocks, including skarn-type ore, bedded-type ore, vein-type ore, altered granite, country rocks. Results of this study indicated that the metallogenic matters for different type ores in the study area might be derived from the same origin source, which may be mainly related to granitic activities. Furthermore, there are some differences in concentrations of REE in different ores due to their different depositiona! mechanism during that time. LREE concentrations were enriched relatively in the vein-type ores and the bedded-type ores with relatively low total REE concentrations, whereas total REE concentrations were higher in the skarn-type ores with LREE and HREE concentrations in wide variation ranges.     

Effect of Long-term Intake of Rare Earth in Drinking Water on Trace Elements in Brains of Mice

Ｔｈｅｉｍｐａｃｔｏｆｒａｒｅｅａｒｔｈｓｏｎｅｎｖｉｒｏｎｍｅｎｔ,ｈｅａｌｔｈａｎｄｅｃｏｓｙｓｔｅｍ ,ａｎｄｉｔｓｌｏｎｇ ｔｅｒｍｂｉｏ ｌｏｇｉｃａｌｅｆｆｅｃｔｓｈａｖｅｄｒａｗｎｐｅｏｐｌｅ′ｓｍｕｃｈａｔｔｅｎ ｔｉｏｎ ,ｍａｎｙｗｏｒｋｓｈａｖｅｂｅｅｎｄｏｎｅ ,ｂｕｔｌｉｔｔｌｅｈａｓｋｎｏｗｎａｂｏｕｔｔｈｅｅｆｆｅｃｔｏｆｒａｒｅｅａｒｔｈｏｎｔｒａｃｅｅｌｅｍｅｎｔｓ[1 ] .Ｔｒａｃｅｅｌｅｍｅｎｔｓｐｌａｙａｎｉｍ ｐｏｒｔａｎｔｒｏｌｅｉｎｄｅｖｅｌｏｐｍｅｎｔ ,ｍｅｔａ…     

Geochemical Characteristics of Rare Earth Elements in Sewage Discharge Channels of Tianjin

The geochemical features of rare earth elements (REEs) in the North and South sewage discharge channels of Tianjin were studied. The results show that concentrations of dissolved REEs in water of the sewage discharge channels are very low, while concentrations of Eu and heavy REEs are higher than those in natural rivers. Concentrations of REEs in unfiltered water are high and they mainly resided on suspended matter. Distribution patterns of the dissolved and suspended light REEs vary reversely with the atomic number. Concentrations of REEs in the sediments and suspended matter are lower than those in natural rivers, and concentrations of REEs in the suspended matter are much lower than those in the sediments. Distrib.ution patterns of REEs in sediments and suspended matter were similar with light REE enrichment and positive Eu-anomaly. This distribution pattern is different from those of natural rivers. The differences may cause by the large amount of organic pollutants in sewage.     

Rare Earths, Trace Element Characteristics of High-Mg Volcanic Rocks of Yixian Formation in Sihetun West Liaoning Province and Its Apocalypse

The high-Mg volcanic rocks of the Yixian Formation in the Sihetun area have the obvious characteristics of mantle-derived lava in rare earth, trace element characteristics with high Mg# (62～70) and high content of compatible elements. In the meantime, the volcanic rocks also have the obvious characteristics of Crust-source material in rare earth, trace element characteristics with high ∑REE (158.78×10-6～359.66×10-6), high (La/Yb)N (14.61～29.60), high La/Nb(2.37～7.52) and high Ba/Nb(67.58～205.96), obvious positive anomaly of Pb and negative anomaly of Nb, Ta in trace element spider-gram. In Sr-Nd-Pb isotope the (87Sr/86Sr)i ratio is higher than 0.706 and the εNd(t) ratio is from -3.4 to -13, both reflect enriched Mantle characteristics. The characteristics above of the volcanic rocks combined with the content of Sr, Ba, Y, Yb and the ratio of Sr/Y show that the volcanic rocks have the property of the Sanukite rocks in Setouchi Japan beside subduction zone, and illuminate that the Sanukite rocks can be formed not only in island-arc near subduction zone but also in intro-plate. The analysis indicates that the high-Mg volcanic rocks in the Sihetun area result from the collective function of mantle-derived lava and crust-source materials. The result illuminates that the West Liaoning region is very special in tectonic geochemical background in Cretaceous in East China, and is an ideal region for us to further study the characteristics of magmatic activity as well as the process of Crust-Mantle interaction in Eastern China.     

Geochemical Characteristics of Rare Earth Elements in Intertidal Sediments of Tianjin Coastal Zone

Ｉｎｃｒｅａｓｉｎｇｕｓｅｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓ(ＲＥＥｓ)ｉｎｉｎｄｕｓｔｒｙａｎｄａｇｒｉｃｕｌｔｕｒｅｉｎＣｈｉｎａｈａｓｒｅｓｕｌｔｅｄｉｎｒｅｓｉｄｕｅａｎｄａｃｃｕｍｕｌａｔｉｏｎｉｎｒｉｖｅｒａｎｄｉｎｔｅｒｔｉｄａｌｚｏｎｅ ,ｈｅｎｃｅｉｔｗｏｕｌｄｃａｕｓｅｗａｔｅｒｐｏｌｌｕｔｉｏｎ ,ｗｈａｔａｒｅｔｈｅｇｅｏｃｈｅｍｉｓｔｒｙｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＲＥＥｓｉｎｖａｒｉｏｕｓｗａｔｅｒｂｏｄ ｉｅｓ ,ｉｔｉｓａｎｕｒｇｅｎｔｐｒｏｂｌｅｍｔｏｂｅｓｏ…     

Geochemical Characteristics and Behaviors of Rare Earth Elements in Process of Vertisol Development

Vertisol developed on argillaceous rocks has its special pedogenic processes and properties, and formed some secondary no,Jules. In study area, contents of rare earth elements (REE) are significantly different in different sedimentary rocks due to varied contents of clay fraction and clay mineral composition, etc. Under the dry and hot climate, REEs were less differentiated than their parent sedimentary rocks. However, REEs in secondary nodules formed in pedogenic process display their specific behaviors. They are more concentrated in iron concretions, the content of heavy REEs increases relatively, and positive Ce-anomaly appeares. But, negative Ceanomaly was found in calcium concretions, while normal Cecontent in parent recks and vertisol.     

Geochemistry of Rare Earth Elements in Aktishikan Gold Deposit,Xinjiang

The characteristics and the models of rare earth elements in the geological bodies and the hydrothermal water balancel with the adamellite were comprehensivealy studied in Aktishikan gold deposit,Nurt area of Altay,Xinjiang,And the behavior of rare earth elements during metasomatic alteration was discussed by using the isocon method of Grant,The results show that the rare earth elements are inert during metasomatic alteration,the hydrotheraml water has no relation to the magmatic water,and the gold material sources mainly stem from the wall rock.     

Geochemistry of Rare Earth Elements in Lamprophyres in Laowangzhai Gold Orefield, Yunnan Province

The super-large Laowangzhai gold ore deposit is situated in the northern Ailaoshan tectonic zone I Yunnan Province 9 and was foundat the end of 1980s. Lamprophyres are widelyspread over the orefield. The available datashow that the lamprophyres are tijmporally andspatially related to gold mineralization. In theorefield, lamprophyric dykes occur mainly along the main Northwest-Solltheast--strikingfaults and their subsidiary fractures and intruded into all the strata and magmatic rocks.Their …     

Rare Earths of Two Types Granites in Sawuer Region, Xinjiang

The geochemical characteristics of rare earth elements of A type and Ⅰ type granites were studied in the Sawuer region, Xinjiang. The characteristics of two types granites are different obviously,because the A type and Ⅰ type granites formed at different stage of the post-collisional period. The Sentasi intrusion and Wokensala intrusion are the Ⅰ type granites formed at the late of post-collisional period, and there is extrusion translating to extension stress. The characteristics of rare earth elements show that the fractional crystallization of the Ⅰ type granites is indistinct, and the sources of the Ⅰ type granites come from the mantle. The Kuoyitasi intrusion and Qiaqihai intrusion are the A type granites formed at the end of post-collisional period, and there is extension stress. The characteristics of rare earth elements show that the fractional crystallization of the A type granites is distinct. The sources of the A type granites come from the mantle but interfused by the crust.     

Effect of Rare Earth Elements on Isothermal Transformation and Microstructures in 20Mn Steel

The effect of rare earth elements on the isothermal transformation and microstructures in 20Mn steel is in-vestigated by means of metallography and dilatometry.Rare earth elements decrease both the incubation periodof pro-eutectoid ferrite and the rate of pearlitic transformation.In addition,rare earth elements play a role ofreducing needle-like ferrite and the amount of pearlite,densifing the lamellar space of pearlite and enhcingsegregation of carbide in granular bainite.It is suggested that rare earth elements may decrease the interfacialenergy of grain boundary and interphase,hinder the diffusion of carbon atoms and form rare earth carbides withhigh melting point which reduce the carbon content in austenite.     

Geochemistry of Rare Earth Elements in Xikeng Ag-Pb-Zn Ore Deposit, South Anhui, China

ＴｈｅＳｏｕｔｈＡｎｈｕｉｉｓｌｏｃａｔｅｄｉｎｔｈｅｌｏｗｅｒＹａｎｇｔｚｅＲｉｖｅｒｐｌａｔｆｏｒｍａｌｆｏｌｄｂｅｌｔｏｆｔｈｅＹａｎｇｔｚｅｐａｒａｐｌａｔｆｏｒｍｉｎＪｉａｎｇｎａｎ .Ａｌａｒｇｅ ｓｃａｌｅｔｒａｎｓｇｒｅｓｓｉｏｎｓｉｎｃｅｔｈｅｌａｔｅＳｉｎｉａｎａｆｔｅｒｅａｒｌｙＳｉｎｉａｎＮａｎｔｕｏｇｌａｃｉａｌｐｅｒｉｏｄｌｅｄａｂｌａｃｋｓｈａｌｅｆｏｒｍａｔｉｏｎｃｏｎｓｉｓｔｉｎｇｏｆｂｌａｃｋｃａｒｂｏｎａ ｃｅｏｕｓｓｈａｌｅ ,ｃａｒｂｏｎａｃｅｏｕｓｍｕｄｓｔ…     

Geochemistry of Rare Earth Elements of Mesozoic-Cenozoic Sandstones in North Margin of Dabie Mountains and Adjacent Areas： Constraints to Source Rocks

Mesozoic CenozoicdetritalrocksdevelopinthenorthmarginoftheDabieMountains ,andthestudyoftheirsourcerockshasattractedcloseattention .Sand stonecomponentsarecommonlyappliedinthestudyofstructuresettingofsourcerocks ,butitisdifficulttoconstructcorrespondingrelationsbetweensedimentanditssourcerocks[1～ 4 ] .Thepaper ,forthefirsttime ,studiesindetailREEgeochemistryofMesozoic CenozoicsandstonesinthenorthmarginoftheDabieMountainsandadjacentareas ,characterizesREEofeachstratigraphicunit ,suggeststh…     

Geochemical Study of Rare Earth Elements on Four Attapulgite Clay Deposits in Jiangsu and Anhui Provinces, China

This paper discussed in detail about the BEE component and the characteristics of the different kinds of attapulgite clay ores as well as basalts, weathered basalts in four localities of attapulgite clay deposits of Jiangsu and Anhui Provinces of China. It is concluded that the half-weathered basalts have not distinct REE fractionation and strong weathered basalts have HREE loss in the process of the basalts weathered to form smectite group minerals. And the latefitic montmorillonite clays that formed from the basalts weathering have a distinct Ce positive anomaly, a little MREE loss and LREE and HREE renew enrichment. That reflects the particular oxidation condition in the Earth‘‘ s surface and the adsorption of the colloid solution of the lake water in the basin of the continent in the time of the clays formed. The attapulgite clays produced by the reaction between basahs with lake water in the original place of the basin have same REE characteristics as that of the basalts and the weathered basahs. This shows that REE does not transfer heavily in the progressive chemical weathering process. The sedimentary attapulgite clays have also a similar REE component and characteristic parameters to the basalts and the weathered basalts, and have a distinct Eu negative anomaly and a big value of LREE/HREE, which shows that the sedimentary clay came from the weathered basalts, and BEE partitioning patterns characters of the clays are controlled by the residual material of the weathered basalts.     

Electronic Theoretical Study of the Interaction between Rare Earth Elements and Impurities at Grain Boundaries in Steel

Rareearths(RE)aresurfaceactiveelements ,theirapplicationsinmetalmaterialscanbesum marizedaspurification ,modificationandall oying[1～ 3 ] .Itisaveryattractivesubjectthattheinter actionofREelementswithlowmeltingpointimpuri tiesintheregionofGBs ,suchasP ,S ,As ,Sbandsoon .ResultsofexperimentsshowthatsegregationinGBsofasmallamountofREinsteelrestrainsharmfulimpuritiessuchasP ,S ,As ,Pb ,Sb ,tosegregateto wardsGBs ,soREelementscancleanseandenhanceGBs ,therebyimprovethehightemperatureducti…     

Rare Earth Elements Compositions and Genesis of Xinhua Large-Scale Phosphorite Deposit in Western Guizhou, China

Zhijin County in Western Guizhou is one of the most important production areas of phosphorites in China. In order to investigate genesis of the phosphorites, their REE compositions were analyzed by using inductively coupled plasma emission mass spectrometry (ICP-MS) method. For comparison, phosphorites from the Lower Cambrian black rock series in Southern China, such as Zunyi in Guizhou and Zhangjiajie in Hunan Province, were also analyzed. The analytical data show that: (1) Xinhua phosphorites possess a quite high and greatly varied total rare earth elements (ΣREE), which varying between 164.23×10-6 and 1395.01×10-6 with average of 642.54×10-6, remarkable differentiation between light (LREE) and heavy rare earth elements (HREE), and the ΣLREE/ΣHREE ratios varying between 5.04 and 6.52. The ΣREE and ΣLREE/ΣHREE ratios of the Zunyi and Zhangjiajie phosphorites are 156.69×10-6～637.41×10-6 with average of 431.75×10-6 and 3.17～6.95 with average of 4.37 respectively; (2) All the phosphorites from Xinhua, Zunyi and Zhangjiajie show remarkable negative Ce anomalies. Besides, the Xinhua phosphorites possess lower δCe, which varying between 0.26 and 0.53 with average of 0.35, while δCe of the Zunyi and Zhangjiajie phosphorites are 0.30～0.66 with average of 0.47, suggesting that all of the phosphorites are typical marine sediments deposited mainly in ancient peri-continental seas, and the depositional position of the Xinhua phosphorite might be deeper; (3) Most phosphorites from Xinhua, Zunyi and Zhangjiajie possess unremarkable positive Eu anomaly, and only a few of samples show obvious ones. The δEu varies between 0.98 and 2.4, suggesting that hot (>200 ℃) and strong reductive hydrothermal fluids might have been involved in genesis of the phosphorites; (4) The Xinhua phosphorite is relatively depleted in HREE, and LaN/NdN and δY of most samples are >1 and >1.5 respectively. Besides, there exists no correlation between δY and δCe, suggesting that the phosphorite was subjected to quite strong weathering and leaching processes, and catagenesis do not greatly modify its REE compositions.     

Rare Earths of Magmatic Rocks in Yanshanian Stage in Adjacent Region of Anhui and Jiangxi Provinces, Jiangnan Uplift

The geochemical characteristics of rare earth elements of magmatic rocks of Yanshanian stage were studied in the south of Anhui Province and northeast of Jiangxi Province, Jiangnan Uplift. The result shows that the magnmtic rocks of Yanshanian stage in the south of Anhui Province are the typical crust source type and those in the northeast of Jiangxi Province have the characteristics of mantle source type. So the polymetal deposits having relation to the magmatic rocks of Yanshanian stage in the northeast of Jiangxi Province were developed better than those in the south of Anhui Province. The research results of the rare earth elements are confirmed by the studies of geophysics, tectonic setting and stable isotope at the same time. It also indicates that the rare earth elements are the effective approach to tracing the material sources of magmatic rocks.