泥盆系的亚阶——国际地层委员会泥盆系分会当前工作重点——泥盆系分会Bologna工作会议简介

第七届欧洲国际牙形刺会议１９９８年６月２３日至２７日在意大利Ｂｏｌｏｇｎａ大学与Ｍｏｄｅｎａ大学举行,此次会议是与国际地层委员会泥盆系分会工作会议和国际地科联国际对比计划４２１项目共同举行的。６月２３日下午专门举行了泥盆系工作会议,作为泥盆系分会的通讯委员,笔者参加了此次会议。国际地层委员会泥盆系分会的工作,可以说走在显生宙各系分会工作的前头。泥盆系各阶、阶的定义、阶的层型早已建立,对此笔者已作过专门介绍（王成源,１９９４）。虽然对个别的阶的定义和层型仍有争论（王成源,１９９８）,但泥盆系的年代…     

泥盆系法门阶四分已成定局

<正> 法门阶亚阶的划分是国际地层委员会泥盆系分会近年来讨论的重点(王成源,1994、2003)。德国早已组建了晚泥盆世亚阶划分的工作组,提出了德国的法门阶的划分方案。他们一致认为法门阶应当三分,即以早Palmatolepis marginifera带的底界为中法门阶的底界,早Palmatolepis expansa带的底界为晚法门亚阶的底界。比利时学者(Streel et al.,2002)极力主张法门阶四分,建立最晚法门亚阶,     

介绍国际泥盆纪地层委员会的几个决定

国际泥盆纪地层委员会(Subcommission on Devonian Stratigraphy,简称SDS)是国际地层委员会下属分会中最活跃的分会之一。在它的领导下,于1972年通过了志留一泥盆系界线的决定,在世界上建立了第一个界线层型。从理论、原则、方法上为其它地层界线的确立树立了样板。近几年来,SDS主要任务是解决泥盆系内部统与统,阶与阶间的界线,并已取     

国际三叠纪年代地层研究进展

简要概述了近年来国际三叠纪年代地层等方面所取得的一些重要进展:国际地层委员会三叠系分会已于上世纪90年代确定将三叠系划分为3统7阶,但至今仅确定了三叠系底界一个“金钉子”,安尼阶-拉丁阶界线层型有望在近期内被最后确认,而其他5条界线仍在加紧工作中;随着同位素测年技术和手段的不断改进,三叠纪一些重要的年代地层界线的地质年龄也在不断更新;亚阶虽然不是国际三叠系研究的重点,但亚阶的划分也是三叠纪年代地层研究的重要方面,尤其在下、中三叠统研究中已有较好的基础;以脊椎动物为基础的陆相三叠纪年代地层划分方案有待在推广应用中得以完善。全国地层委员会于2 0 0 0年提出了3统6阶的中国海相三叠系划分方案和3统7阶的中国陆相三叠系划分方案,为启动中国三叠纪年代地层学奠定了基础。     

国际泥盆系GSSP与华南泥盆系划分

简要介绍国际泥盆系各阶界线定义、界线层型,以及目前进行的国际泥盆系埃姆斯阶、吉维阶、弗拉斯阶和法门阶亚阶划分的情况,并讨论了中国区域性阶与国际性阶之间的关系:除了埃姆斯阶和法门阶在华南分别进一步细分为郁江阶和四排阶以及锡矿山阶和邵东阶等外,那高岭阶、应堂阶、东岗岭阶和佘田桥阶大致分别相当于布拉格阶、艾费尔阶、吉维阶和弗拉斯阶;今后需加强对上述几个中国区域性阶底界确切时代的研究。国际泥盆系中各亚阶在我国大体可以应用,但吉维阶中亚阶-上亚阶、弗拉斯阶下亚阶-中亚阶的分界及最上法门亚阶的底界在华南台地相区岩石地层上不易划分。     

二叠系全球界线层型和点位(GSSP)研究进展

新的二叠纪年代地层系统为国际二叠系分会通过并正式纳入“国际地层表”后,已有5个GSSP得到正式批准,它们分别是阿瑟尔阶(二叠系)、吴家坪阶、卡匹敦阶、沃德阶和罗德阶的底界。长兴阶底界的GSSP提案在国际二叠系分会投票中,以94 %赞成票通过,并交国际地层委员会进行投票表决。国际二叠系分会最近的主要工作重点将是早二叠世乌拉尔统内空谷阶底界、亚丁斯克阶底界和萨克马尔阶底界的确定工作,由B.I.Chuvashov领导的界线工作组正在对俄罗斯乌拉尔南部的界线剖面进行工作。国际二叠系分会力争在2 0 0 6年底前完成投票工作,并使二叠纪的地层研究全面转入国际间对比等层型后研究     

“国际地层表”与GSSP

近年来,“国际地层表”不断被国际地层委员会更新,用GSSP来定义年代地层单位而建立起来的“国际地层表”,使得大家在叙述地质历史时有一种共同的语言、有一个全球性的标准。在显生宇的96个阶(统)中已有4 6个阶(统)确立了GGSP,其余的有望在2 0 0 8年全部确立。我国已取得了4枚金钉子,即将取得3枚,还有可能再获得4—6枚。根据区域特点,我国已编制了“中国区域年代地层(地质年代)表”并正在开展区域性建阶工作     

三叠纪年代地层与中国建阶

国际地层委员会三叠系分会(SubcommissiononTriassicStratigraphy,简称STS)成立后的第一件工作就是建立全球统 一的三叠纪年代地层划分方案.以国际地质对比规划项目IGCP-4(特提斯地区的三叠系)所取得的研究成果为基础,经过STS 专家的深入研讨,采用投票表决的方式于1991年确定了将三叠系划分为3统7阶的国际年代地层格架.随后的焦点集中于各 阶界线层型剖面和点位(GlobalStratotypeSectionandPoint,简称GSSP)的选定工作.但时至今日只确定了3个阶的GSSP,而 且只有三叠系底界,即印度阶底界的GSSP获得的研究最多,且应用广泛;另外2个阶(拉丁阶和卡尼阶)底界的GSSP仍以传 统的菊石作为首选定义标志,其推广可应用性还待实践检验.其他4个阶的界线层型选定工作正在推进中,但都存在一些困 难,其中尤以奥伦尼克阶界线层型的选定工作面临重大挑战.鉴于国际年代地层研究工作所面临的困境,全国地层委员会组织 专家于2000年提出了中国的年代地层划分和建阶方案,并在全国范围开展研究和推广应用.由于三叠纪时期中国处于从海向 陆的重要转折时期,海、陆相地层在中国都有广泛发育,因此提出了海、陆相两套中国三叠纪年代地层划分和建阶方案.经过十 多年的建阶研究和应用实践,中国三叠纪年代地层建阶方案逐步得以改进和完善,促进了中国三叠纪地层规范化研究,为相 关科学研究和实践应用奠定了基础,也推动了国际相关领域的科学研究.      

全国地层委员会召开三届四次常委扩大会议

20 0 2年 7月 2 3日至 2 5日在北京香山饭店召开了全国地层委员会三届四次常委扩大会议 ,主要内容有 :1)关于 2 0 0 1年度全国地层委员会工作情况的汇报 (王泽九副主任 ) ;2 )“中国主要断代地层建阶研究”项目各课题组汇报研究进展情况及下步工作计划安排 ;3)审查修改已完成的《中国区域年代 (地质年代 )表》说明书 (初稿 ) ;4 )审查已编制完成的《中国地层典》(中文电子版 )。此次会议的会议纪要将在下期另行刊出。全国地层委员会召开三届四次常委扩大会议@边步     

关于中国的海相三叠系建阶及下三叠统分阶界线

国际地层委员会提出将在近年内完成各地质年代中阶间界线层型的选定工作.全国地层委员会也于第3届全国地层委员会上提出了中国各时代地层的建阶方案.因此, 以阶为实体的年代地层学研究已成为当前地层学研究的焦点.介绍了国际三叠系年代地层划分方案及确定过程, 并列述了中国海相三叠系建阶方案.重点讨论了中国海相下三叠统各阶顶、底界线及其确定标准和标志, 提出了中国下三叠统建阶工作研究重点      

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.     

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.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861