Rare earth elements in a sampled coal from the Pirin deposit,Bulgaria

Rare earth elements (La, Ce, Sm, Eu, Tb, Yb, and Lu) in a columnar section of the coal of the Pirin deposit, Bulgaria, have been determined by neutron activation analyses.The REE content in the coals is lower than the average REE content of shales from North America, Europe, and the Soviet Union. The REE abundances increase with the increasing ash content of the coals. The bottom of the seam is slightly enriched in REE, the trend being more pronounced in HREE (Tb, Yb, Lu). The REE content depends on the thickness of the coal layers: the thin coal layers are enriched in REE as compared to the thick ones.The chondrite-normalized distribution patterns are very uniform. They are characterized by a negative Eu anomaly whose mean value is 0.30 (varying in the individual samples from 0.21 to 0.49) and a positive Lu anomaly. It is supposed that the Eu anomaly is inherited from the source rocks.The shale-normalized distribution patterns show a distinct relative enrichment in HREE and a negative Eu anomaly. The relative enrichment in HREE is a specific feature of the REE geochemistry in the Pirin deposit. The LREE/HREE ratio is lower than that of composite shale; it increases with the increasing ash content of the coals and from the bottom to the top of the coal bed.REE are bound predominantly to the aluminosilicates of the mineral matter in the coals. All REE are positively correlated to the ash, Si, Al, Fe, and Na.The source of REE in coals is mainly the suspended terrigenous material. The specific enrichment of REE in the ash of low-ash coals is a result of the interaction between the dissolved REE and the products of disintegration and decay of organic substances, mainly the humic acids.     

陈家山矿煤中微量元素和稀土元素地球化学特征

通过对陈家山煤矿中下侏罗统延安组4#主采煤层中微量元素和稀土元素的测试分析,发现煤中富集亲花岗岩的钨钼族元素W、Mo、Bi、Sn、Ba、Sr和Li,说明该区煤系形成期间的陆源碎屑主要来自花岗岩和花岗片麻岩等中、酸性岩石。4#煤中ΣREE平均值为98.2×10-6,稀土元素分布模式十分相似,呈左高右低的宽缓“V”型曲线,Eu负异常明显,反映出稀土元素与陆源碎屑岩关系密切,成煤期间稀土元素来源一致,陆源物质的供应相对稳定。      

Rare earth elements and yttrium in lithotypes of Bulgarian coals

Rare earth element and yttrium abundances in vitrain, xylain, liptain, fusain and whole coal samples from Bulgarian coal deposits have been studied. Vitrain, xylain, and liptain are depleted, while fusain is enriched in REE and Y as compared to the whole coal samples from which they were selected. Chondrite-normalized patterns show relative enrichment of light (LREE) against heavy (HREE) rare earth elements, negative Eu anomaly, and positive Lu anomaly. The shale-normalized patterns of the lithotypes reveal an increase from LREE to HREE, while those of the whole coal samples and mineral interlayers are less fractionated. The petrographic composition of the coals is of secondary importance for the concentration of the REE and Y. The main factors are the source area and the input of dissolved REE and Y into the coal depositional sites.     

Flat rare earth element patterns as an indicator of cumulate processes in the Lesser Qinling carbonatites, China

The Lesser Qinling carbonatite dykes are mainly composed of calcites. They are characterized by unusually high heavy rare earth element concentrations (HREE; e.g. Yb > 30 ppm) and flat to weakly light rare earth element (LREE) enriched chondrite-normalized patterns (La/Yb_n = 1.0–5.5), which is in marked contrast with all other published carbonatite data. The trace element contents of calcite crystals were measured in situ by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Some crystals show reduced LREE from core to rim, whereas their HREE compositions are relatively constant. The total REE contents and chondrite-normalized REE patterns from the cores of carbonate crystals are similar to those of the whole rock. The carbon and oxygen isotopic compositions of calcites fall within the range of primary, mantle-derived carbonatites. The initial Sr isotopic compositions (0.70480–0.70557) of calcites are consistent with an EM1 source or mixing between HIMU and EM1 mantle sources. However these sources cannot produce carbonatite parental magmas with a flat or slightly LREE enrichment pattern by low degrees of partial melting. Analyses of carbonates from other carbonatites show that carbonates have nearly flat REE pattern if they crystallize from a LREE enriched carbonatite melt. This implies that when carbonates crystallize from a carbonatite melt the calcite/melt partition coefficients (D) for HREE are much greater than the D for the LREE. The nearly flat REE patterns of the Lesser Qinling carbonatites can be explained if they are carbonate cumulates that contain little trapped carbonatite melt. Strong enrichment of HREE in the carbonatites may require their derivation by small degrees of melting from a garnet-poor source.     

Mineralogical and elemental variation of coal from Alberta, Canada: an example from the No. 2 seam, Genesee Mine

Mineralogy and elemental contents were determined on 18 samples from a vertical profile of the No. 2 seam, Genesee mine, AB. The samples analyzed consist of coal, coaly shale, shaly coal, carbonaceous shale, shale, mudstone and siltstone. Proximate analysis was determined on all samples. Elemental analyses were determined by instrumental neutron activation analysis (INAA) for all elements except As, B, Cd, Hg, Mo, Pb, Se (Atomic Absorption) and B, Ba, Be, Co, Cr, Cu, Li, Mn, Nb, Sr and V (inductively coupled plasma-emission spectroscopy, ICP-ES). Samples were low temperature ashed (LTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF) were used to determine quantitative major mineralogy. Accessory mineralogy was determined with Scannining Electron microscope/energy dispersive X-ray analyzer (SEM/EDX) on four samples. In general, the coals in the Genesee mine are within the low end of the range for trace element contents given by Swaine [Swaine, D.J., 1990. Trace Elements in Coal. Butterworths, London, 278 pp.] for most coals. High contents of Cr (9–2620 ppm) and Ni (1–1440 ppm) can be related to an increased amount of a Cr–Ni–Fe oxide (chromite–magnetite?) likely derived from ultrabasic diatremes in the Golden-Columbia Icefields, BC area. The No. 2 seam of the Genesee mine can be divided into two geochemical cycles on the basis of mineralogy, trace element contents and rare earth element (REE) behavior. Cycle I consists of quartz, calcite and kaolinite, lower trace element contents, REE slightly enriched in high rare earth elements (HREE), and thick coal with few partings. Cycle II consists of quartz, calcite, kaolinite, illite, mixed layer and/or expandable lattice clays, feldspar, gypsum, calcium aluminum sulfate hydrate, clinoptilolite, calcite and diopside, higher trace element contents, REE slightly enriched in light rare earth elements (LREE) and thin coal with a greater frequency of partings. The differences between the two geochemical cycles can be accounted for by a decreasing stability of the peat-forming environment resulting from an increasing fluvial influence and volcanogenic input.     

Rare earth element patterns and crustal evolution—I. Australian post-Archean sedimentary rocks

A suite of Australian shales, greywackes and subgreywackes ranging in age from Proterozoic to Triassic were analyzed for the rare earth elements (REE) in order to detect any secular changes in rare earth distribution. These post-Archean sediments show remarkably similar relative rare earth patterns. They are characterized by negative Eu anomalies of almost constant magnitude (average Eu/Eu* = 0.67 ± 0.05) relative to chondrites and nearly constant ratios of light to heavy rare earths (average ∑LREE/∑HREE = 9.7 ± 1.8).

The REE abundances are generally higher in the younger sediments which may suggest that the absolute abundances of the rare earths in clastic sediments have gradually increased with time. Since no secular change in relative rare earth distribution was detected in the post-Archean sediments, a uniform process of crustal growth and evolution seems to have operated over the past 1500 million years at least.

Australites show rare earth distributions very similar to that of the average clastic sediment. This suggests that the tektite parent material originated in the upper crust.     

An improved description of the interactions between rare earth elements and humic acids by modeling: PHREEQC-Model VI coupling

The Humic Ion Binding Model VI (Model VI) - previously used to model the equilibrium binding of rare earth elements (REE) by humic acid (HA) - was modified to account for differences in the REE constant patterns of the HA carboxylic and phenolic groups, and introduced into PHREEQC to calculate the REE speciation on the HA binding sites. The modifications were shown to greatly improve the modeling. They allow for the first time to both satisfactorily and simultaneously model a large set of multi-REE experimental data with the same set of equations and parameters. The use of PHREEQC shows that the light rare earth elements (LREE) and heavy rare earth elements (HREE) do not bind to HA by the same functional groups. The LREE are preferentially bound to carboxylic groups, whereas the HREE are preferentially bound to carboxy-phenolic and phenolic groups. This binding differentiation might lead to a fractionation of REE-HA patterns when competition between REE and other metals occur during complexation. A survey of the available data shows that competition with Al³⁺ could lead to the development of HREE-depleted HA patterns. This new model should improve the hydrochemical modeling of the REE since PHREEQC takes into account chemical reactions such as mineral dissolution/precipitation equilibrium and redox reactions, but also models kinetically controlled reactions and one-dimensional transport.     

Rare earth element fractionation in magmatic Ca-rich garnets

Igneous garnets have the potential to strongly fractionate rare earth elements (REE). Yet informations on partition coefficients are very scant, and criteria for distinguishing between hydrothermal and magmatic garnets are ambiguous. To fill this gap, we present trace element and isotopic data for two types of Ca-rich garnets from phonolites (Mt. Somma-Vesuvius). Both Ca-garnet populations are different in their style and dynamics of fractionation: one population is progressively strongly depleted in HREE from core to rim, reflecting REE fractionation in the host phonolite via earlier-crystallized garnets. Such examples for extreme changes in HREE in garnets are only known for hydrothermal grandites by REE-bearing fluids. The second garnet population is homogeneous and formed in a closed system. Near-flat patterns between Sm and Lu confirm experimental data indicating lower D(Sm)/D(Lu) for Ca-rich garnets than for e.g. pyrope-rich garnets. It follows: D ^Grt/PhMelt for La = 0.5, Sm = 48 and Yb = 110.     

长江口东南泥质区百年来稀土元素的组成及控制因素

在210pb定年的基础上,分析了长江口外东南泥质区柱样沉积物稀土元素含量、特征参数分布特征及其与粒径、常量元素等的相关性,探讨了150 a以来稀土元素的来源、制约因素及对沉积环境的响应.结果表明,柱样稀土元素总量(ΣREE)变化范围不大,分布范围为158.38～197.87 μg/g,平均值为183.49μg/g,总体...     

Rare Earth Element Enrichment in Late Archean Manganese Deposits from the Iron Ore Group,East India

The major, trace and rare earth element (REE) composition of Late Archean manganese, ferromanganese and iron ores from the Iron Ore Group (IOG) in Orissa, east India, was examined. Manganese deposits, occurring above the iron formations of the IOG, display massive, rhythmically laminated or botryoidal textures. The ores are composed primarily of iron and manganese, and are low in other major and trace elements such as SiO₂, Al₂O₃, P₂O₅ and Zr. The total REE concentration is as high as 975 ppm in manganese ores, whereas concentrations as high as 345 ppm and 211 ppm are found in ferromanganese and iron ores, respectively. Heavy REE (HREE) enrichments, negative Ce anomalies and positive Eu anomalies were observed in post‐Archean average shale (PAAS)‐normalized REE patterns of the IOG manganese and ferromanganese ores. The stratiform or stratabound shapes of ore bodies within the shale horizon, and REE geochemistry, suggest that the manganese and ferromanganese ores of the IOG were formed by iron and/or manganese precipitation from a submarine, hydrothermal solution under oxic conditions that occurred as a result of mixing with oxic seawater. While HREE concentrations in the Late Archean manganese and ferromanganese ores in the IOG are slightly less than those of the Phanerozoic ferromanganese ores in Japan, HREE resources in the IOG manganese deposits appear to be two orders of magnitude higher because of the large size of the deposits. Although a reliable, economic concentration technique for HREE from manganese and ferromanganese ores has not yet been developed, those ores could be an important future source of HREE.     

鄂尔多斯盆地北缘延安组2号煤层稀土元素异常原因及其地质意义

鄂尔多斯盆地北缘延安组2号煤层稀土元素的异常原因一直存在着争议,以2号煤发育较完整的榆林大海则煤矿为例,运用电感耦合等离子质谱（ICP-MS）、扫描电子显微镜（SEM）等方法,分析煤及夹矸中稀土元素（REE）含量及其矿物学特征,并揭示稀土元素异常原因。结果显示:煤中总稀土元素（∑REE）含量为3.71~46.21 μg/g,轻稀土元素（LREE,La-Eu）比重稀土元素（HREE,Gd-Lu）更富集;稀土元素标准化配分模式图显示少数样品为Eu正异常;稀土元素含量较高的样品和拥有Eu正异常的样品主要分布在与夹矸距离较近的煤层中,表明煤中稀土元素分布受到了夹矸的影响;在夹矸中发现很多晶型较好的锆石、磷灰石、透长石及锐钛矿,这些矿物是在聚煤过程中接受火山物质的直接证据。综合认为,鄂尔多斯盆地延安组2号煤沉积期,盆地周缘存在一次火山活动,火山灰降落覆盖在泥炭沼泽之上,影响了聚煤作用,致使煤中稀土元素分布异常。研究结果解释了鄂尔多斯盆地北缘的煤中稀土元素异常原因,为研究区煤的加工利用方式提供参考。      

中条山地区早前寒武纪岩石 含铀矿化岩石稀土元素与铀的关系及其意义

本文研究了中条山地区基底涑水杂岩,含矿层中条群岩石和铀矿化岩石的稀土元素特征及其与铀元素的关系。发现稀土元素,尤其是重稀土元素对铀的区域富集及铀矿化作用有一定的指示意义。     

Geochemical behavior of rare earth elements in hydrothermally altered rocks of the Kuroko mining area,Japan

In this study we analyzed the chemical composition of hydrothermally altered dacite and basalt from the Kuroko mining area, northeastern Honshu, Japan, by REE (rare earth element). Features of rare earth element analyses include: (1) altered footwall dacite exhibits a negative Eu anomaly compared with fresh dacite, suggesting preferential removal of Eu²⁺ from the altered dacite via hydrothermal solutions, (2) altered hangingwall dacite and basalt and dacite and basalt adjacent to ore deposits exhibit positive Eu anomalies compared with fresh dacite and basalt, suggesting addition of Eu²⁺ from hydrothermal solutions, (3) LREE ratio (∑LREE/∑REE) from altered dacite of chlorite–sericite zone and K-feldspar zone show a negative relationship with δ¹⁸O, and La/Sm ratios show a positive correlation with the K₂O index. These trends indicate the addition of light rare earth elements such as La to the altered dacite from hydrothermal solution and/or leaching of heavy rare earth elements such as Sm and Yb, (4) Principal component analysis (PCA) indicates that light rare earth elements enrichment is related to the formation of sericite zone near the Kuroko deposits but not to the formations of chlorite and K-feldspar zones, and (5) The correlations among REE features (LREE ratio, MREE ratio, HREE ratio, Eu/Eu?), δ¹⁸O and K₂O index are not found for montmorillonite zone, mixed layer clay mineral zone and mordenite zone. Therefore, it is inferred that sericite, chlorite and K-feldspar alterations are related to the Kuroko and vein-type mineralization, but montmorillonite and mordenite alterations are not related to the mineralizations, and probably they formed at the post-mineralization stage.     

Behavior of rare earth elements in acid coal mine drainage in Shanxi Province, China

Rare earth element (REE) concentrations were determined in acid mine drainage (AMD), bedrock, pyrite, and coal samples from the Sitai coal mine and the Malan coal mine in Shanxi province, China. The AMD displayed high REE concentrations with typical convex shale-normalized patterns. The REE concentrations in the bedrock samples are one order of magnitude higher than those found in pyrite and coal samples. The high REE concentrations in AMD most likely come from the acidic solution leached out REE in bedrock. Results from laboratory and field experiments show that pH is the most important factor controlling the fractionation of REE; but Fe, Al, and Mn colloids and secondary minerals also affects their fractionation. As the pH increased from 4 to 6, the concentrations of total dissolved REE decreased from 520 to 0.875???g?L^?1. Fe and Al in AMD has less influence on the fractionation of dissolved REE than low concentrations of Mn. HREE were preferentially removed by secondary minerals and colloids, followed by MREE. Rare earth element??s speciation modeling indicates that sulfate complexes (LnSO₄ ⁺ and Ln(SO₄) ₂ ^? , 79?C91%) and free-metal species (Ln³⁺, 8.8?C21%) are the dominant REE species in the AMD, but the REE-sulfate complexation could not explain the MREE-enriched patterns.     

深海沉积物中的稀土矿产资源研究进展

近年发现,太平洋和印度洋的深海盆地中存在大量富含稀土的深海沉积物。主要类型为多金属软泥、沸石黏土和远洋黏土,其中的全稀土含量(∑REY,∑REE+Y)为400×10-6~2000×10-6,最高可达6600×10-6,重稀土含量(HREE)已达到或超过中国南方离子吸附型矿床的重稀土品位两倍以上,是潜在的新型稀土资源,具有重要的经济价值。目前不少学者对富稀土的深海沉积物进行了大量地球化学及部分矿物学的工作,认为多金属软泥中的稀土元素多赋存于与海底热液作用有关的铁锰氧化物和氢氧化物中,而沸石黏土和远洋黏土中稀土元素的富集则与磷酸盐的混入密切相关,其稀土元素主要存在于与磷灰石成分相当的生物鱼骨屑中。深海黏土的北美页岩标准化稀土配分模式与海水相似,表明其中的稀土元素主要来自于海水,REY富集成矿可能主要受控于磷灰石早期成岩阶段,期间稀土元素未发生分异。尽管近些年对深海沉积物中的稀土元素研究取得了不少成果,但是,对于沉积物中的稀土富集机制及影响因素等问题仍然需要更加深入的研究。作为稀土资源大国,为了争取我国在国际海底稀土资源竞争中的话语权,维护中国的稀土利益,中国应加紧开展相关的稀土资源勘查和潜力评价。     

柴北缘鱼卡地区中侏罗统石门沟组页岩段稀土元素地球化学特征与地质意义

对柴达木盆地北缘(简称柴北缘)鱼卡地区鱼油页1井(YYY-1)页岩段稀土元素地球化学分析,揭示了其对古环境、古物源和古气候的响应,并探讨了对油页岩成矿的影响。分析结果表明:石门沟组页岩段稀土元素总量(ΣREE)为(139.16~342.59)×10~(-6),平均值为236.66×10~(-6),高于北美页岩(NASC)和后太古宙页岩(PASS)。ΣLREE/ΣHREE和(La/Yb)_N等地球化学参数表明,轻重稀土元素分异明显;分布模式为轻稀土元素富集、重稀土元素相对亏损。地球化学参数以及La/Yb-ΣREE图解表明,研究区物源主要为上地壳沉积岩和火山岩的混合来源。元素Eu具有明显的负异常,指示沉积水体为缺氧的还原环境,为油页岩中有机质的富集提供良好的保存条件。根据高含量的ΣREE值以及δEu异常值,结合前人对该地区的孢粉研究成果,石门沟组页岩段形成于暖湿的气候条件,为油页岩的形成提供良好的物质来源和保存条件。     

REE characteristics of the coal in the Erlian Basin,Inner Mongolia,China, and its economic value

The rare earth elements (REE) content of the coal in the Erlian Basin was determined by inductively coupled plasma mass spectrometry (ICP-MS), and it turns out that the REE content from different geological age shows a significant difference: The REE content of the coal in the Jurassic Alatanheli Group is from 152.05×10⁻⁶ to 1416.21×10⁻⁶, with an average value of 397.31×10⁻⁶, and the relative concentration factor shows enriched; the REE content of the coal in Early Cretaceous Baiyanhua Group is from 20.65×10⁻⁶ to 102.53×10⁻⁶, the mean value is 49.06×10⁻⁶, and the relative concentration factor shows normally. The REE distribution patterns samples in Jurassic and Cretaceous shows the difference: The REE pattern in Jurassic coal mainly manifests as H-type distribution, with the Y, Lu positive anomaly, it is speculated that the fluid carried REE ions into the coal-bearing basin, and the heavy REE gather in the coal due to the different chemical properties of each REE. The REE occurrence mode is presumed to be mainly organic. Flat type is the REE main distribution pattern in Cretaceous coal. The REE patterns in clastic rocks of the roof, parting and floor of coal seam are similar to the REE patterns in the coal and the most possible reason is that the REE main source is from the clastic rock. It showed that the coal of the Early Jurassic, especially of Amugulen coalfield has resource value.     

Rare earth element geochemistry and petrogenesis of miles (IIE) silicate inclusions

An ion probe study of rare earth element (REE) geochemistry of silicate inclusions in the Miles IIE iron meteorite was carried out. Individual mineral phases among inclusions have distinct REE patterns and abundances. Most silicate grains have homogeneous REE abundances but show considerable intergrain variations between inclusions. A few pyroxene grains display normal igneous REE zoning. Phosphates (whitlockite and apatite) are highly enriched in REEs (50 to 2000 × CI) with a relatively light rare earth element (LREE)-enriched REE pattern. They usually occurred near the interfaces between inclusions and Fe host. In Miles, albitic glasses exhibit two distinctive REE patterns: a highly fractionated LREE-enriched (CI normalized La/Sm ∼15) pattern with a large positive Eu anomaly and a relatively heavy rare earth element (HREE)-enriched pattern (CI-normalized Lu/Gd ∼4) with a positive Eu anomaly and a negative Yb anomaly. The glass is generally depleted in REEs relative to CI chondrites.The bulk REE abundances for each inclusion, calculated from modal abundances, vary widely, from relatively depleted in REEs (0.1 to 3 × CI) with a fractionated HREE-enriched pattern to highly enriched in REEs (10 to 100 × CI) with a relatively LREE-enriched pattern. The estimated whole rock REE abundances for Miles are at ∼ 10 × CI with a relatively LREE-enriched pattern. This implies that Miles silicates could represent the product of a low degree (∼10%) partial melting of a chondritic source. Phenocrysts of pyroxene in pyroxene-glassy inclusions were not in equilibrium with coexisting albitic glass and they could have crystallized from a parental melt with REEs of ∼ 10 × CI. Albitic glass appears to have formed by remelting of preexisting feldspar + pyroxene + tridymite assemblage. Yb anomaly played an important role in differentiation processes of Miles silicate inclusions; however, its origin remains unsolved.The REE data from this study suggest that Miles, like Colomera and Weekeroo Station, formed when a molten Fe ball collided on a differentiated silicate regolith near the surface of an asteroid. Silicate fragments were mixed with molten Fe by the impact. Heat from molten Fe caused localized melting of feldspar + pyroxene + tridymite assemblage. The inclusions remained isolated from one another during subsequent rapid cooling.     

中、下扬子地区下寒武统黑色页岩微量元素富集特征

中国南方扬子地区下寒武统黑色页岩分布广泛,主要由黑色页岩、黑色白云质页岩,黑色粉砂质页岩和黑色硅质页岩等组成;并伴生有较厚的磷块岩矿床、钒矿床和镍、钼多元素硫化物矿床。对黑色页岩岩石学特征、元素地球化学特征进行系统研究,并详细分析微量元素的富集成因,结果表明：黑色页岩主要形成于静水还原的浅海-半深海缓坡环境,层状元素富集带为沉积成因,海底热流体提供了丰富物质来源。总体上,Co、Be、Mn、Ga等元素含量较低;Cu、V、Ni、Mo等元素的含量较高,多数超过北美页岩平均值;以Ni、Mo为主的多元素富集层通常位于磷块岩之上,以黑色页岩、黑色白云质页岩中的硫化物和硫酸盐矿物为主要载体,其中有机碳（TOC）含量可达12.2%以上,远高于其他元素富集层,随着页岩内硅质成分增加,Ni、Mo、Fe、Co等元素含量明显降低;以V为主的多元素主要赋存于黑色硅质页岩中的水云母,与页岩内硅质成分具有较好的正相关关系;黑色页岩中稀土元素含量为(76.22~290.67)×10-6,轻重稀土比值LREE/HREE介于1.21~4.22,说明轻稀土更为富集,Sr/Ba值为0.04~0.34,δEu正异常,且北美页岩标准化配分曲线呈现平缓左倾,为沉积过程中存在海底热水流体提供了进一步证据。     

巴格毛德油页岩中稀土元素特征研究及其地质意义

油页岩中的稀土元素（REE）研究不仅可以用于解决岩石地质成因,提供物质来源信息,而且可以对REE含量进行资源评价,有利于油页岩的综合开发利用,具有重要的理论和现实意义。本研究测试并分析了银额盆地巴格毛德凹陷中生界白垩系下统巴音戈壁组（K1b）巴格毛德油页岩REE地球化学特征,分析结果表明,油页岩中的REE总量（∑REE）为94．8×10^-6～178×10^-6,平均值为126×10^-6,低于其围岩的∑REE;轻、重稀土元素含量比值（∑LREE／∑HREE）为2．60～3．45,平均值为3．10。（La／Yb）w为0．57～1．02,平均值为0．89,表明油页岩中LREE、HREE分异不明显,LREE相对HREE富集,属于LREE低度富集型。Eu表现为明显负异常,Ce表现为微弱的正异常,表明了油页岩形成于还原的古湖泊环境。油页岩样品∑REE与其微量元素的聚类分析结果表明,油页岩中的REE主要来自陆源碎屑沉积。油页岩样品δCe与δEu、δCe与∑REE均无明显的相关关系,表明成岩作用对REE的影响十分有限,研究区油页岩的成岩阶段处于未成熟阶段。