地层记录中的古气候信息及其与烃源岩发育的相关性——以渤海黄河口凹陷古近系为例

近年来的研究表明,凹陷中优质烃源岩的形成决定于有利的古气候和古湖盆环境,并受控于断陷期快速沉降的构造背景。着重论述了古气候条件对烃源岩发育的控制作用。根据渤海海域黄河口凹陷典型钻井样品中的孢粉、藻类等古生物资料,并结合岩相特征,对该地区古近纪各时期的古气候、古环境特征进行了恢复,本区古近纪共存在4个气候湿热、古湖盆水体发育的时期。另外通过与烃源岩发育特征的对比,发现各湿热的古气候时期均与优质烃源岩的发育情况有很好的对应关系,说明温暖、湿润的古气候条件对烃源岩的发育具有重要的控制作用。最后对气候影响烃源岩形成和保存的机理进行了分析。     

塔西南坳陷二叠系烃源岩控制因素探讨

为探讨塔西南坳陷二叠系烃源岩发育的控制因素,对烃源岩开展了微量元素和碳氧同位素分析研究。结果表明,该烃源岩受古盐度和古气候、原始生产力、氧化还原环境、海平面变化等因素综合作用的控制。其中,古盐度和古气候控制了烃源岩形成的沉积环境,原始生产力决定了有机质的富集和有机碳含量的高低,氧化还原环境决定了沉积有机质的保存情况,海平面变化对原始生产力和氧化还原条件等有重要的影响。这些因素综合作用控制了烃源岩的发育,同时又相互影响。     

海南岛西南部全新世海滩岩地球化学特征及其古气候意义

对海南岛西南部东方地区的潮间带海滩岩以及新发现的高排村埋藏海滩岩进行了微区稀土元素与碳、氧同位素分析,结果表明:高排村海滩岩亮晶胶结物ΣREE值以及LREE/HREE比值在几种不同类型胶结物中是最低的,但与文石、微晶高镁方解石等胶结物相比,其差值并不明显,说明陆地渗流环境对胶结物的REE影响有限。不同类型胶结物具有类似的配分特征,表现为轻稀土亏损,重稀土曲线平缓,具有铈负异常特征,并且与二叠纪海水和现代东太平洋海水配分模式基本一致。根据胶结物碳、氧同位素计算的出的古盐度Z均值为130,古海水平均温度为27℃,显示为热带海洋环境,与海南岛西南部气候吻合,指示海滩岩胶结物可作为记录古气候的良好载体。     

长岭断陷下白垩统湖相烃源岩形成古环境及主控因素

恢复烃源岩形成时期的古环境,落实优质烃源岩发育主控因素对确定湖相烃源岩发育层系及刻画烃源岩非均质性意义重大.利用岩石学、元素地球化学对长岭断陷早白垩世火石岭期至营城期的古环境进行恢复,并对反映古环境的微量元素含量及其比值与有机碳含量(Total Organic Carbon, TOC)进行相关性分析,确定控制湖相烃源岩发育的主要环境因素.研究表明,从火石岭期至沙河子期,再到营城期,长岭断陷经历了古水深从变深到变浅,古气候从潮湿-半潮湿气候到半干旱气候,古盐度从淡水相到半咸水相,湖泊水体还原性从增强到减弱的古环境演化过程,早白垩世不同时期长岭断陷古环境表现出明显的分带性,古气候和氧化还原条件是控制长岭断陷下白垩统湖相烃源岩发育的主要环境因素.长岭断陷沙河子组二段烃源岩形成于潮湿与缺氧的古环境,该时期湖盆演化处于均衡补偿阶段,且烃源岩古生产力较高,因此研究区沙河子组二段优质烃源岩十分发育,分布广.      

山东乳山海滩岩及其重要科学意义

乳山海滩岩,经过室内对微体化石、大化石和沉积岩石学研究,查明该岩体具有典型的海滩岩特征:含有两种文石胶结物、滨海相微体古生物和热带大化石。该岩体形成在全新世最佳气侯期,至少有3次成岩期,对研究古环境变化规律具有重要的科学意义。     

新疆吐哈盆地侏罗纪古植被与古气候及古环境的探讨

通过对新疆吐哈盆地侏罗系孢粉植物群、特殊岩性、泥质岩中的元素和粘土矿物分布规律的研究 ,探讨了古植被、古气候及古环境的纵向演化特点 ,认为研究区内侏罗纪古气候特点是早侏罗世至中侏罗世早期为温暖潮湿的亚热带 ,局部有干旱趋势 ;中侏罗世中晚期为半潮湿、半干旱的温带—亚热带气候 ;从中侏罗世末期开始转为炎热干旱的亚热带气候。     

珠江口盆地陆丰凹陷文昌组沉积地球化学特征及古环境意义

陆源营养物质输入是湖泊成油母质(细菌和藻类、浮游植物等)生长的主要外部营养源.古气候条件影响了陆源输入,湖盆水体沉积环境控制了有机质保存,因此沉积期古气候古水体条件对湖相烃源岩有机质丰度预测至关重要.针对珠江口盆地陆丰凹陷文昌组烃源岩进行环境地球化学研究,运用CIA、V/Cr、Mn/Al、Sr/Cu、Ti/Al等多种元...     

有机地球化学研究进展—在第四纪古气候古环境研究中的应用

有机地球化学研究进展──在第四纪古气候古环境研究中的应用耿安松（中国科学院广州地球化学研究所，广州５１０６４０）从沉积（无机）地球化学的角度研究第四纪古气候、古环境的变迁已经做了大量的工作，并取得许多成果。与之相比，从有机地球化学的角度研究第四纪古气...     

浙江鲻山遗址孢粉组合与先人活动的关系

文章通过对浙江鲻山遗址T8剖面进行孢粉组合分析，再结合孢粉－气候对应分析数理统计方法，得出了该遗址的古气候、古环境。对比河姆渡文化遗直，推断出鲻山文化遗址是其一个分支。     

柴达木盆地自然伽玛曲线在古气候及沉积环境研究中的应用

应用自然伽玛测井（GR）曲线反演古气候和古环境的方法在国际上逐渐得到重视并取得了进展，柴达木盆地第四纪应用其反演2.85Ma B.P来的古气候变化也取得了成功。本文以柴达木盆地侏罗系冷科1井和雨33井自然伽玛曲线并结合孢粉等地质资料进行了古气候与沉积环境分析，证明GR曲线是有价值的古气候研究参数。GR值的大小及古气候的干湿变化和沉积水体的深浅变化均有内在联系，GR曲线振幅与频率的变化快慢反映出沉积环境动荡与稳定的相对特征，据此对两口井的沉积环境演变作了具体分析。结合古气候与沉积环境综合分析，GR曲线的异常波动还具有特殊的指相意义。GR值增大-古气候加湿-沉积水体加深的同步表现特征是一般性规律，构造-古地理背景的变动可改变这一对应关系，因而提供了研究古地理演变的信息，进一步丰富了GR曲线研究的地质涵义。说明在侏罗纪古气候和古环境研究上，GR曲线是一有价值的参考指标。     

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.)