华南地区晚二叠和晚三叠世煤中稀土元素特征研究

在华南地区贵州六盘水、江西乐平、露庆和湖北黄石矿区晚二叠和晚三叠世煤层的稀土元素ICP—MS分析数据的基础上，系统研究了研究区煤中稀土元素的含萤分布特征、赋存特征、配分模式以及地质控制因素。含量分布表明晚二叠世稀土元素含量总体高于晚三叠世；煤中稀土元素与灰分成正相关关系，部分煤样品由于有富稀土元素的重矿物组合的存在而出现稀土元素的异常高值；同一矿区、同一时代煤中稀土元素的配分模式具有一定的相似性，而不同地区同一时代和同一地区不同时代煤中稀土元素的配分模式具有较大差异；煤的沉积环境，煤中无机矿物组成以及海水的影响是控制煤中稀土元素含量和配分模式的主要地质因素。     

东风山前寒武纪含铁建造金矿床中的稀土元素

东风山含铁建造金矿床中稀土元素含量普遍较低。东风山群是含矿层,其不同层位岩石和矿物的稀土含量有所差别。大理岩和含铁层中铁闪石的稀土含量最低,甚至低于稀土地壳丰度;上部角岩、下部角岩和石榴子石中稀土含量近似其他壳丰度;而板岩和花岗岩中稀土含量远高于其他壳丰度。稀土元素分布的特点反映了东风山金矿床形成于一个半封闭和较还原的海盆地,金矿化是在弱碱性条件下产生。黄铁矿中出现独居石类矿物,这可能与陆壳重熔改造形成花岗岩时产生的局部富轻稀土热液沿黄铁矿裂隙渗入有关。     

北大巴基性岩墙群地球化学特征、LA-ICP-MS锆石U-Pb定年及其大地构造意义

北大巴地区广泛分布了呈北西-南东向产出的基性岩墙群,主要侵位于下古生界。对该套岩系的地球化学分析表明,w（K2O＋Na2O）、w（TiO2）高,总稀土元素质量分数高并呈轻稀土元素富集型,大离子亲石元素明显富集,Ta、Nb的质量分数远高于洋中脊玄武岩,具大陆裂谷玄武岩的地球化学特征。采用LA-ICP-MS法对北大巴基性岩墙中的岩浆锆石进行了U—Pb同位素定年,获得岩体结晶年龄为（431．0＋3．2）Ma。地球化学及年代学数据表明,北大巴基性岩墙群具有大陆裂谷玄武岩的地球化学特征,表明北大巴早古生代伸展构造受到扬子板块北缘的幔源裂谷作用制约。在裂谷演化过程中,上地幔物质上涌造成岩石圈板块拉伸减薄,使北大巴地区中上地壳发生强烈构造伸展并形成大面积呈线状分布的基性岩墙群,并且该处（431．0±3．2）Ma的年龄值代表了在早志留世北大巴裂谷盆地的伸展裂陷幅度达到最大。     

Rare-Earth Elements in the Atmospheric Precipitation of the City of Blagoveshchensk

The mineral composition, distribution and fractionation of rare-earth elements in dissolved and suspended forms (solid residue) of atmospheric precipitation were studied by analyzing the snow sampled over urbanized territory by the example of the city of Blagoveschensk. Electron-microscopic studies revealed the own minerals of rare-earth elements in dust aerosols. It is shown that the main sources of the atmospheric pollution by rare-earth elements were emissions of TPP (heat and power plants) and boiler houses. Contrasting geochemical anomalies of rare-earth elements were found in the snow cover of the city. The REE concentrations in the solid phase of snow are few orders of magnitude higher than those of the liquid phase. The snow solid phase provides insight into the REE behavior, because it directly reflects the impact of different anthropogenic sources. The characteristic feature of the REE distribution in the solid residue of snow is their LREE enrichment relative to MREE and HREE. The average HREE content is 10% of total REE. In the snow water–solid phase system, most samples show weak fractionation between LREE and HREE owing to the low total mineralization of the snow liquid phase and the small content of organic matter.     

内蒙古乌兰浩特地区正长花岗岩LA-ICP-MS锆石U-Pb年龄及其地质意义

为探讨乌兰浩特地区正长花岗岩形成时代及其构造环境,对其进行锆石U-Pb年龄和岩石地球化学研究。结果表明: LA-ICP-MS锆石U-Pb年龄为(219.7±1.2) Ma,代表了其成岩年龄; 岩石高硅、高碱,贫铝、钙、镁、铁; 岩石稀土含量偏高,轻重稀土分馏不明显,Eu负异常明显; 在微量元素上,富集大离子亲石元素Rb、K,贫Sr、Eu、Ba,富高场强元素U、Th、Hf、HREE,贫Ti; 10 000×Ga/Al值(3.53~5.09)均大于A型花岗岩的下限值(2.6),明显高于I型和S型花岗岩的平均值(分别为2.10和2.28)。因此,晚三叠世正长花岗岩为A型花岗岩,推断其形成于古亚洲洋闭合后的造山后岩石圈伸展构造环境。     

蒙古-鄂霍次克洋的远程作用:来自内蒙古东南部羊盘沟地区流纹斑岩成因的证据

为了解蒙古—鄂霍次克构造体系的远程作用及其在中国东北以南的影响范围,在内蒙古多伦火山盆地羊盘沟地区开展了流纹斑岩锆石U-Pb同位素年代学、岩石地球化学及区域对比研究.结果显示,其形成时代为144.2±0.6 Ma,属于早白垩世早期.主量元素SiO₂含量为73.25%~76.72%,K₂O含量为4.64%~7.87%,K₂O/Na₂O值在1.15~3.82之间,A/CNK值为0.79~0.99;副矿物为磁铁矿、锆石和磷灰石等,属准铝质高钾钙碱性—钾玄岩系列A₂型流纹岩类;稀土元素总量高(320.76×10-6~415.70×10-6),富集轻稀土元素、大离子亲石元素K和Rb、高场强元素Zr和Hf以及元素U、Th等,亏损重稀土元素、大离子亲石元素Ba和Sr、高场强元素Nb和Ta以及元素P、Ti等,显著Eu负异常(δEu=0.08~0.15).表明流纹斑岩形成于后碰撞构造环境,是早白垩世蒙古—鄂霍次克洋闭合后某个伸展事件下的产物,因此,蒙古—鄂霍次克构造体系在中国的影响范围向东南至少延伸至蒙东南—冀北一带,且对应的蒙古—鄂霍次克洋东段的闭合完成时间应早于144.2 Ma.      

桂北摩天岭含铀花岗岩体岩石地球化学特征

本文按摩天岭含铀花岗岩体的花岗岩、弱蚀变花岗岩、钾交代花岗岩和硅质交代花岗岩4种岩石类型,探讨了岩石中的常量元素、大离子亲石元素(LILE)、高场强元素(HFSE)和稀土元素(REE)含量特征及相互间的关系。其中含铀钾交代花岗岩表现为强钾长石化、强绿泥石化和弱赤铁矿化,U含量与次生黑云母关系密切;含铀硅质交代花岗岩的U含量与微晶石英伴生的铁质有关。通过剖析不同类型岩石的地球化学特征,指出成矿流体的元素主要来自花岗岩,产铀岩石具明显的LLH特征;伴随铀矿化的增强,K/Ba、Rb/Sr值降低,而Ba/Rb值增高;含铀钾交代花岗岩和硅质交代花岗岩的HFSE和REE含量呈共轭消长和重稀土(HREE)相对富集的特征。提出伴随断裂开启多期成矿流体的叠加更有利于铀的富集,LLH特征,以及K/Ba、Rb/Sr值降低与Ba/Rb值增高可作为含铀花岗岩体的地球化学判别依据。     

浅谈湖泊沉积环境演变中元素地球化学的应用及原理

湖泊沉积物中某些元素的含量、比值及分布特征在区域气候与环境变化方面的应用研究发展迅速.介绍了常量元素的含量及其比值分析,有机质中特征元素含量及比值分析,同位素分布特征,稀土元素模式分析几个方法.利用常量元素和有机质特征元素的含量及比值的升高或降低来指示沉积时期湖泊流域温度、降水量等气候变化并建立湖泊演变的气候干湿波动曲线,也可以获得沉积时期元素迁移变化的过程;利用同位素分布特征和稀土元素模式分析来测定沉积速率和建立演化年序,也可以判断湖泊演化过程和水源补给条件等.     

湘南花岗岩体稀有稀土元素成矿地质特征的初步认识

含稀有稀土元素花岗岩型矿体,为我国稀有稀土元素的主要工业类型,湘南是我国稀有稀土元素重要成矿区之一。区内岩体众多。本文概述了湘南花岗岩的特征,结合稀有稀土元素矿化特征讨论了各不同花岩类与稀有稀土元素的关系,对其成矿地质特征进行了初步的总结和探讨。     

三江地区澜沧江带南段南林山基性岩体锆石U-Pb年龄及岩石地球化学特征

南林山基性岩体位于西南三江地区,岩体主要由辉长岩和闪长岩组成。通过ID-TIMS锆石U-Pb年代学方法对南林山岩体中闪长岩进行精确定年,获得其结晶年龄为（298.44±0.33）Ma,表明南林山基性岩体的形成时代为早二叠世。全岩主量、微量元素与稀土元素等研究表明,辉长岩和闪长岩总体上均呈现轻稀土元素（LREEs）相对于...     

冕宁稀土矿床稀土元素的赋存状态及其配分特征

冕宁稀土矿是我国西南地区的大型轻稀土矿床。它不仅含有丰富的轻稀土,而且铕、钇等中重稀土较国内外同类型矿床高。该矿的特点是工业稀土矿物组成简单,矿石易选、易冶。矿石中90％左右的REO呈稀土矿物产出,其中氟碳铈矿占稀土矿物总量的80％—97％。矿石和主要稀土矿物的REF配分均属Ce>La>Nd富LREE的强选择配分型。矿石中轻稀土配分值高达97.48％—98.81％。矿石中Eu、Y配分值较高,而氟碳铈矿反而比矿石低。矿石中的黑色风化土状物富含次生稀土,其Eu、Y配分值比矿石、氟碳铈矿都高。     

The Behaviour of Rare—Earth Elements（REE） During Weathering of Granites in Southern Guangxi,China

The behaviour of the rare-earth elements(REE)during the weathering of granites was studied in southern Guangxi,China.Based on the study of the weathering profiles,the soil,weathered and sub-weatereb zones are identified with different REE geochemical behaviours throug the weathering profiles of granite.The Ce anomalies of the weathering profiles cover a large range of values with most falling between 1.02 and 1.43in the soil zone and 0.16and 0.40in the weathered and sub-weathered zones.Light rare-earth elements(LREE) and heavy rare-earth elements(HREE)are enriched to varying degree in the weathering profiles as compared to host granites.In the soil zone,more HREEs are leached than LREEs,and HREEs are more enriched than LREE in the weathered and sub-weathered zones.It is considered that infiltration and adsorption on clays are two processes controlling the enrichment and formation of REE deposits in the weathering profiles of granite.     

Isotopic-geochemical signs of the transformation of coal and bitumen during the ore mineralization of different types: Communication 2. Geochemical regularities in the distribution of rare earth and trace elements supplemented with the model of structural transformation of coal and bitumen during ore genesis

Regularities in the distribution of rare-earth and trace elements in organic matter depending on geological settings and geochemical processes are considered. The model of transformation of organic matter and redistribution of ore elements during oil generation and ore formation is discussed.     

Determination of Thirteen Rare-Earth Elements by High-Performance Liquid Chromatography in Thirty and of K, Rb, Cs, Sr and Ba by Isotope Dilution Mass Spectrometry in Eighteen International Geochemical Reference Samples

This study reports the results of thirteen rare-earth elements in thirty geochemical reference samples. Three alkali (K, Rb, Cs) and two alkaline earth (Sr, Ba) elements were also determined in eighteen reference samples. The analytical procedure involved is based on spiked samples and later measurement of the rare-earth elements by high-performance liquid chromatography and the alkalies and alkaline earths by thermo-quartz mass spectrometric isotope dilution (THQ-MSID). Whenever possible, the results are compared with literature values.     

Rare—Earth Elements and Genesis of Lamprophyres in the Laowangzhai Gold Orefield,Yunnan Province

The Laowangzhai super-large gold orefield,which is situated in northern Mt.Ailao tectonic zone,Yunnan Province,is a typical gold orefield where lamprophyres are temporally and spatially related to gold mineralization.Major element data show that lamprophyres in the orefield are of alkalic series and can be divided into potassic and K-rich calc-alkaline lamprophyres.The rocks are enriched in rare-earth elements as compared with the primary mantle and mid-ocean ridge basalts(MORB).Modelled calculations by the least squares method of Petrological Mixing show that the mantle-source for the lamprophyres in enriched in rarc earth elemeots.The geotectonic development of western Yunnan,Sr and Nd isotopic compositions,incompatible element patterns and linear programing calculations indicate that the fluids were derived from dehydration of submaine sediments which are enriched in ALK,LREE and incompatible elements and then were carried to mantle wedges as a result of plate subduction.That is the main factor leading to the formation of a metasonatic fertile mantle in the area studied.     

华南地区晚二叠世煤的稀土元素特征

在华南地区贵州六盘水、江西乐平和湖北黄石矿区以及重庆钟梁山和磨心坡煤矿晚二叠世煤的稀土元素电感耦合等离子质谱分析数据的基础上,系统研究了华南地区煤的稀土元素的质量分数分布特征、赋存特征、配分模式及其地质控制因素.煤的稀土元素质量分数与灰分质量分数呈正相关关系,部分煤样品由于有富稀土元素的重矿物组合的存在而出现稀土元素的异常高值.同一矿区晚二叠世煤的稀土元素配分模式具有一定的相似性,而不同地区晚二叠世煤的稀土元素配分模式则差异较大.煤的沉积环境、煤中无机矿物的组成以及海水的影响是控制煤的稀土元素质量分数及其配分模式的主要地质因素.     

Rare-Earth Elements Contents of Four New Canadian Standard Rocks of Iron-Formation

The rare-earth elements (REE) content of the FER-1, -2, -3, -4 canadian reference samples has been determined by neutron activation and high-resolution X-ray or γ-ray spectrometry. As these rocks are included in a new project of standardisation, the present results have not been compared with other data.     

华北板块北缘东段早前寒武纪稀土元素演化特征

通过对区内早太古宙深变质地体、晚太古宙花岗岩-绿岩地体,晚太古-早元古宙优地槽和火山岛弧各类变质岩稀土元素的研究,三个时期的稀土元素具大致相似的演化特征,不同时期相同的岩石类型的稀土配分型式也大致相似,反映了它们有着相同源岩。但是,它们又在稀土丰度、Eu异常和轻、重稀土分离程度方面表现出某些差异,表明本区在早前寒武纪的不同时期、不同构造环境中地壳成分的不均一性。不同岩石类型稀土配分的多样性,说明岩浆源不同,至少有超镁铁质、镁铁质和安山质或英云闪长岩-奥长花岗岩三种岩浆源。     

柴达木盆地东南缘晚三叠世火山岩地球化学特征及构造环境分析

柴达木盆地东南缘晚三叠世鄂拉山组火山岩主要为一套中一酸性火山岩组合,以流纹岩、英安岩为主,其次为安山岩.主量元素、稀土元素及微量元素的分析结果表明:其样品的里特曼指数δ小于4,属钙碱性岩石系列;SiO2的平均值为71.95％,大部分样品具低铝特征,且碱质含量较高,属于亚碱性火山岩.轻重稀土比值较大且负铕异常明显,具典型...     

Geochemistry of Rare and Rare-Earth Elements in Manganiferous Sediments of the Polar Urals and Pai-Khoi

Lithology and Mineral Resources - Data on the concentration of rare and rare-earth elements in the Devonian manganese-rich metasediments of the Polar Urals and Pai-Khoi Ridge are presented. It is...