龙门山北段志留纪地层研究

作者通过对龙门山北段志留纪牙形石和笔石的研究,自下而上初步建立了该区的牙形石带:Paraspothognothodus obesus 带,Paraspothognathodus parahassi-P．guizhoweusis 组合带,Pterospathogwa-wodus oelloui 带:笔石带:Demirastriles (?) 带,Spirograptus (?) 带和 Streptograptus nodifer 带.在此基础上,将该区地层自下而上划分为:龙马溪组、磨刀垭组、后蒿坪组和宁强组,其中磨刀垭组和后蒿坪组为2个新建组。本区绝大部分地层为下志留统,只有宁强组上部可能为中志留统。     

安徽巢湖平顶山下三叠统牙形石生物地层序列

简要介绍安徽巢湖平顶山下三叠统牙形石生物地层研究的最新成果.对平顶山西坡剖面112.8 m厚的下三叠统地层所采集的286件牙形石样品, 经处理后获得2 870余枚牙形石样本, 经鉴定共有11属51种.这些属分别是Hindeodus, Isarcicella(?), Neogondolella, Neospathodus, Platyvillosus, Cratognathodus, Parachirognathus, Pachycladina, Ellisonia, Aduncodina和Cornudina.牙形石生物地层从老到新可划分为9个牙形石带: (1)Hindeodus typicalis- Neogondolella planata带; (2)Neogondolella krystyni带; (3)Neospathodus kummeli带; (4)Neospathodus dieneri带; (5)Neospathodus n. sp. C- Neospathodus n.sp. D带; (6) Neospathodus waageni带; (7)Neospathodus n.sp. M带; (8)Neospathodus eotriangularis带; (9) Neospathodus abruptus- Neospathodus homeri带.牙形石的组合面貌基本可与国内外其他地区牙形石带相对比.但其中牙形石(2), (3), (5), (7), (8)带为巢湖地区首次建立.在下三叠统菊石带控制下所建立的连续的牙形石分带对全球的三叠系阶的对比具有十分重要的意义. 关键词: 牙形石; 牙形石生物地层; 下三叠统; 安徽巢湖.      

鲁西地区寒武纪原始真牙形石分类方案的探讨

鲁西地区晚寒武世地层发育，产有数量丰富、分异度大的原始真牙形石分子，经笔者研究，建立了2新属、2新种及2未定种Camconodontus rotundatus geo et sp．nov．，Camconodontus sp．，Laiwunodus lateronodus gen et sp．nov．，Laiwunodus sp．；对Das ytodus属进行了补充修订，建立了1新种Dasytodus posteronodus sp．nov．。这些属种的建立丰富了对已有原始真牙形石概念的认识。基于内部构造的观察，对原始真牙形石及部分易混淆的副牙形石进行正确的分类。以此为基础，分析、总结了这些分子外部形态上的差异，选用的分类原则和标准是从一般到特殊、特征明显程度逐渐降低，划分出了三类原始真牙形石和一类副牙形石，这在很大程度上简化了早期真牙形石分类研究的复杂性，为早期真牙形石的深入研究奠定了基础。     

塔里木盆地亚科瑞克剖面奥陶系牙形石生物地层初步研究

塔里木盆地西北缘乌什县东南亚科瑞克剖面奥陶系发育，并且该剖面也是塔里木盆地上奥陶统沉积最为齐全的露头剖面之一，尤其是上奥陶统的中—上部发育了许多重要的牙形石属种。本文通过对剖面上灰岩层样品的系统采集和牙形石分析鉴定，将该剖面的奥陶系分为4个牙形石组合和2个牙形石带。自下而上依次为：Serratognathus diversus - Bergstroemognathus extensus 组合 , Protopanderodus calceatus - Periodon aculeatus 组合 ,A phelognathus sp. - Tasmanognathus sp. 组合, Belodina confluens- Phragmodus undatus 组合 , Yaoxianog-nathus neimengguensis 带和 A phelognathus pyramidalis带。其中，上奥陶统上部牙形石的重要属种A. pyramida-lis、A. politus、Y. yaoxianensis 和 A. neimengguensis以及上奥陶统上部的A．pyramidalis带与Y．neimengguensis带是首次在柯坪地层分区发现。这些发现初步解决了塔里木盆地覆盖区与露头区上奥陶统不能进行精细生物地层对比的问题。     

浙江长兴地区二叠纪与三叠纪之交牙形石动物群及地层意义

本文把采自华南浙江长兴煤山二叠系与三叠系界线剖面的牙形石动物群从老至新分为三个带:1.Gondolella subcarinata-G·wangi组合带;2.G.changxingensis-G.deflecta组合带;3.Anchignathodus parvus带。将煤山剖面的二叠系与三叠系界线划在2、3组合带之间。并初步探讨了长兴地区长兴期至早格里斯巴赫期的牙形石分异度与沉积环境变迁。     

贵州册亨中三叠统坡段组中上部石珊瑚及牙形石生物地层

为进一步精确限定黔西南中三叠统坡段组的地质时代,论文选择贵州册亨中三叠统坡段组典型剖面开展了石珊瑚及牙形石生物地层研究,在中三叠统坡段组(中上部)识别出石珊瑚3属3种,它们包括Pentasmilia zaitingnaensis,Pinacophyllum spizzensis,Gillastraea delicate;识别出牙形石Neogondolella constricta带。该带除含有带分子外,还含有Neogondolella bulgarica,Neogondoela navicula,Neogondolella acuta,Neogondolella alpina alpina,Cratognathodus kochi,Ozarkodina tortilis,Prioniodinasp.,Lonchodinasp.等重要牙形石。通过对牙形石特征的分析和国内外同名带的对比,认为坡段组Neogondolella constricta带大体可与贵州省盘县地区羊圈-楚皮凹剖面中三叠统关岭组上段、贵州罗甸关刀(2)剖面关刀岩楔、和云南开远马者哨法郎组的同名化石带对比,进而确定贵州册亨地区坡段组含牙形石Neogondolella constricta带的地层时代为安尼期的Illyrian亚期。     

中国三叠纪牙形石的古生物地理分区

本文根据中国三叠纪牙形石的地理分布、属种的分异度和特征属种的丰度，将中国三叠纪牙形石归属Kozur(1973)的特提斯生物大区亚洲生物省，在早-中三叠世，进一步二分为喜马拉雅生物亚省和华夏特提斯生物亚省，后者三分为西华夏特提斯生态区、东华夏特提斯生态区和右江生态区。在晚三叠世时，右江生态区已不复存在。     

祁连山中寒武统牙形石

青海大通中寒武统毛家沟群产丰富的牙形石，共有７属８种，以原牙形石占优势，而副牙形石仅有少数个体。与华北和华南相比，这一组合所含副牙形石的比重明显降低，而且缺乏等类型。     

三叠纪牙形石的古环境与古地理意义

牙形石广泛分布于寒武纪至三叠纪的海洋里。三叠纪牙形石的种类、形态、大小和产出频率受海水盐度、深度、温度和水动力条件等因素控制，不同的牙形石生态特征即牙形石相反映不同的沉积环境，所以，根据三叠纪牙形石相和牙形石特征属种的丰度，不但可区分三叠纪不同的沉积相区（台地相区、台地边缘相区、盆地相区），恢复三叠纪古地理面貌，而且可划分出牙形石生物地理区。中国早三叠世牙形石归属特提斯生物大区亚洲生物省，并可进一步划分出两个生物亚省和若干生态区。     

陕西凤县石炭系牙形石组合及其时代

陕西凤县核桃坝剖面含２个牙形石组合，下组合为Ｇｎａｔｈｏｄｕｓｔｙｐｉｃｕｓｓ－Ｓｉｐｈｏｎｏｄｅｌｌａｃｆ．ｉｓｏｓｔｉｃｈａ组合，相当ｔｙｐｉｃｕｓ带和ｉｓｏｓｔｉｃｈａ－上ｃｒｅｎｕｌａｔａ带，属杜内阶；上组合为Ｉｄｉｏｇｎａｔｈｏｄｕｓｄｅｌｉｃａｔｕｓ－Ｎｅｏｇｏｎｄｏｌｅｌｌａｃｌａｒｋｉ组合，其时代为维斯发早期。本文共描述了１５个牙形石种，并讨论了Ｎ．ｃｌａｒｋｉ等３种的个体发育。     

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.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)