不同水动力下陆相碳酸钙沉积的蓝藻钙化试验的初步研究

 地表钙华,是喀斯特地区普遍存在的一种沉积体,是陆相碳酸钙沉积的重要类型。长期以来陆相碳酸钙沉积的水动力成因观点为大多数人所熟悉(1)（2）,生物成因观点则研究较少,在实际中生物作用过程也是不可忽略的,特别是藻类的沉积作用。论文以几种典型的蓝藻为例,通过对自然界水动力条件的模拟,对蓝藻藻类进行了几种水动力条件下的碳酸钙生物沉积试验研究,对比研究了在不同水动力条件下,蓝藻钙化沉积过程。试验得出了钙藻生长与钙化沉积的最适宜水动力为0~60 rpm,在过强的水动力条件下,蓝藻的生长将受到抑制,从而降低蓝藻的钙化沉积速率。文章讨论了在瀑布条件下的陆相碳酸钙沉积是以水动力成因为主导,而在水动力条件较弱的河流中以生物成因为主导,从而提出了,陆相碳酸钙沉积的水动力-生物双成因观点。文章还探讨了在静止状态下,藻类沉积对碳酸钙沉积的贡献大小,叠层石所指示的安静的沉积环境。      

广西北海现代海岸沉积作用

本文讨论了广西北海现代海岸各种环境的自然地理分带、地质营力、沉积物以及生物生态等特征，指出环境能量直接决定了环境类型、沉积物类型以及生物组合类型。海岸环境据其能量划分为高能海滩、低能海湾、中能岩质潮坪和砂质潮坪、低能泥质红树林潮坪以及高能潮上沙丘等6种沉积类型；混合沉积作用主要发育于高能海滩和中能潮坪沉积环境内。涠洲岛现代地壳的上升活动控制着该区海蚀地貌的形成。     

陆相断陷盆地陆源碎屑与碳酸盐混合沉积研究进展

陆源碎屑与碳酸盐（岩）混合沉积现象普遍发育并已成为有利的油气勘探类型,但陆相断陷盆地混合沉积类型多样、成因复杂,是当今沉积地质学的研究热点和难点.基于渤海油田大量勘探实践及国内外研究成果的调研,归纳总结了陆相断陷盆地混合沉积研究所取得的主要进展,提出了目前混合沉积研究面临的主要问题.陆相混合沉积研究历程可划分为起步阶段、快速发展阶段和综合研究阶段.由于地质条件的差异性,混合沉积岩性鉴定方案并未形成统一的标准.陆相断陷盆地混合沉积具有复杂的成因类型,包括近源混合沉积、远源混合沉积2大类及6种具体沉积类型.渤海油田首次建立了独立的陆相断陷盆地混合沉积相体系.陆相混合沉积形成的主控因素包括稳定的宏观构造背景与局部强断裂活动、盆内局部凸起碎屑供给的不稳定性、相对干旱的气候与较高盐度的水体条件、正向的古地貌背景.近源扇三角洲混合型、近源扇三角洲侧翼型、近源辫状河三角洲侧翼型、远源高能粗粒型混合沉积优质储层是目前较为有利的混合沉积勘探类型.古地理条件约束、地质模式主导是有效的混积型储层预测思路.现阶段陆相混合沉积研究中需要重视的关键性问题主要包括以下几个方面:混合沉积岩性分类方案,钙质壳体生物发育规律及微生物白云岩化作用,细粒混合沉积与页岩油气储层的关系,混积型储层地球物理预测技术.      

洞穴碳酸钙沉积的水运条件

<正> 洞穴碳酸钙是洞穴中分布最广的一种洞穴矿物沉积,它在洞穴内的堆积形成了千姿百态的洞穴碳酸钙沉积形态,国内外的洞穴科学工作者对其沉淀机制、速度和形态成因等诸方而做了大量的工作。然而,对这些工作结果的认识还存在着不少分歧。作者认为,洞穴碳酸钙的形成是借助于水这个媒介物质,水运动条件的变化,首先对沉淀的物理化学条件产生重大影响,使沉淀的情况有所改变;其次,按照水运动条件等因素划分的洞穴水类型与洞穴碳酸钙形态形成密切相关。同时,由于沉淀和溶解是互逆反应,碳酸钙沉淀理论的解决将导致喀斯特溶蚀理论的完善。      

唐山滨海湿地表层沉积物类型及环境示踪

沉积物是环境生态系统中重金属污染程度的重要指示剂。其微观上可以为重金属在沉积物中的化学组成及其与环境的关系等方面的机理提供重要的证据;宏观上则是对环境质量现状、污染程度进行正确评价的前提。在前人研究的基础上,对渤海湾唐山滨海湿地表层沉积物基本理化性质及重金属含量、粒度参数的分析,运用Sr/Ba值和沉积物中Sr、Ga、V含量对陆相和海相沉积进行示踪;运用Cu/Zn值,来示踪当时氧化-还原情况;用Sr/Cu比值法,对当时的气候进行恢复。讨论了唐山滨海湿地表层沉积物的主要类型,该沉积相大多数为滨浅海沉积和三角洲沉积,主要为氧化状态,水动力条件处在中高能。     

滇西地区陆相热水沉积成矿作用

本文通过对云南西部兰坪铅锌矿床、金满铜矿床、勐野井钾盐矿床和腾冲松木箐金矿床的地质地球化学研究,认为它们是在陆相条件下热水沉积形成的。根据矿床的产出特征,把陆相热水沉积的矿床划分为3种类型:泉华沉积型;盆地沉积型;脉状沉积型。本文还对热水沉积矿床与现代海底热水(喷流)矿床进行了对和提出了陆相热水沉积的成矿模式,最后对我国陆相热水沉积矿床的找矿方向提出了粗浅的建议。     

陆相碳酸钙沉积试验的晶体扫描电镜研究

通过室内及野外沉积试验,并结合扫描电镜照片,研究了不同温度下静水环境及动水环境中,碳酸钙晶体生长速度及发育特征。研究发现: 在静水环境条件下碳酸钙结晶过程为在水面最先形成钙膜,然后向水深处,碳酸钙晶粒依次析出。文章中还证实了在掺气的水体中碳酸钙晶体可以迅速生长。在水补给条件较差及有蒸发作用参与时,则形成碳酸钙晶体花,或针状碳酸钙。此外,文章对流水作用下碳酸钙晶体的侵蚀特征也给予了初步的讨论。      

珠江口盆地惠州凹陷南部珠江组混合沉积作用

珠江口盆地惠州凹陷南部珠江组下部广泛发育陆源碎屑岩与碳酸盐岩的混合沉积。通过测井、地震和岩心等资料综合研究了工区混合沉积的岩石学特征、沉积模式和分布规律。研究认为工区混合沉积可分为相缘混合和原地混合,相缘混合主要是在浅海三角洲相和碳酸盐岩台地相边界的结合部位、在低能水动力环境下的细粒陆源碎屑与泥晶碳酸盐的混合沉积,原地混合主要是在三角洲前缘高能水动力条件下的砂级硅质碎屑颗粒与碳酸盐生物碎屑的混合沉积。原地混合沉积对储层的储集性能和渗流特征有显著影响。描述了原地混合沉积的泥岩—碳酸盐岩—砂岩—碳酸盐岩—泥岩相层序,并讨论了陆源碎屑注入、古地形、海平面升降及三角洲迁移等影响透光带范围的因素是如何控制研究区的混合沉积分布的。     

白垩纪特殊沉积的古气候指示及红层定量古温度测量研究

介绍了白垩纪陆相红层研究的现状及前景,特别是其在白垩纪陆相古气候恢复方面所具有的重要意义。系统讨论了白垩纪陆相红层中的特殊沉积及其古气候指示意义,并讨论了碳酸盐岩氧同位素方法定量古温度恢复的可能性及其局限性。指出白垩纪古气候具有时间上和空间上的不均匀性;并结合陆相红层的类型、特殊沉积的分布,参照古生物的地理分区对白垩纪古气候进行初步地理分区。     

陆相伸展盆地的层序类型、结构和序列与充填模式--以冀中坳陷下第三系为例

陆相层序受自然地理景观、影响地层发育的地质营力及地层类型等因素影响,因此层序类型多种多样。在冀中坳陷同伸展期发育洪积层序、湖泊层序和冲积层序等三种层序类型。洪积层序是盆地伸展初期地貌反差较大物源供给充分气候干旱条件下发育的一种陆相层序类型,以冲积扇沉积为主,山高盆窄,汇水湖泊面积较小;湖泊层序发育在盆地强烈伸展基底快速沉降气候湿润湖泊水域宽深时期,湖泊水域宽,连通好,湖水深,是烃源岩发育的黄金时期。湖泊层序以湖泊沉积为主,其次为河流和少许冲积扇沉积。冲积层序是在盆地伸展末期地貌反差强度减弱物源距离逐渐加大时的沉积产物,主要为干旱气候条件下的河流、三角洲沉积,湖泊沉积局限。研究表明,影响陆相层序形成的构造、物源、气候等因素与湖泊水体或水平面变化构成一种多元“函数”关系,湖平面变化是上述因素的综合体现。陆相断陷盆地的层序结构大多与湖泊水体之间存在密切联系,因此层序的结构以三分为主。受地壳构造运动控制,断陷盆地发育的层序具有序列性,即下部洪积层序、中部湖泊层序和上部冲积层序。这种序列性是盆地充填对地壳幕式伸展的沉积响应。在盆地充填过程中,不同类型的陆相层序其体系域发育程度具有较大差异。一般地,洪积层序的低位域沉积?     

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.)