长江中下游马头斑岩型钼铜矿床常量元素、稀土元素特征及迁移规律研究

安徽马头钼铜矿是长江中下游成矿带中斑岩型矿床的典型代表,矿床在空间上划分出了3个不同的蚀变分带,即钾长石化带、石英-绢云母化带和青磐岩化带.本文对该矿床不同蚀变带内的常量元素迁移规律和稀土元素特征进行了探讨:①常量元素的迁移规律明显,从钾长石化带和石英-绢云母化带到青磐岩化带,均为带入的主要成分有K2O、CaO、Fe2O3、SiO2、H2O+,说明引起蚀变的流体中富含K2O、CaO等;而Na2O、FeO、MnO等成分的明显带出,说明矿化蚀变作用导致Na2O、FeO等成分向矿体迁移方向流失,其中Na2O的贫化最明显,与成矿元素Mo、Cu呈显著的负相关.②马头钼铜矿床花岗闪长斑岩的稀土配分模式图表现为左高右低的较平滑曲线,轻稀土富集,重稀土亏损.稀土元素的质量迁移计算结果同样证明了稀土元素在矿化蚀变过程中发生了分馏,且从钾长石化带到青磐岩化带,稀土元素带出量呈递增趋势.③该矿床样品的稀土元素配分特征表明,较新鲜花岗闪长斑岩与蚀变围岩的曲线基本相同,表明成矿物质主要来自花岗闪长岩熔体,并且可能有海水的混入.由δEu、δCe值及Fe2O3与FeO带出带入的关系可知,斑岩流体晚期氧逸度逐渐升高,表明成矿环境可能由相对还原过渡到氧化环境.④除Al2O3、TiO2保持惰性外,常量元素、稀土元素在矿化蚀变过程中都发生不同程度的带入带出,富集贫化特征和迁移规律不完全相同.     

新疆青河县库布苏破碎蚀变岩型金矿元素迁移特征与规律研究

本文以新疆库布苏金矿北矿带为研究对象,讨论了库布苏金矿床北矿带元素活动特征,成矿及伴生元素、主量元素、微量元素、稀土元素的质量迁移规律;根据稀土元素的质量迁移、地球化学特征,初步探讨了成矿流体的环境条件和来源问题;并依据元素迁移地球化学图研究了库布苏北矿带105勘探线剖面的元素质量迁移程度和范围。研究结果表明,赋矿闪长玢岩脉及围岩的元素发生明显的带入带出作用,元素迁移活动规律明显,成矿阶段发生明显带入有Au、As、Bi、Ag、Sb、K2O、Si O2,说明引起闪长玢岩脉和接触带围岩蚀变的流体中富含Au、As、K2O、Si O2等,导致这些带入元素向矿体迁移富集;发生明显带出的有Ba、Sr、Cu、Mg O、Na2O、Fe2O3、Ca O,说明Ba、Sr、Mg O、Na2O等受热液蚀变作用随流体迁出。矿区岩脉的稀土元素质量变化显著,发生明显的带入带出,岩脉交代蚀变前后的轻重稀土分馏均明显,蚀变后的岩脉轻重稀土分馏程度有减小趋势。赋矿闪长玢岩脉稀土元素配分曲线右倾,轻稀土富集,轻重稀土分馏明显,Eu强烈负异常,Ce弱负异常,说明库布苏金矿成矿流体条件应为较高温度和还原环境。从围岩与脉岩中元素的迁移程度和迁移范围可见,带入的成矿指示元素有As、W、Sb、Bi,带出的成矿指示元素有Mg、Na。     

安徽铜陵桂花冲斑岩铜矿围岩蚀变与矿化作用

桂花冲铜矿为安徽铜陵地区新发现的斑岩型铜矿,斑岩体为准铝质高钾钙碱性的花岗闪长斑岩。围岩蚀变与矿化作用是斑岩型矿床成矿过程研究的一项重要内容,对蚀变带岩石开展元素地球化学成分的迁移研究,是分析热液交代蚀变过程的基础。桂花冲铜矿区内围岩蚀变作用比较强烈,蚀变类型主要有钾化、绢云母化、硅化、绿泥石化和碳酸盐化等。蚀变分带比较明显,由内向外依次为钾化带、绢英岩化带和青磐岩化带,矿体主要产于绢英岩化带内。矿化蚀变自早至晚划分为钾长石、石英-绢云母、石英多金属硫化物和碳酸盐4个阶段。蚀变带物质组分迁移结果表明,在蚀变过程中,岩石的主量元素除TiO₂、MnO、MgO外,其他元素迁移量发生了明显改变;微量元素除Sr和Cu外,迁移量变化较小,稀土元素在矿化强的部位亏损,在矿化弱的地带富集。岩体及蚀变带岩石稀土元素球粒陨石标准化配分模式一致,说明岩体与蚀变岩石经历了相同来源流体的交代蚀变,是岩浆流体连续作用的结果。     

早子沟金矿成矿过程中的元素迁移规律及金富集机制探讨

早子沟金矿位于秦岭造山带西段夏河—合作断裂带上,成矿作用与断裂构造关系密切,蚀变带受断裂构造控制,本文通过对矿区蚀变带内常量元素的迁移规律研究,通过计算得到矿区明显带出的组分为SiO2、Al2O3、K2O、MnO,而Fe2O3、Na2O则明显带入,探讨了元素迁移的性状及其与蚀变类型的关系,并对矿床金富集机制做了简要分析。     

福建紫金山金铜矿床过渡带地球化学特征及地质意义

紫金山矿田是东南沿海武夷成矿带中重要的多金属矿集区,是与中生代构造-岩浆活动有成因联系的多金属矿产地。根据对矿田露采区近矿蚀变围岩和金铜矿石的主量元素、微量元素和稀土元素进行了详细的分析和总结。主量元素特征显示,SiO_2、Fe_2O_3在矿石和蚀变围岩中明显富集,Al_2O_3、MnO、MgO、CaO、Na_2O、K_2O在矿石和蚀变围岩中的含量明显低于复式岩体,矿石和蚀变围岩中的富集组分(SiO_2、Fe_2O_3)不可能来自复式岩体,而应该是来自成矿热液,显示了多期次的蚀变作用与矿化密切相关;稀土元素特征显示,蚀变英安玢岩和矿石稀土元素地球化学特征相似,明显富集轻稀土元素,轻重稀土元素内部分异明显且轻稀土元素内部分异现象更严重,Eu弱负异常,二者的稀土元素配分模式图也十分相似,表明成矿流体来源更可能是与英安玢岩同源的岩浆热液;综合研究表明,成矿作用与幔源岩浆的参与有关,成矿物质可能主要来自幔源岩体,紫金山复式岩体也可能提供了部分成矿物质,说明深部可能存在斑岩型铜钼矿床。     

河北省木吉村铜(钼)矿床蚀变分带过程中元素迁移定量分析

为了研究木吉村斑岩型铜(钼)矿床蚀变过程中元素的迁移规律,拟推流体演化规律,笔者通过对赋矿闪长玢岩体的强硅化带、钾长石化带、石英绢云母化带、青磐岩化带中分别取样测试分析,利用Grant方程定量探讨了各蚀变带围岩中主量元素、稀土元素和微量元素的带入、带出特征,结果表明:岩浆初始热液流体富K而贫Na。相对原岩(蚀变弱的青磐岩化带),在各蚀变带中Fe_2O_3、MgO、P_2O_5和TiO_2从深部强硅化带到浅部石英绢云母化带总体上由带出变为带入,SiO_2、MnO则与上述大体相反,FeO在各蚀变带主体为带出元素。各稀土元素从深部向浅部石英绢云母化带带入特征明显,同时各蚀变带在稀土元素球粒陨石标准化曲线上表现出斜率一致的右倾型特征,说明轻重稀土分馏较明显,轻稀土富集,重稀土亏损。Cu和Mo在石英绢云母化带中富集尤为明显,其次在钾长石化带也明显富集,即海拔400~500 m为主要的Cu、Mo富集区。     

粤北302铀矿床围岩蚀变的地球化学特征和成因研究

以粤北302铀矿床ZK23-2钻孔为研究对象,通过显微镜下薄片鉴定、岩石地球化学和流体包裹体分析等对该矿床的围岩蚀变进行研究。结果表明,302矿床蚀变种类繁多,蚀变类型主要有:碱性长石化、硅化、绢云母化、红化、绿泥石化、绿(褐)帘石化、碳酸盐化、高岭石化等。矿床表现出明显的垂直分带和水平分带特征。从上至下,将ZK23-2划分为4个蚀变带:红化、绢云母化带→硅化、红化、强绢云母化带(铀富集带)→绿泥石化、绢云母化带→弱蚀变或正常花岗岩带。岩石的主量元素、微量元素和稀土元素均规律变化,微量元素分布模式和稀土元素配分模式均与赋矿围岩长江岩体的趋势一致,说明蚀变作用对它们的影响小,致使蚀变岩石基本保持原岩的地球化学特征。各蚀变带包裹体的均一温度均低于220℃,属于中低温热液,惰性气体N2在各蚀变带包裹体中普遍存在,强蚀变带的包裹体气相成分中均含CO2,表明在铀矿的形成过程中,铀的溶解、迁移以及富集成矿作用与CO2气体密切相关并发生在N2环境中。此外,成矿期脉石矿物包裹体的均一温度和压力为正相关的平滑曲线,表明围岩蚀变的分带特征主要是由成矿热液流体的混合作用引起的。     

热液型金矿床围岩蚀变过程中元素迁移规律--以张家口地区东坪、后沟、水晶屯金矿为例

张家口地区东坪、后沟、水晶屯金矿围岩蚀变发育 ,主要的蚀变类型有钾长石化、硅化、黄铁矿化、绿泥石化等。通过蚀变岩常量元素、微量元素的定量计算发现 ,三个金矿床围岩蚀变过程中元素迁移、富集有明显的规律 ,即常量元素 (SiO2 、K2 O、FeO) ,亲硫元素 (成矿元素 :Au、Ag、As、Sb、Bi、Pb、Zn)明显富集 ,其它亲铜亲铁元素 (Cr、Co、Ni、Cu)略有富集。蚀变热液是一种来自深部的携带亲硫元素富硅的碱性流体     

胶东招平断裂带围岩蚀变地球化学特征

招平断裂带是胶东地区重要的金成矿带, 众多蚀变型、石英脉型金矿床产出于该带及下盘次级断裂中。以招平断裂带破头青断裂为研究对象, 进行剖面测量和取样测试分析, 探讨围岩蚀变地球化学特征。研究结果显示, 招平断裂带破头青断裂蚀变分带明显, 不同蚀变强度的蚀变岩中常量元素迁移规律明显, REE配分曲线表现为HREE富集, Eu、Ce均有较明显的负异常, 从弱蚀变至强蚀变过程中, ΣREE、LREE和HREE均有明显降低, 且相应特征值表现出规律的变化, Au-Ag-Bi-Co-Cu-Mo-Ni-Pb-Zn是金成矿密切相关的指示元素组合。      

居隆庵铀矿床蚀变分带及其地球化学特征

以产于碎斑流纹岩中的铀矿化蚀变为例,对居隆庵铀矿床蚀变分带及其地球化学特征进行了系统研究,将该区蚀变分成5个带。地球化学研究表明,围岩蚀变过程中元素迁移、富集有明显的规律;常量元素（Ca、Mg、K、S）、微量元素（Cu、Pb、Zn、As、Sb、Th、Mo、W、F）和稀土元素（REE）有明显富集;亲硫元素是铀成矿作用的指示元素;成矿过程至少经历了两次热液活动;成矿流体具有还原性和深源性。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an     

PROSPECTING EXPLORATION

正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of