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1.
The Tomtor massif of Paleozoic ultramafic alkaline rocks and carbonatites is located in the northern part of the Sakha Republic (Yakutia). The massif (its total area is ~ 250 km2) is ~ 20 km in diameter, with a rounded shape and a concentrically zoned structure. The core of the massif consists of carbonatites surrounded by a discontinuous ring of ultramafic rocks and foidolites. The outer part is composed of alkali and nepheline syenites. All rocks are weathered and covered with eluvium, which is the thickest after carbonatites enriched in phosphates and REE. The weathering profile consists of four layers, from the top: kaolinite-crandallite, siderite, goethite, and francolite. The highest-grade ores are observed in the bedded deposit which fills depressions in “sagging” eluvium. The ores are laminated and cryptogranular, with high Nb, Y, Sc, and REE contents (on average, 4.5% Nb2O5, 7-10% REE2O3, 0.75% Y2O3, and 0.06% Sc2O3). The highest-grade ores are natural Nb and REE concentrates. The total REE content in some layers is > 10%. The morphologic features of the highest-grade phosphate ores from the northern part of the Burannyi site were studied. The ore-forming minerals belong to the pyrochlore group, crandallite group (goyazite), and monazite-Ce. The pyrochlore group minerals occur mainly as crystals that were completely replaced by barium-strontium pyrochlore and/or plumbopyrochlore but retained the original faces; also, they occur as numerous conchoidal fragments. The grains of the pyrochlore group minerals sometimes have a zonal structure, with an unaltered pyrochlore core and a reaction rim. Goyazite occurs predominantly as colloform grains. According to SEM and TEM data, monazite occurs in the ores as ~ 50 nm particles, which cover the outer part of halloysite tubes (800–3000 nm long and 300 nm in diameter) as a dense layer and make up peculiar biomorphic aggregates. The mineralogical data, the occurrence of biomorphic aggregates, and the close association of organic remains with ore minerals suggest that the high-grade ores of the Tomtor deposit, including the Burannyi site, resulted from a hydrothermal-sedimentary process with a presumably important role of bioaccumulation of REE phosphates.  相似文献   

2.
The Shazi anatase ore deposit in Qinglong, Guizhou Province, is a large-sized anatase deposit that has been recently explored. The characteristics of major oxides in the ore are similar to those of modem laterite weath- ering crust and laterite in the laterite-type gold deposits in the western part of Guizhou Province. Studies on the REE characteristics of basalts and anatase ores in the study region showed that both of them do have extremely strong affinities. There are two groups of trace elements in the ores, i.e., Au-Ag-As-Sb-Hg-Tl association and Sc-TiO2-Cu-Fe-Mn association, reflecting that the formation of anatase ore is related to the formation of siliceous claystone at the early stage of eruption of the Emeishan basaltic magma. The siliceous claystones are the major country rocks for the formation of laterite-type gold ores and anatase ores. In the region anatase ores are rich in Sc and the basalts enriched in Fe, Mn, Ti and Sc are the material source of metallogenesis.  相似文献   

3.
The Snezhnoe phenakite-beryl deposit is one of the highest-grade deposits in the Altai-Sayan beryllium province. This deposit is spatially associated with the alkali granite of the Ognit Complex and localized in the apical part of the granitic pluton. The trace element composition of granite, as well as of Be and Ta-Nb ores was studied. The Rb-Sr age of Be mineralization estimated at 305 Ma is consistent with the time of formation of numerous rare-metal alkali granitic plutons in the Eastern Sayan and the eastern Tuva. The region of these granitic plutons is outlined as the Late Paleozoic East Sayan rare-metal metallogenic zone specialized for Nb, Ta, Be, Li, Zr, Th, and REE mineralization. The East Sayan zone is localized in the marginal part of the Barguzin igneous province and is similar to the marginal zone of this province in composition of igneous associations and metallogenic specialization. The formation of the Barguzin igneous province and the East Sayan metallogenic zone is related to the evolution of the Late Carboniferous-Early Permian mantle plume.  相似文献   

4.
“寨背式”离子吸附型稀土矿床多类型稀土矿化及其成因   总被引：1，自引：0，他引：1  
赵芝  王登红  邹新勇 《岩石学报》2022,38(2):356-370
赣南寨背离子吸附型稀土矿床产于寨背复式花岗岩体的风化壳中,自20世纪80年代发现以来一直以轻稀土型开采,近年在轻稀土型花岗岩风化壳中发现了重稀土矿。为了探讨轻稀土型花岗岩风化过程中重稀土元素的迁移、分馏和富集机制,本文选择了区内三个具有代表性的风化壳钻孔(ZK1、ZK2和ZK4)对其进行了全相和离子交换相稀土元素地球化学研究。结果显示：钻孔ZK4中离子交换相稀土含量介于14.90×10-6～835.8×10-6之间,并富集轻稀土(LREE/HREE=2.28～10.78);钻孔ZK1中离子交换相稀土含量达1470×10-6(9件样品均值),具有从轻稀土型向重稀土型过渡的配分特征(LREE/HREE=1.30～1.65),并且剖面自上而下显示轻、重稀土逐渐富集的趋势;钻孔ZK2中离子交换相稀土含量为492.4×10-6(8件样品均值),自上而下稀土配分类型从轻稀土型过渡至重稀土型(LREE/HREE=0.43～2.25),且轻稀土富集在全风化层上部而重稀土则富集在下部。三个钻孔的Nb/Ta和Zr/Hf...  相似文献   

5.
The Katugin deposit of economic Ta, Nb, Zr, U, REE, Y, and cryolite (Na3AlF6) ores is located in the Kalar district of the Chita region and classified as unique in Nb, Ta, and Y reserves hosted in rare-metal alkali granite. The distribution of trace elements (including REE) in zircon was studied for ore-bearing arfvedsonite–aegirine, biotite–riebeckite rocks, and zones of late recrystallization with nodular zircon clusters. The outer rims and marginal zones of zircon grains are depleted in almost all trace elements except for hafnium as compared with cores and central zones. Compositional features of zircon cores indicate their magmatic origin and do not prove metasomatic nature of the deposit. The similar REE patterns of zircon rims and cores, as well as other attributes assume postmagmatic or metamorphic origin of the rims.  相似文献   

6.
The present study focuses on the Late Cretaceous Bidgol bauxite deposit in the Zagros Simply Fold Belt, SW Iran. The orebody is located in the eroded major NW–SE trending Koh-e-Hosseyn anticline and hosted as discontinuous stratified layers and lenses within the upper member of the Cenomanian–Turonian Sarvak Formation. Detailed mineralogical analysis reveals that diaspore, hematite, goethite, anatase, clinochlore, chamosite, and calcite are the major mineral components accompanied by minor amounts of detrital and REE-bearing minerals such as rutile, zircon and parisite. The ore texture suggest that the bauxite material has an authigenic origin but in some parts it has been transported short distances from a primary in situ environment and redeposited in karstic depressions. The spheroidal pisolites of the Bidgol bauxite formed under conditions of low water activity, favouring the formation of large diaspore cores and a single dry-to-wet climatic fluctuation. The mass change calculations relative to the immobile element Ti show that elements such as Si, Fe, Mg, K, Na and Sr are leached out of the weathered system; Al, Ni, Zr, Ga, Cr and Ba are concentrated in the residual system; and Hf, Ta, Co, Rb, Cs, Be, and U are relatively immobile during the bauxitisation processes. The Nb, Th, Y, V, Sc, Sn and ΣREE are relatively immobile in the initial stage of bauxitisation processes in the bauxite ores, but were slightly mobile at the later stage of bauxitisation. Geochemical data reveal progressive enrichment of the REE and intense LREE/HREE fractionation toward the lower parts of the bauxite profile. Cerium behaves differently from the other REEs (especially LREE) and show positive anomalies in the upper horizons that gradually become negative in the deeper parts of the profile. The distribution and fractionation of trace elements and REEs during the bauxitisation process in the Bidgol deposit are mainly controlled by the presence of REE-bearing minerals, fluctuations in soil solution pH, REE ionization potential and the presence of bicarbonates or organic matter. Geochemical analyses confirm a protolith contribution from the bedrock argillaceous limestone and suggest that the source material for the Bidgol bauxite was provided from a siliciclastic material derived from a continental margin. The mid-Turonian uplift led to the formation of karstic topography, rubbly breccia and a layer of ferruginous–argillaceous debris that was affected by lateritic weathering under humid tropical climate. Subsequently, mobile elements are removed from the profiles, while Al, Fe and Ti are enriched, resulting in the formation of the pristine bauxite materials. When the platform subsided into the water again, the pristine bauxitic materials were partly converted to bauxite. During the exposure of bauxite orebodies on the limbs and crests of anticlines and subsequent eroding and accumulation in the karstic depressions during folding and faulting in Oligocene–Miocene, important factors such as intensity of the weathering, drainage and floating flow may have improved the qualities of the bauxite ores.  相似文献   

7.
东坪金矿床成矿过程中稀土元素活动性   总被引：8，自引：2，他引：6  
尽管稀土元素常被认为是惰性元素,但在热液交代蚀变和化学风化作用过程中具有一定程度的活动性,河北省东坪与碱性岩有关的改进改造型热液金矿床成矿过程中,热液蚀变作用使近矿围岩ＬＲＥＥ／ＨＲＥＥ比值增大,并出现现铈正常异常;石英脉型金矿石的稀土元素分布模式呈出现明显的继承性,脉石矿物石英,钾长石的稀土元素组成相对富ＨＲＥＥ,且在脉石石英出现明显的铕正异常,研究结果表明在中,高温,近中性,较高氧逸度成矿流体  相似文献   

8.
浙江八面山萤石矿床稀土元素地球化学特征及成因探讨   总被引：4，自引：2，他引：2  
对浙江八面山萤石矿床中不同类型萤石矿石和围岩样品的稀土元素的系统分析表明,细粒萤石矿石的ΣREE〈39×10-6,LREE为14.36×10-6～34.24×10-6,HREE0.96×10-6～2.04×10-6,Y〈3×10-6;巨晶萤石矿石中的ΣREE3.62×10-6～20.81×10-6,LREE2.71×10-6～17.67×10-6,HREE0.24×10-6～1.49×10-6;而围岩花岗岩的ΣREE460.29×10-6,LREE225.97×10-6,HREE91.32×10-6,Y＆gt;140×10-6;沉积岩中的ΣREE20.22×10-6、LREE16.11×10-6、HREE1.61×10-6。矿石与围岩中沉积岩的稀土总量、轻稀土、重稀土和Y的含量接近,与花岗岩的稀土总量、轻稀土、重稀土和Y元素含量相差悬殊。萤石矿石的稀土分布型式主要为轻稀土富集型,（La/Yb）N通常多数大于8,在8.07～17.26间,δEu值在0.45～1.30,δCe在0.89～1.14间,Ce、Eu基本不显异常。矿石与围岩的稀土地球化学研究显示,八面山萤石矿床为受地层、岩体与断裂共同控制＂三位一体＂的低温热液型矿床。  相似文献   

9.
The Burpala alkaline massif is a unique geological object. More than 50 Zr, Nb, Ti, Th, Be, and REE minerals have been identified in rare-metal syenite of this massif. Their contents often reach tens of percent, and concentrations of rare elements in rocks are as high as 3.6% REE, 4% Zr, 0.5% Y, 0.5% Nb, 0.5% Th, and 0.1% U. Geological and geochemical data show that all rocks in the Burpala massif are derivatives of alkaline magma initially enriched in rare elements. These rocks vary in composition from shonkinite, melanocratic syenite, nepheline and alkali syenites to alaskite and alkali granite. The extreme products of magma fractionation are rare-metal pegmatites, apatite-fluorite rocks, and carbonatites. The primary melts were related to the enriched EM-2 mantle source. The U-Pb zircon ages of pulaskite (main intrusive phase) and rare-metal syenite (vein phase) are estimated at 294 ± 1 and 283 ± 8 Ma, respectively. The massif was formed as a result of impact of the mantle plume on the active continental margin of the Siberian paleocontinent.  相似文献   

10.
REE mobility during hydrothermal ore-forming processes has been extensively investigated in recent years and the potential of REE to provide information about ore forming processes has commonly been recognized.The Dongping gold deposit,which is located in northwestern Hebei Province,China,occurring in the inner contact zone of the Shuiquangou syenite complex,is spatially,and probably genetically,related to the syenite,the deposit was formed under the moderate to high temperature(220℃ to 320℃),weakly acidic to weakly alkaline,rather high fo2(lgfo2=-30～-34)environment.The REE study of the host rocks,altered wall rocks,ores and gangue minerals from the deposit suggests that the REEs have been mobilized and differentiated during K-feldspathization and silicification.The extremely altered syenite enveloping auriferous quartz vein shows positive Ce anomaly and larger LREE/HREE ratio than that of the unaltered syenite.The REE concentrations and patterns of the ores are determined by the ore types and mineral assemblages,LREE/HREE ratios in the gangue quartz and hydrothermal Kfeldspars are relatively low.The most significant observation is that the gangue quartz shows significant positive Eu anomaly,whereas the hydrothermal K-feldspars show less significant or no positive Eu anomaly at all relative to the primary feldspar in the unaltered syenite. It is evident that the REEs are mobile during K-feldspathization and silicification in the ore forming process.Weak to moderate K-feldspathization caused REE mobility without apparent differentiation with the exception of extreme K-feldspathization and silicification which resulted in significant depletion of HREE and Eu and relative enrichment of Ce.The REE,Y,U,Th and Au contents of the syenite decrease as the degrees of K-feldspathization and silicification of the rocks increase towards the auriferous quartz veins.As the ores were deposited under a rather oxidized environment,Ce^4 predominated over Ce^3 .The precipitation of the former in the form of CeO2 or absorpted onto the secondary mineral assemblage resulted in the inconsistent removal of the REE and the relative Ce enrichment in the strongly altered rocks.in contrast,Eu was present mainly in a low valence state (Eu^2 ).The geochemical differences from the other REE^3 and much less sites in the secondary minerals to accommodate the Eu released form the original minerals resulted in the enrichment of Eu in the fluids.The mobility and differentiation of REE and the coherent mobilities of Y,U,Th and Au also support the argument that the syenite is one of the source rocks for gold mineralization.The REE contents and patterns of the altered rocks enveloping the auriferous quartz vein could be used as a guide for locating ore veins in mineral exploration.  相似文献   

11.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＹｉｎｓｈａｎｄｅｐｏｓｉｔｉｎｔｈｅｎｏｒｔｈｅａｓｔｅｒｎＪｉａｎｇｘｉＰｒｏｖｉｎｃｅｏｆＣｈｉｎａｉｓａｌａｒｇｅ ｓｕｐｅｒｌａｒｇｅｐｏｌｙｍｅｔａｌｌｉｃＣｕ Ｚｎ Ｐｂ Ａｇ Ａｕｄｅ ｐｏｓｉｔ.Ｔｈｏｕｇｈｔｈｅｒｅａｒｅｍａｎｙｄｉｆｆｅｒｅｎｔａｒｇｕｍｅｎｔｓａｂｏｕｔｔｈｅｇｅｎｅｓｅｓｏｆｔｈｅｄｅｐｏｓｉｔ(Ｈａｏ ,1998;Ｚｈａｎｇ ,1997;ＪｉａｎｇｘｉＧｅｏ ｌｏｇｉｃＥｘｐｌｏｒａｔｉｏｎＢｕｒｅａｕ ,1996 ;Ｚｈａｎｇ ,1996 ;Ｈｕａ ,1987;Ｙ…  相似文献   

12.
Doklady Earth Sciences - Among the rich REE–Nb ores of the upper ore horizon of the Tomtor deposit, under the Jurassic deposits (borehole 324, interval 47–62 m), ultrapotassiс...  相似文献   

13.
Mineralization with ion adsorption rare earth elements (REEs) in the weathering profile of granitoid rocks from Nanling region of Southeast China is an important REE resource, especially for heavy REE (HREE) and Y. However, the Jurassic granites in Zhaibei which host the ion adsorption light REE (LREE) ores are rare. It is of peraluminous and high K calc-alkaline composition, which has similar geochemical features of high K2O + Na2O and Zr + Nb + Ce + Y contents and Ga/Al ratio to A-type granite. Based on the chemical discrimination criteria of Eby [Geology 20 (1992) 641], the Zhaibei granite belongs to A1-type and has similar source to ocean island basalts. The rock is enriched in LREE and contains abundant REE minerals including LREE-phosphates and halides. Minor LREE was also determined in the feldspar and biotite, which shows negligible and negative Eu anomalies, respectively. This indicates that the Zhaibei granite was generated by extreme differentiation of basaltic parent magmas. In contrast, granites associated with ion adsorption HREE ores contain amounts of HREE minerals, and show similar geochemical characteristics with fractionated felsic granites. Note that most Jurassic granitoids in the Nanling region contain no REE minerals and cannot produce REE mineralization. They belong to unfractionated M-, I- and S-type granites. Therefore, accumulation of REE in the weathering profile is controlled by primary REE mineral compositions in the granitoids. Intense fractional crystallization plays a role on REE enrichment in the Nanling granitoid rocks.  相似文献   

14.
宁夏卫宁北山地区划属北祁连成矿带之宁夏香山-卫宁北山-固原铜、金、铁、铅锌多金属成矿带,铜、金、铁多金属成矿作用显著。金矿体主要以似层状、透镜状产出,受断裂破碎带控制。矿石大部分为氧化矿石,少许为原生硫化物矿石。金矿床岩石稀土总量变化较大(∑REE=12.04×10~-6～136.167×10~-6),轻稀土富集,重稀土亏损;La/Yb值为0.609～16.158,Sm/Nd值为0.18～0.275,表明轻重稀土发生一定程度的分馏;δEu=0.447～0.91,表现为Eu的亏损。研究认为:金场子金矿应属于沉积-构造-热液改造型金矿,其形成受地层、岩性、构造控制,但成矿作用主要与石英闪长玢岩侵入有关,主要发生了黄铁矿化、高岭土化、黄钾铁矾化和硅化,后期经历了较强烈的氧化淋滤作用,对该矿床的形成具有非常重要的意义。  相似文献   

15.
The paper presents detailed geochemical data on the rocks of the Zashikhinsky Massif and mineralogical–geochemical characteristics of the ores of the eponymous deposit. The rare-metal granites are divided into three facies varieties on the basis of the degree of differentiation and ore potential: early facies represented by microcline–albite granites with arfvedsonite, middle facies represented by leucocratic albite–microcline granites, and late (most ore-bearing) facies represented by quartz–albite granites grading into albitites. Microprobe data were obtained on major minerals accumulating trace elements in the rocks and ores. All facies of the rare-metal granites, including the rocks of the fluorite–rare-metal vein, define single compositional trends in the plots of paired correlations of rock-forming and trace elements. In addition, they also show similar REE patterns and spidergrams. The latter, however, differ in the depth of anomalies of some elements. Obtained geological, petrographic, and geochemical data suggest a magmatic genesis of the rocks of different composition and their derivation from a single magma during its differentiation. On the basis of all characteristics, the Zashikhinskoe deposit is estimated as one of the largest tantalum rare-metal deposits of alkaline-granite type in Russia.  相似文献   

16.
相山铀矿田的成矿流体性质和来源存在争议,为进一步探讨相山铀矿田成矿流体的性质和来源,本文对相山铀矿田西部的居隆庵铀矿床和北部的沙洲铀矿床中的新鲜围岩、蚀变围岩及矿石的微量、稀土元素含量及其变化进行了研究。结果显示:在含较多热液成因萤石的居隆庵铀矿床中,从新鲜围岩到蚀变围岩到矿石,Zr、Hf含量先降低再升高;而在含少量热液萤石的沙洲铀矿床中,新鲜围岩、蚀变围岩和矿石的Zr、Hf含量基本一致。鉴于富F流体易汲取岩石中的Zr、Hf,因此,这两个矿床中不同类型样品Zr、Hf含量的不同变化趋势,可能与居隆庵铀矿床的成矿流体富F、而沙洲铀矿床的成矿流体相对贫F有关。这两个铀矿床中矿石的稀土配分曲线与其各自的新鲜及蚀变围岩的稀土配分曲线形态相似但又存在差异,说明每个矿床的新鲜围岩、蚀变围岩和矿石之间的稀土元素既具有继承性、又受到不同性质的流体的影响。居隆庵铀矿床中矿石显示Eu负异常,可能主要是继承了围岩的Eu负异常;沙洲铀矿床中矿石Eu显示弱负异常至弱正异常的特征,可能与围岩中斜长石因热液蚀变作用而释放出的Eu的进入流体有关。基于新鲜围岩、蚀变围岩及矿石的U和REE研究,推断居隆庵铀矿床成矿流体中U和REE均以F的络合物形式迁移;但沙洲铀矿床中铀矿石品位较低,可能是与流体中相对贫F有关。  相似文献   

17.
湖南沃溪金-锑-钨矿床成因的稀土元素地球化学证据   总被引：11，自引：0，他引：11  
沃溪金-锑-钨矿床的稀土元素地球化学组成良好地反映了成矿作用的条件和过程,并为示踪矿床成因提供了有用的信息.以流体包裹体为代表的成矿溶液,以较高的稀土总量、显著的轻稀土富集和缺乏明显的铕异常为特征,代表了一种通过在碎屑沉积物柱中循环而萃取矿质的演化的海水热液.矿石相对于成矿流体(母液)富集重稀土而轻微亏损铕,反映了矿石沉淀过程中来自于海水的稀土元素掺合.同一矿层内由下往上,重稀土相对富集的程度逐渐增大而稀土总量则逐渐降低,表明随着热液化学沉淀作用的进行,海水掺合的影响逐渐增强.矿石的稀土元素组成,无论在分布模式还是在轻重稀土之间的分馏程度上,均与其他许多 Sedex型多金属矿床十分相似,暗示了这些矿床具有相似的成因机制.稀土元素地球化学特征支持矿床同生沉积成因的观点.  相似文献   

18.
Most of the karstic bauxite deposits in China are enriched in REE, and the REE has commonly been considered to be adsorbed on the surface of clay or diaspore minerals as ion state. However, occurrence of REE minerals in the bauxite deposits has not been reported by far. In the Quyang bauxite deposit from Guangxi province, we find REE minerals. The minerals are parisite and churchite. Parisite is widely distributed in the ooids and matrix, inducing positive Ce anomaly of the ores; whereas, churchite is rare and occurred in the core of ooid. The compositions of the REE minerals show the Eu anomaly can change gently during the weathering, and the Eu anomaly analyses suggest that the REE in the ores are mostly derived from the underlying carbonates. The parisite is formed in an alkaline condition, while churchite in an acidic situation; the co-existence of the two minerals in the ores suggests the Permian environment for bauxite formation is complex with great change of pH value. Moreover, parisite is inferred to be formed earlier than the churchite.  相似文献   

19.
李莹  何保  滕寿仁  邓颖 《矿物岩石》2019,39(1):74-81
为探讨辽宁大台沟铁矿床的成矿物质来源及形成环境,选取典型铁矿石5块进行主量元素、微量元素和稀土元素分析测试。结果显示:大台沟铁矿床保存有明显的化学沉积特征,化学成分主要由Fe_2O_3,FeO和SiO_2组成(Fe_2O_3+FeO+SiO_2=87.33%～96%),其他组分(MnO,MgO,CaO,Na_2O,K_2O,TiO_2,P_2O_5,Al_2O_3)含量较低;页岩标准化后的稀土元素配分曲线显示为稀土总量低(ΣREE平均为19.65×10-6),轻稀土元素相对亏损,重稀土元素相对富集;且具有一定的Eu(Eu/Eu~*=1.52～2.72),Y(Y/Y~*=1.18～1.52),La(La/La~*=1.17～2.26)的正异常,弱的Ce(Ce/Ce~*=0.79～0.92)异常;Y/Ho值平均34.19接近于海水的分布范围;Sr/Ba值平均1.79,属于火山岩和海相沉积物;Ti/V值平均38.84,属于火山建造。这些特征表明:该矿床的形成可能与海相火山沉积物有关,属于火山沉积变质型铁矿范围;成矿物质来源于热水和海水的混合作用;矿床形成于相对于缺氧的环境。  相似文献   

20.
A detailed study of the florencite and xenotime assemblage from quartz veins of Au-REE occurrences in the Subpolar Urals allowed the REE fractionation and distribution of REE mixtures in the crystal structure to be characterized. In minerals of selective composition, isomorphic mixtures of LREE and HREE are divided into lanthanum Lasg (La-Pr) and samarium Smsg (Nd-Eu) subgroups in florencite and gadolinium Gdsg (Gd-Dy) and ytterbium Ybsg (Ho-Lu) subgroups in xenotime. Concentrations of elements from these subgroups are inversely proportional to each other. Each florencite or xenotime crystal is characterized by several mineral varieties: xenotime-(Y) and Gd-bearing xenotime-(Y), florencite-(Sm), -(Nd), and -(Ce); they are selectively distributed by growth zones and pyramids of the crystal with formation of direct and inverse zoning. In both cases, cores of the crystals are enriched in HREE. The correlation between REEs, Y, and such trace elements as As, S, Ca, Sr, U, and Sc is established. REE deportment is considered in minerals formed as products of primary crystallization and hydrothermal redeposition. The REE fractionation is interpreted in terms of quantum mechanics.  相似文献   

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