云南早期有颌类化石形态学研究新进展

有颌类的出现是脊椎动物演化历史上的里程碑,云南是世界早期有颌类研究的最重要的地区之一。云南的盾皮鱼类包含在节甲鱼类、瓣甲鱼类、胴甲鱼类三大类群和向硬骨鱼类的过渡类群中,硬骨鱼类以肉鳍鱼类为主,棘鱼类、软骨鱼类和部分硬骨鱼类呈微体化石保存。云南早期有颌类化石的形态学研究已经历了56年,本文回顾总结发现于云南、分布在5个动物群16个组合中的75属82种早期有颌类的整体形态学特征,并展望云南早期有颌类化石未来的研究方向。     

陕西北部三趾马红粘土成土碳酸盐碳、氧稳定同位素特征及所记录的古气候演变

陕西府谷王大夫梁三趾马红粘土剖面中成土碳酸盐碳、氧稳定同位素分析及其变化曲线表明，三趾马红粘土形成于半干旱到半湿润气候条件下，且已出现类似于黄土中古季风特征的干热－温湿的旋回性变化，并在晚期有周期缩短、幅度加强的趋势．结合地层中的物质组成及古哺乳动物群性质的变化，陕西北部新第三纪晚期古气候经历了干热－温湿－干热的演化历史，植被以草原疏林为主，气候适宜期曾出现半湿润森林景观     

黄河中游三趾马红粘土的岩石学研究及古气候意义——以陕西府谷老高川三趾马红粘土剖面为例

将岩石学研究方法引入三趾马红粘土研究中,利用薄片系统观察、电镜扫描、Ｘ－射线衍射、粒度分析及化学分析手段,对红粘土的岩石学、微结构及形态学进行较为细致的研究。结果表明,各粘土层下部的沉淀层系成壤过程中钙质从上部土壤中淋滤并向下迁移再沉淀的结果。土壤中粘化层的光性定向粘粒及淀积铁质粘胶膜的发育程度受古气候及淋滤作用强度的控制。红粘土形成过程中主要为干旱、半干旱－半湿润气候的草原疏林环境,也有湿润气候的森林环境出现。府谷老高川三趾马红粘土剖面记录了四个大的气候旋回     

黄河中游三趾马红粘土的岩石学研究及古气候意义--以陕西府谷老高川三趾马红粘土剖面为例

将岩石学研究方法引入三趾马红粘土研究中,利用薄片系统观察、电镜扫描、Ｘ－射线衍射、粒度分析及化学分析手段,对红粘土的岩石学、微结构及形态学进行较为细致的研究。结果表明,各粘土层下部的沉淀层系成壤过程中钙质从上部土壤中淋滤并向下迁移再沉淀的结果。土壤中粘化层的光性定向粘粒及淀积铁质粘胶膜的发育程度受古气候及淋滤作用强度的控制。红粘土形成过程中主要为干旱、半干旱－半湿润气候的草原疏林环境,也有湿润气候的森林环境出现。府谷老高川三趾马红粘土剖面记录了四个大的气候旋回     

陕西北部三趾马红粘土的形成环境

多种地质资料表明,陕西北部的三趾马红粘土主体形成于半干旱草原疏林环境中。5.3 Ma B.P左右所对应地层记录了半湿润森林景观。红粘土形成期间古气候周期性波动是其重要特征之一,使得淋溶粘土层与钙质淀积结核层交替出现。化石埋藏特点与含化石岩性的差别显示了不同层位有着不同的沉积环境。气候干湿、冷暖的交替不断改变着本区动植物的面貌。     

中国新近纪大型植食性哺乳动物演化和生物地层

中国新近纪大型植食性哺乳动物包括长鼻目、蹄兔目、奇蹄目、偶蹄目4个目至少32科,超过300种。它们在全球的演化和迁徙受到新近纪全球气候改变的驱动以及海陆分布的影响,各门类组成和地理分布由古近纪的古老面貌向第四纪的现代面貌转变。长鼻目和蹄兔目是非洲起源的类群;中国蹄兔目的种类和地史分布非常局限,但非常特化;中国的长鼻目则相当繁盛,成为长鼻类的第二演化中心和跨洲交流的十字路口。奇蹄目和偶蹄目是欧亚大陆起源的类群;相比古近纪,奇蹄类在新近纪持续衰落,但马科和犀科的多样性高,演化速率快,成为地层对比的标志性类群;偶蹄类则呈持续繁荣的状态,特别是反刍的优势使鹿科和牛科达到非常高的多样性,成为新近纪大型植食性哺乳动物中占优势的类群。中国新近纪大型植食性哺乳动物各门类中的现代类型均在山旺阶开始适应辐射,时间上对应于中中新气候适宜期,到通古尔阶中中新气候转型期开始多样性下降,在通古尔和灞河阶界线上发生了大型哺乳动物的灭绝和重组事件,90%的类群灭绝;至灞河阶下部,开阔生态系统成为中国北方的主导,产生了早期适应开阔环境的哺乳动物群,并逐渐扩散到全球;保德阶上部气候转湿润,诱发了南方哺乳动物群的北迁事件,...     

甘肃秦安崖湾剖面新近纪哺乳动物化石及其生态环境特征

甘肃东南部的天水盆地新近纪沉积十分发育,其中富含哺乳动物化石,自20世纪六、七十年代发现铲齿象等哺乳动物化石后,一直鲜有关于这一地区化石发现的报道.近几年,在对天水盆地北部秦安一带的新生代地层研究过程中,经过野外考察和测量,确认秦安县城西北部约15.5km郭嘉镇附近的崖湾剖面属于新近系沉积,其沉积地层大致可以划分为3段(共37层),并于第二段的23层(褐红色砂质泥岩层)和28层(褐红色粉砂质泥岩层)中发现了丰富的哺乳动物化石,经有关专家鉴定属于三趾马动物群,共包含有5目10科11属13种.其中上化石层(第28层)三趾马动物群主要代表性属种有Hipparion chiai,H.weihoense,H.fossatum,H.plocodus,Acerorhinusfuguensis,Chilotherium wimani,Ch.habereri,Chleuastochoerus stehlini,Palaeotragus microdon等,其化石组合时代大致与府谷喇嘛沟动物群和临夏盆地大深沟动物群相当,时代可能为保德期早期,相当于欧洲MN11.下化石层(第23层)哺乳类可能为晚中新世灞河期晚期,相当于欧洲MN10.由于本地区正好位于我国东部季风区向青藏高原区的过渡区,因此,崖湾剖面上化石层动物群代表了晚中新世华北三趾马动物群与青藏高原三趾马动物群之间过渡区域的三趾马动物群面貌,其化石组合特征反映出当时该区可能属于亚热带稀树草原的生态环境特征,气候相对较为适宜,是比较适合大型哺乳动物生存的.该区具有过渡性质三趾马动物群的发现,对于研究三趾马动物群在我国境内的分异与东西演化、确定该区地层年代以及古生态环境都具有重要的意义.     

西藏札达盆地腹足类组合及生物地层学

在西藏札达盆地古格组第四岩性段发现大量腹足类化石:Adelinella regularis Yü(规则小隐螺)、Velutinopsis spiralis Yü(旋纹似天鹅绒螺)、Radix zandaensis sp.nov.(札达萝卜螺)、Hip peutis cf.minor(Ping)(微小圆扁卷螺),称为小隐螺-似天鹅绒螺组合。根据这些腹足类化石在西藏西南部的分布特征,认为它们是分布于北喜马拉雅山间断陷盆地的一个腹足类组合,介于西藏犀类化石与杜氏珠蚌-河北珠蚌层之间,时代处于晚上新世-早更新世之间。对比现生种属研究认为,札达盆地腹足类应生活于近岸的浅湖环境。孢粉分析认为化石层形成时为温暖潮湿的森林-草原环境,化石层下部的三趾马生活在温暖而显干旱的灌丛草原环境,可知札达盆地由托林组至古格组,古气候经历了由温暖干旱向温暖潮湿的转变过程。     

青海西宁盆地三趾马、副板齿犀化石的发现及意义

首次在青海西宁盆地新近纪河湖相沉积地层中发现了三趾马、副板齿犀牙齿化石,对化石的基本特征和埋藏情况进行了描述,三趾马化石经鉴定为东乡三趾马。结合区域和前人资料认为,本次发现化石的岩石地层应该属于咸水河组或以上层位,时代为晚中新世早期。分析前人孢粉资料认为化石形成时的古植被为森林-草原,古气候环境为亚热带干旱气候环境。这一发现为西宁盆地晚新生代河湖相地层格架的建立,提供了古生物学依据,对西宁盆地中新世地层确立起到时序标尺的作用。为青藏高原东北缘盆地的环境演化、地层划分、时代厘定提供了新的资料,对深入研究青藏高原隆升环境效具有重要意义。同时,也为青藏高原东北缘、华北地区、青藏高原三趾马动物群进行对比研究,提供了基础材料。     

甘肃西峰6.2～2.4MaB.P.红粘土中孢粉记录及古植被演化

通过对甘肃西峰赵家川6.2～2.4MaB.P.红粘土地层的孢粉学研究,建立了3个孢粉组合带。孢粉组合特征显示该区在此阶段总体为干旱的草原环境,6.2～5.8MaB.P.为灌丛草原;5.8～4.2MaB.P.是稀疏森林草原,植被由大量中生性草本植物和少量喜湿性的乔木植物组成,反映当时气候相对湿润;4.2～2.4MaB.P.植被中旱生植物藜科和麻黄明显增多,反映典型草原-荒漠草原。分析认为研究区自6.2MaB.P.干旱草原环境的格局就已经形成。红粘土中孢粉记录的植被演化信息与青藏高原隆升有时代上的耦合性,也与北极冰盖的起源和演化历史有着密切的联系。     

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