甘肃永登石灰沟奥陶纪岛弧区沉积建造的特征

长期以来众自然地把岛弧与火山活动联系起来，认为无火山喷发、无火山建造和火山沉积建造就不能称其为岛弧，火山活动无可非议的被认为是判别岛弧的首要标志。火山熔岩及火碎屑岩，自然地成为岛弧区建造的一个必然组成部分。但应予注意的是，火山岩和火山碎屑岩是不是岛弧区建造序列中的唯一成员，这一问题在国内、外该领域的研究中未被引起重视。笔者在我国西北地区的重要造山带之一－北祁连早古生代造山带，进行了较深入的工作并获     

东天山古生代板块构造特点及其演化模式

东天山的古板块构造格局主要由塔里木陆壳板块、西伯利亚陆壳板块和哈萨克斯坦洋壳板块在古生代的活动所奠定的。在古生代，东天山的板块构造格局主要表现为多列岛弧及其间弧间盆地和弧后盆地的形式。自北而南依次发育：博格达－哈尔里克泥盆－石炭纪岛弧，吐哈弧间盆地，觉罗塔格泥盆－石炭纪岛弧，吐哈弧间盆地，觉罗塔格泥盆－石炭纪岛弧，中天山志留－石炭纪岛弧，南天山－红柳河弧后盆地和北山陆缘裂谷带。其主要成因是由于准噶尔洋壳板块向塔里木陆壳板块下俯冲，俯冲带不断后退所形成的。奥陶纪中后期，中天山由塔里木北缘分出，形成具有古老陆块基底的类似于现今日本列岛的中天山岛弧。在其后形成南天山－红柳河弧后盆地和北山陆缘裂谷带。泥盆纪早期，俯冲带后退至觉罗塔格北侧形成觉罗塔格岛弧。泥盆纪晚期，俯冲带后退至博格达－哈尔里克北缘，形成博格达－哈尔里克岛弧。中石炭世至早二叠世，博格达同准噶尔陆块碰撞造山，哈尔里克同麦钦乌拉岛弧碰撞造山。与此同时，南天山－红柳河弧后盆地和北山裂谷带也相继闭合，而吐哈弧间盆地则成为未被消减完的弧间盆地残留下来。东天山古生代板块演化可与现今印度尼西亚地区的板块演化相类比。     

云南中甸雪鸡坪和普朗斑岩铜矿容矿斑岩的地球化学特征

中甸岛弧是中国西南三江构造火成岩带中义敦岛弧的组成部分,位于义敦岛弧的最南端,其东部和南部是甘孜-理塘板块缝合带,西部是乡城-格咱深大断裂[1-2].     

东秦岭陡岭古岛弧和武当古弧后盆地及其地质意义

丹凤－信阳蛇绿混杂带作为秦岭－大别碰撞造山带主缝合带，其南部属于扬子板块北部大陆边缘。研究区域位于东秦岭南翼，是扬子板块北部大陆边缘的一部分。①晚元古－中震旦世，扬子板块北缘为活动型大陆边缘，发育陡岭岛弧和弧后盆地；②晚震旦－－早古生代，扬子板块北缘转为被动型大陆边缘，陡岭岛弧构成边缘地块，武发古弧后盆地演化为边缘盆地；③早古生代晚期，华北板块南缘的秦岭岛弧首先与扬子板块北缘的陡岭国缘地块（古岛弧     

论岛弧的拱结构

基于海沟－岛弧－弧后盆地体系起伏变化的地壳厚度和岛弧平面上独特的延展方式，从结构力学上看，岛弧实质上是横跨于汇聚板块边界上的二铰拱，弧体及两端支点的地质构造特点都说明了这一点。板块俯冲边界上作用力的方式和方向相当于作用在二铰拱上的竖向均布载荷，因而岛弧选择的合理拱轴为抛物线。为了保持汇聚板块边界的平衡，岛弧呈抛物线形向外扩展，引起弧后盆地向岛弧一侧的扩张，这与大洋中脊的扩张有本质的不同。     

巴基斯坦北部科希斯坦弧奇拉斯杂岩体的地质及地球化学特征

位于巴基斯坦北部西喜马拉雅的科希斯坦地体为夹持于亚洲板块与印度板块之间的倾斜的岛弧型壳体。科希斯坦岛弧北界为主地幔逆总断层（MMT），北界为北部缝合带（或喀啦昆仑主逆冲断层，MKT），可将其划分为几个地质单元。奇拉斯（Chilas)杂岩体为一长约300km、宽50km的巨型基性侵入岩体，与MMT和MKT近平行展布。它被认为是科希斯坦岛弧的岩浆房根区。奇拉斯杂岩体主要由辉长苏长岩和几个超镁铁质岩－镁铁质岩（简称UMA）岩体组成。前侵入后之中。奇拉斯杂岩体岩石普遍发生轻微变形，出现叶理化和韧性剪切带。UMA主要由橄榄石（含或不含单斜辉石）堆积岩（纯橄岩，异剥橄岩）和斜长石－单斜辉石－斜方辉石堆积岩（二辉辉长岩）组成，含有少量单斜辉石－斜方辉石堆积岩（辉石岩）。辉长苏长岩的地球化学特征表明其为岛弧环境下形成的非堆积岩，而UMA的地球化学特征表明其为岛弧环境下的堆积岩。辉长苏长岩和UMA的主元素地球化学特征在AFM图解上可用堆积和非堆积的模式来解释，辉长苏长岩的稀土和微量元素地球化学特征在100MgO/(MgO TFeO)图解上显示岛弧型特点，且UMA表明其堆积特性。     

三江中北段弧—盆格架与地质构造演化

弧—盆体系中岛弧与弧后盆地相间并存是一大特色。本文以昌都地区三叠纪弧—盆格局为例 ,阐明了岛弧、弧后盆地与夹于其间的微陆块等地质特征 ;划分出 2个构造演化阶段 ,一是早中三叠世江达—阿中岛弧与弧后盆地的发育 ,二是晚三叠世滞后型岛弧与生达残留弧后盆地的形成 ,并揭示了其演化的动力学。     

北山北带地质构造特征

甘肃北山地区主体属塔里木板块的北缘其内部可划分出北、中、南三个构造带，北带主体为加里东期岛弧带，北山地区于古生代经历了弧－盆体制及裂陷槽的活动大陆边缘的发展，总体上经历了前寒武纪古陆形成阶段，加里东期岛弧及陆缘裂陷－闭合阶段，海西期岛弧期后构造－岩浆活动及陆壳再次裂陷－闭合阶段和中、新生代差异断块升降阶段。     

东秦岭丹凤岩群的形成时代和构造属性

东秦岭丹凤岩群位于秦岭商丹构造带上，主体形成于新元古代（1000Ma-800Ma)，其中变质基性火册岩的岩石地球化学特征表明为岛弧型火山岩系，而非蛇绿岩，其形成于秦岭造山带新元古代主造山期板块构造体制下的活动陆缘古岛弧构造环境。     

三江中北段弧一盆格架与地质构造演化

弧－盆体系中岛弧与弧后盆地相间并存是一大特色。本文以昌都地区叠纪弧一盆格局为例,阐明了岛弧、弧后盆地与夹于其间的微陆块等地质特征;划分出２个构造演化阶段,一是早中三叠世江达－阿中岛弧与弧后盆地的发育,二是晚三叠世滞后型岛弧与生达残留弧后盆地的形成,并揭示了其演化的动力学。     

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