徐州-宿州地区中生代埃达克质岩石岩浆起源深度的限定--深源捕掳体温度-压力条件证据

徐州—宿州地区中生代侵入杂岩主要由二长闪长斑岩—闪长岩—二长岩组成,属钙碱性系列。岩石地球化学特征与典型埃达克岩极为相似,可称之为埃达克质岩石。该类侵入杂岩中含有较多的榴辉岩类和石榴片麻岩类深源岩石捕虏体及石榴子石残留晶。深源岩石捕虏体的岩相学研究表明,榴辉岩类捕虏体在遭受榴辉岩相变质之后,又经历了角闪岩相退变质,然后被寄主岩浆所捕获。矿物平衡温压计算结果表明,榴辉岩相变质的温度条件为：608～766℃。角闪岩相退变质的温度、压力条件分别为：523～800℃,0．50～0．98GPa。由此可以判定本区中生代侵入杂岩母岩浆的起源深度应在20～34km之间,即岩浆起源于深部地壳。     

桐庐、相山火山-侵入杂岩单颗粒锆石U-Pb年龄

利用单颗粒锆石Ｕ－Ｐｂ法分别测定了桐庐和相山火山－侵入杂岩中早期及晚期形成的岩石单元的结晶年龄,桐庐杂岩体中早期火山岩的喷发年龄为１３４．９Ｍａ,晚期浅成岩的结晶年龄为１３４．４Ｍａ,杂岩体基本上属于同时形成,为早白垩世岩浆活动的产物;相山杂岩体中第二阶段岩石的结晶年龄为１４０．３Ｍａ,最晚阶段超浅成岩的结晶年龄为１３５．４Ｍａ,杂岩体各单元的形成时间相近,为晚侏罗世末期岩浆活动的产物。可见利用单颗粒锆石Ｕ－Ｐｂ年龄能非常有效地讨论一套岩石组合是否是同时间形成的,而这正是火山－侵入杂岩研究的重要内容之一。     

鲁西地区接触交代（矽卡岩）型铁矿成矿机制——以济南地区为例

鲁西地区接触交代（矽卡岩）型铁矿主要分布在沂沭断裂带西侧鲁中隆起区济南、莱芜、金岭、潘店等地。济南地区铁矿资源丰富,亦是鲁西四大接触交代型铁矿成矿区之一。铁矿床形成于中生代燕山晚期中偏基性侵入杂岩与奥陶纪马家沟群碳酸盐岩的接触带上。济南地区杂岩体受齐广断裂控制,铁矿体在空间上严格受接触带的控制。通过岩石学、岩石化学、地球化学等分析,结合精细锆石LIMS U-Pb测年,发现济南地区中生代侵入杂岩形成时代约为130 Ma,属早白垩世燕山晚期,岩石类型具有同源岩浆演化特征;岩浆活动过程中有早期壳源物质参与,原始母岩浆来源于上地幔与下地壳,是在源区与早期拆沉的下地壳物质混合熔融所形成的产物。鲁西地区中生代燕山晚期侵入杂岩体源岩及围岩为铁矿提供铁质及矿化剂并提供热动力条件,各类构造为矿液运移提供通道及容（储）矿空间,接触交代变质为成矿提供动力条件,从而在该地区形成接触交代（矽卡岩）型铁矿。     

安徽铜陵新桥铜-硫-铁矿床矶头岩体的矿物学和锆石U-Pb年代学及其地质意义

长江中下游成矿带铜陵矿集区内的许多矿床皆与中生代岩浆岩的侵入密切相关,选取新桥矿床矶头岩体为研究对象,进行LA-ICP-MS锆石U-Pb定年以及岩体地质和矿物学研究。锆石的高Th/U比值特征及典型岩浆锆石环带显示其为岩浆成因。矶头岩体中主体石英闪长岩16个测点的加权平均年龄为(141.6±1.1)Ma,后期侵入的闪长玢岩20个测点加权平均年龄为(129.95±0.6)Ma。两者均形成于早白垩世,矿区内岩浆活动至少有两期,主岩浆作用为141 Ma。矶头岩体是由幔源岩浆上侵至13~15km中地壳先形成深部岩浆房,发生结晶分异和同化混染,随后在构造扰动与岩浆脉动下,深部岩浆房中的岩浆沿构造薄弱面上侵至7~8km,冷凝固结形成,其结晶温度大约为800℃。矶头岩体约束成矿时代及成矿作用,新桥矿床经由高温热液交代作用,并经后期热液多次叠加改造成矿。     

山西省繁峙县后峪铜钼金矿锆石形态标型特征

为探讨后峪地区锆石的生长条件及其与该地区岩浆岩的成因和演化的关系,对本区不同岩体中的锆石形态标型进行了系统的研究。结果表明:不同岩体中锆石的长宽比大多集中在1.5∶1~3∶1之间,按Pupin锆石晶体类型分类,岩体中的锆石可划分为R2、P1-5、S2-5、S7-10、S12-15和S20等类型,说明锆石是在碱质岩浆中结晶,且结晶温度较低;岩体的液相线的温度为850~750℃,锆石大规模结晶温度为700~650℃。锆石的结晶作用从岩浆早期开始一直持续到岩浆后期,温度跨度大,持续时间长,说明岩浆为富水岩浆,有利于斑岩型矿床Cu-Mo-Au的矿化。本区岩浆岩的化学成分分析及不同岩体中锆石群类型的演化趋势图表明:本区岩浆除了壳源成因之外还有幔源成分加入其中,岩浆岩属于钙碱性系列(偏碱性)岩石。     

太行山中段麻棚岩体花岗岩类岩石副矿物成因矿物学研究

通过对麻棚岩体花岗岩类岩石主要的副矿物组合(磁铁矿、榍石、磷灰石、锆石等)和相应的含量以及矿物的形态、成分,特别是花岗岩中330粒和石英闪长岩中316粒锆石群形态学的研究,结合岩相学特征,探讨了花岗岩的成因、岩浆演化及其与金矿化的关系。确定麻棚岩体为岩浆成因,岩浆物质组成以壳源为主,有幔源物质混入,为Ⅰ型花岗岩;副矿物在相对氧化环境下结晶,锆石在900℃～600℃范围内结晶。锆石结晶温度跨度大以及斑晶具有黑云母等含水矿物,表明侵位前岩浆富含水分;锆石结晶温度的峰值变化以及岩石的斑状结构表明,岩浆在侵位时曾经发生过不同程度的气—液分离。岩浆结晶过程中的相对氧化环境和岩浆的气—液分离对金矿的成矿作用具有重要意义。     

大兴安岭北部塔河花岗杂岩体的地球化学特征及成因

塔河杂岩体位于塔源-喜桂图缝合带北侧的额尔古纳地块东部,是早古生代侵入的花岗杂岩体。该杂岩体的主要岩石类型为正长花岗岩、二长花岗岩,少量碱长花岗岩和花岗闪长岩,辉长岩以包体存在于花岗岩中。岩石成因类型为典型的Ⅰ型后造山侵入体。岩体在野外地质特征、矿物组合、显微结构、化学成分及锆石Hf同位素特征等方面都表现出岩浆混合成因。在早古生代额尔古纳地块与兴安地块拼合后的后造山伸展拉张背景下,地壳和地幔都发生部分熔融,直接起源于亏损地幔的玄武质岩浆侵入到下地壳熔融的花岗质岩浆房,经结晶分异作用,形成了塔河杂岩体不同的岩石类型。花岗岩的εHf(t)为-0.8~+5.6之间,Hf模式年龄在0.9~1.5Ga之间,反映塔河花岗岩的源岩应该是在中-新元古代时期由亏损地幔起源的新生地壳物质。结合额尔古纳地块早古生代和中生代花岗岩锆石Hf同位素资料,我们认为额尔古纳地块在中-新元古代时曾发生过一次重要的地壳增生事件。     

华南桂东南地区加里东期Ⅰ型花岗岩类的岩石成因及构造意义

龙新岩体和夏郢岩体位于扬子地块与华夏地块拼合带的西南端,岩体中的Ⅰ型花岗岩成因研究对揭示桂东南地区早古生代的地球动力学背景及其构造演化具有重要的地质意义.对龙新岩体的寄主岩和其暗色微粒包体,以及夏郢岩体岩石进行了LA-ICP-MS锆石U-Pb定年、Lu-Hf同位素和全岩地球化学研究.锆石U-Pb定年结果显示,龙新岩体的寄主岩（花岗闪长岩）的年龄为440±2 Ma;龙新岩体的暗色包体（闪长岩）的年龄为441±1 Ma,寄主岩与暗色包体为同期岩浆作用的产物.夏郢岩体花岗闪长岩和二长花岗岩年龄分别为447±3 Ma和436±3 Ma,说明夏郢岩体至少发生了2期岩浆侵入事件.Hf同位素研究表明,龙新岩体寄主岩和暗色微粒包体的锆石ε_Hf（t）值分别为-3.32~-5.83和-17.89~-1.82,二阶段模式年龄（T_DM2）分别为1.62~1.76 Ga和1.57~2.54 Ga;夏郢岩体早期花岗岩闪长岩和晚期二长花岗岩的锆石ε_Hf（t）值分别为-15.43~3.03和-4.79~6.82,T_DM2分别为1.59~1.99 Ga和0.97~1.70 Ga,指示物源主要来自古-中元古代的地壳物质.地球化学特征表明龙新岩体寄主岩为准铝质高钾钙碱性Ⅰ型花岗岩,寄主岩和暗色微粒包体均富集轻稀土元素和大离子亲石元素,亏损重稀土元素及高场强元素;夏郢岩体早期的花岗闪长岩为弱过铝质高钾钙碱性Ⅰ型花岗岩,晚期的二长花岗岩则为强过铝质高钾钙碱性Ⅰ型花岗岩,主微量元素特征均与龙新岩体寄主岩相似.根据研究区花岗岩和镁铁质包体的岩相学、年代学、地球化学及Hf同位素组成特征,表明龙新岩体的暗色包体（闪长岩）为岩浆混合成因,而龙新岩体寄主岩（花岗闪长岩）和夏郢岩体（早期花岗岩闪长岩和晚期二长花岗岩）具有一致的岩石源区和岩石成因,但在后期的成岩过程中存在岩浆混合和结晶分异程度的差异.综合以往对华南地区构造背景的研究,认为龙新和夏郢岩体是在扬子地块和华夏地块陆内造山期后,岩石圈伸展减薄,热的幔源岩浆上涌底侵,中-下地壳受到地幔热影响发生部分熔融,形成的酸性岩浆在源区和基性岩浆经历了不均一且不强烈的壳-幔混合作用形成的.      

南京蒋庙岩体的年代学、地球化学及其地质意义

南京蒋庙侵入岩体的主体为辉长岩-闪长岩,并伴有少量的二长岩。LA-ICP-MS锆石U-Pb定年表明,其形成于118±1.1Ma,为长江中下游地区中生代最晚的一次岩浆活动。岩石地球化学资料表明,在岩浆上升及结晶过程中无明显的地壳物质混染。蒋庙岩体的εNd(t)值为-0.49～-2.29,介于DMM及EMII之间。简单二单元混合计算表明,其源区中有较高比例的软流圈物质加入。综合其它年龄资料,长江中下游地区中生代岩浆活动可分为3期:早期为151～133Ma,中期为131～126Ma,晚期为125～118Ma。中生代时期该区总体处于板内伸展的构造环境,经历了岩石圈拉张、软流圈持续上涌的地幔过程。     

云南鸡街碱性超基性岩杂岩体岩浆过程模拟

在已有云南鸡街碱性超基性杂岩体地质、地球化学资料基础上，本文利用岩石学混合计算等方法对杂岩体源区成分、结晶分异过程进行模拟。结果表明，鸡街杂岩体来源于亏损地幔；岩体中相对早期碱性超基性岩（主体岩石：霞霓纳辉岩、霓霞岩和磷霞岩）为很少或没有受到上部地壳物质污染的幔源岩浆结晶分异作用产物；晚期碱性中性岩（脉岩：钠霞正长岩和霓辉钠长斑岩）为幔源岩浆（与碱性超基性岩同源）演化过程中发生岩浆液态不混淆作用产物。     

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