西秦岭温泉混浆花岗岩的微量与稀土元素地球化学特征

西秦岭温泉岩体是壳、幔岩浆混浆的产物。寄主岩石高Mo、Sn、Bi、W等高温热液成矿元素及Co、Ni、Cr等亲铁元素。而基性端元的暗色微细粒镁铁质包体及基性岩墙则异常富集轻稀土和Ba、Rb、Sr、Zr、Th、Hf、Nb等大离子亲石元素，贫Co、Ni、Cr等亲铁元素，微量元素的反常分布，指示了两个端元元素演化的显著依从性和交换性。LREE／HREE值在寄主岩石中为10～15，受岩浆混合作用影响在基性端元为9．98～13．5，异常富轻稀土。δEu值及(La／Sm)N、(Gd／Yb)N、(La／Yb)N等比值，显示该岩体为混浆花岗岩。岩浆混合作用强烈的混浆暗色花岗岩具有显著的壳慢过渡性质。     

西秦岭温泉岩浆混合花岗岩的地球化学特征

西秦岭温泉岩体是壳、幔岩浆混合的产物。寄主岩石(酸性端元)属铝过饱和钙碱性系列，贫CaO富FeOtotal,ANKC值大于1．1，NK／A均小于0．9，富Mo、Sn、Bi、W等高温热液成矿元素及Co、Nj、Cr等亲铁元素，LREE/HREE为10～15。基性端元暗色微细粒镁铁质包体及基性岩墙，富Na2O、K2O2而贫FeOtotal,异常富集轻稀土和Ba、Rb、Sr、Zr、Th、Hf、Nb等大离子亲石元素，而贫Co、Ni、Cr等亲铁元素，LREE/HREE为9．98～13，5，异常富轻稀土。由2端元岩浆混合形成的岩浆混合花岗岩，地球化学特征介于2端元间，并有显著的过渡特征和依从关系，反映了重要的岩浆混合信息。     

西秦岭党川花岗岩基的岩石化学特征

党川花岗岩基产于祁连与北秦岭造山带结合部位,由9个岩体组成,岩石普遍富K2O。志留纪为闪长岩-石英闪长岩,显著贫SiO2、Na2O,显著富MgO、CaO、TFeO、MnO、P2O5。泥盆纪-侏罗纪岩体为二长-正长花岗岩类,各岩体岩石化学特征较相似,高TiO2、K2O、Na2O,贫MgO、CaO,显示继承性演化规律。志留纪岩体的岩石化学构造环境判别及与其共生的早古生代火山岩相配套,是俯冲造山过程中的岛弧闪长岩类,而泥盆纪熊山沟岩体则是与之密切有关的造山期后陆缘或弧后花岗岩类。其余各岩体是本区造山后与大陆抬升作用以及大陆裂谷作用有关的花岗岩类。     

内蒙北山鹰嘴红山花岗岩体形成时代及构造环境分析

鹰嘴红山岩体位于内蒙古西部北山成矿带东段,岩性主要为黑云母二长花岗岩、似斑状黑云母二长花岗岩及钾长花岗岩。前人对该岩体的形成时代存在志留纪和泥盆纪的不同认识。笔者采用LA-ICP-MS锆石U-Pb定年获得似斑状黑云母二长花岗岩(423.1±1.5)Ma的年龄数据,表明二长花岗岩形成时代为中志留世。鹰嘴红山岩体属钙碱性高钾钙碱性,过铝质岩石系列;在原始地幔标准化蛛网图中,显示大离子亲石元素Rb、Th、K相对富集,高场强元素Ta、Nb、Zr、Ti相对亏损,Hf相对富集;REE总量较高,HREE微弱分异,LREE分异强烈;在球粒陨石标准化图上显示稀土元素呈右倾型配分模式,轻重稀土元素之间分馏程度较低,Eu强烈亏损(δEu=0.33～0.71)。结合花岗岩岩石成因类型研究和区域研究成果,认为鹰嘴红山花岗岩是在两侧陆块碰撞过程中大陆地壳加厚重熔形成的。     

北天山四棵树岩体地球化学特征及地质意义

四棵树岩体侵入于北天山蛇绿混杂岩带巴音沟蛇绿岩,属"钉合岩体"。通过对四棵树岩体进行详细的地球化学分析,该岩体主要组成为闪长岩、花岗闪长岩及二长花岗岩,SiO2含量为63.3%~68.9%,富碱,铁、镁、钙,钛含量较低,贫磷,具有偏铝质I型花岗岩特征。相对富集轻稀土而亏损重稀土,具明显铕负异常(δEu=0.4~0.7),富集大离子亲石元素K,Rb,Ba及Th,亏损高场强元素Nb,Ta,Zr及Hf。四棵树岩体可能来源于由洋壳和岛弧建造组成的年轻地壳,结合区域地质背景,认为该岩体形成的构造背景为后碰撞构造环境。     

北淮阳东段河棚岩体地球化学特征、LA-ICP-MS锆石U-Pb年龄及地质意义

河棚岩体位于北淮阳东段河棚地区,为似斑状细粒黑云钾长花岗岩,具较高的SiO_2和碱质含量,属于偏铝质碱性系列岩石。稀土元素含量中等,LaN/YbN与LREE/HREE值均较大,HREE相对于LREE明显亏损,Eu弱负异常,具较弱的Ce负异常,轻稀土分馏较明显,重稀土较平坦,属轻稀土富集型。岩石富集大离子亲石元素Rb、Ba、K和高场强元素Th、U、Ce、Zr、Hf,亏损Nb、Ta、Sr、Ti、P。通过LA-ICP-MS锆石U-Pb定年,获得河棚岩体206Pb/238 U年龄为128.6±2.1 Ma,表明该岩体形成于燕山晚期,是早白垩世早期岩浆活动的产物,代表河棚岩体的成岩年龄。主、微量元素地球化学特征表明河棚岩体属于非造山A型花岗岩,形成于燕山晚期伸展构造环境。     

甘肃天水坪道花岗岩体的地质特征及矿化信息

坪道岩体由早期到晚期可分出斜长花岗岩→花岗闪长岩→黑云二长花岗岩→含斑黑云二长花岗岩→正长花岗岩共5期岩浆活动。岩体碎裂化强,构造蚀变带发育。碱值(NK/A)为0 49～0 62,ANKC值大于1,见白云母,CIPW计算中多见刚玉,为钙碱性铝过饱和型。随SiO2含量增加,TiO2、FeO、MgO、CaO、Na2O均逐渐缓慢减少,而Fe2O3和K2O含量在剧增。岩石化学显示其源岩为上地壳杂砂岩类、碎屑岩类。岩体相对富集轻稀土,δEu值为0 35～0 7,铕亏损强烈。岩体贫Ba、Rb、Sr、Y、Cu、Zr、Ga、Ni元素,富Nb、Ta、Bi、Th、Cr、Sn、Mo、Hf、Au、Sc,异常富Hf、Sn、Sc、Au,数个构造破碎带及蚀变带有金矿化显示(0 2～0 4g/t),综合分析该岩体较有利于金矿的形成。     

西秦岭西段曲如沟花岗闪长岩年代学、地球化学特征及构造意义研究

曲如沟花岗闪长岩位于西秦岭造山带西段,侵位于中下三叠统隆务河组,主要岩性为灰白色细粒块状花岗闪长岩。岩石地球化学特征显示岩体具有高硅(66.08%~72.22%)、富钠(4.61%~5.01%)、准铝(A/CNK为1.04~1.11)高钾钙碱性I型花岗岩特征。岩体稀土总量为99.41×10-6~154.85×10-6,LREE=87.33×10-6~143.67×10-6,HREE=11.08×10-6~12.65×10-6,LREE/HREE值为7.23~12.85,具弱负Eu异常,在球粒陨石标准化稀土元素配分曲线图解上表现出轻稀土富集、重稀土显著亏损的特征。在原始地幔标准化微量元素蛛网图左端大离子亲石元素(Cs、Rb、Ba、Th)明显富集,曲线右端高场强元素(Nb、Ta、P)明显亏损,具有弧或碰撞型花岗岩微量元素特征。研究岩石成因表明岩石源区为下地壳变基性岩石,为岩石圈拆沉、幔源基性岩浆底侵导致下地壳变基性岩石部分熔融形成的产物,并发生了一定程度的壳幔岩浆混合作用。该岩体LA-ICP-MS锆石U-Pb年龄为(224.1±2.4)Ma(MSWD=2.4),形成于晚三叠世。结合区域资料,认为西秦岭造山带西段于印支晚期(224 Ma)古特提斯洋已经关闭,进入到后碰撞构造演化阶段。     

广西苍梧社洞钨钼矿床花岗岩类岩石的地球化学特征及其与成矿关系

广西苍梧社洞钨钼矿是与花岗岩类有关的矿床。矿区主要花岗岩类包括加里东期花岗闪长岩、花岗闪长斑岩和燕山晚期花岗斑岩。加里东期花岗闪长岩、花岗闪长斑岩具有低Si、K,富Na、Al和基性组分特征,属于强过铝质的正常钙碱性系列岩石;稀土总量低,轻重稀土分馏明显,弱负Eu异常(δEu=0.62~0.70);Ti、Nb、Ta亏损,Th、U、Pb、Zr、Hf富集,Rb/Sr平均值为0.78,明显富集W、Cu、Mo,属于I型花岗岩,为陆内造山带碰撞早期挤压背景下岩浆活动的产物,表现为对钨、钼、铜的成矿专属性。燕山晚期花岗斑岩具有高Si、K,贫Na、Ca和基性组分,属于强过铝质的高钾-中钾钙碱性系列岩石;稀土总量高,轻重稀土分馏不明显,强负Eu异常(δEu=0.03~0.06);Ti、Ba、K、Eu亏损,Th、U、Sm、Dy、Y、Ho、Yb、Lu富集程度更高,Rb/Sr平均值为7.56,明显富集Sn、Bi,属于燕山晚期岩浆演化程度较高的S型花岗岩,为碰撞后伸展环境的板内花岗岩,表现为对锡、金的成矿专属性。     

湘东邓阜仙二云母花岗岩锆石U-Pb年代学及地球化学研究

邓阜仙花岗岩体位于湖南茶陵县东北部,是一个由黑云母花岗岩、二云母花岗岩和白云母花岗岩组成的复式岩体。其中,二云母花岗岩与钨成矿关系最为密切。锆石LA-ICP-MS U-Pb同位素定年测得二云母花岗岩的加权平均年龄为154.4±2.2 Ma(MSWD=5.6,n=20),为燕山早期侵位。岩石地球化学研究表明,邓阜仙二云母花岗岩具有高硅、富碱、贫镁铁、强过铝质和高分异的特点。花岗岩相对富集大离子亲石元素Cs、Rb、K和高场强元素Th、U、Pb,亏损Ba、Sr和Ti等,稀土总量偏低(ΣREE平均值为90.59×10-6),轻稀土相对富集(LREE/HREE比值平均为9.97),铕负异常显著(δEu平均值为0.34),稀土元素配分模式呈右倾型。根据区域地质和花岗岩地球化学特征,确定岩石为S型花岗岩,形成于造山后伸展构造环境。     

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