松辽盆地西部斜坡区四方台组砂岩中烃类流体特征与铀成矿关系

通过对松辽盆地西部斜坡区四方台组33个砂岩样品的酸解烃分析,探讨了酸解烃中烃类气体组成特征、成因及来源,并结合该地区铀矿化地质特征初步分析了烃类流体与砂岩型铀成矿关系.酸解烃中气体组成特征参数C₁/ΣC、C₁/C₂₊、C₂/iC₄、C₂/C₃、iC₄/nC₄、iC₅/nC₅特征表明,四方台组底部砂岩中烃类气体为有机成因的油气型,烃类气主要处于成熟-高成熟阶段,是原油裂解气和原油伴生的混合气,它们主要沿盖层断裂运移到四方台组底部砂岩中.西部斜坡区四方台组含铀砂岩中烃类流体含量普遍增高,表明该区四方台组铀矿化与烃类气体关系密切.四方台组底部靠近沟通油气田的盖层断裂附近是西部斜坡区砂岩型铀矿找矿的重点地区.     

天然气运移的气体组分的地球化学示踪

本文通过我国不同含油气盆地典型地区岩石酸解气、罐顶气和天然气中化学组分分析,结合天然气的形成和盆地的地质演化,研究了天然气运移时组分的变化。结果表明,天然气通过地层孔隙系统运移时,组分会发生明显分馏,表现在甲烷相对重烃、异构丁烷相对正构丁烷的优先迁移。酸解气、罐顶气和成藏天然气中C₁/C₂+、iC₄/nC₄及总烃/非烃等比值,是天然气运移示踪的有效指标。     

松辽盆地庆深气田天然气成因类型鉴别

通过对松辽盆地徐家围子烃源岩和原油热模拟实验、烷烃气碳同位素组成分析, 认为在高演化阶段单一热力作用可以引起重烃气(δ13C₂ > δ13C₃ > δ13C₄) 碳同位素组成倒转, 但CH₄与C₂H₆(δ13C₁ > δ13C₂) 却很难发生倒转.庆深气田天然气重甲烷碳同位素组成、烷烃气碳同位素完全倒转、高稀有气体同位素组成(R/Ra > 1.0), 说明该气田天然气来源具有多样性.利用R/Ra与CO₂/3He和R/Ra与CH₄/3He关系对庆深气田天然气成因类型进行识别, 认为该气田烷烃气中甲烷有部分为无机成因, 重烃气则为有机成因.该地区高地温梯度导致有机成因重烃气碳同位素组成发生倒转, 而CH₄与C₂H₆碳同位素组成倒转主要与重碳同位素的无机甲烷混入有关.      

天然气水合物形成过程中的气体组分分异及地质启示

自然地质条件下不同气源的天然气体由于其组成不同,对天然气水合物的成藏条件产生不同影响。以2个常规天然气样品为例,在中国石油大学自行研制的水合物成藏一维模拟实验装置上进行了水合物成藏模拟实验,并对实验前后的原始气样、水合物形成后的游离气、分解气进行了气体组分分析。实验结果表明：水合物分解气中CH₄、N₂含量降低,而C₂H₆、C₃H₈、iC₄H₁₀、nC₄H₁₀、CO₂含量增大,游离气中各组分的变化趋势刚好相反,这意味着同等的温度压力条件下,C₂H₆、C₃H₈、iC₄H₁₀、nC₄H₁₀、CO₂等与CH₄、N₂相比更易于形成水合物;通过计算分解气体各组分相对于原始气体的相对变化量发现,在实验温度压力条件下（高压釜温度范围为4~10 ℃,气体进口压力为5 MPa）,烃类气体与水结合形成水合物的能力由甲烷、乙烷、丙烷、异丁烷依次增加;由于不同烃类气体与水合物结合的条件不同,导致水合物形成过程中气体组分发生分异,水合物中甲烷含量减少、湿气含量增大,而游离气中气体变化相反,在自然地质条件下形成由水合物稳定带上部溶解气带、水合物稳定带及下部游离气带（或常规气藏）甲烷含量呈中-低-高特点,湿气和二氧化碳含量呈低-高-中的三层结构分布模式,因此,同一气源气体在不同带内表现出不同的气体组分特征。     

水驱对原油饱和烃馏分影响的分子地球化学表征

利用GC、GC/MS分析技术,对水驱开发的曲9油藏进行了原油饱和烃馏分的动态变化对比。研究表明,随着水驱推进,在9个多月的动态监测中,原油饱和烃馏份表现出明显的变化规律,逐渐升高的有饱和烃相对含量、C₁₅-RD/C₁₅-D、C₁₅8β（H）-D/C₁₆8β（H）-HD、TTs/17α-H、RS/17α-H等比值;逐渐降低的有芳烃相对含量、轻重比参数∑nC_21-/∑nC₂₂₊、∑nC_14-/∑nC₁₅₊;基本保持稳定不变的有异构烷烃比值Pr/Ph、iC₁₈/Pr、iC₁₈/Ph,萜烷比值C₂₁/C₂₂TT、C₂₄/C₂₃TT、∑C_19-26/∑C_28-29TTs、C₃₀*/C₂₉Ts、C₃₅R/C₃₄R、Ol/C₃₀H、G/C₃₁R、C₃₁22S/（22S+22R）、C₃₀M/C₃₀H、Ts/（Ts+Tm）、C₂₉Ts/（C₂₉Ts+C₂₉H）,甾烷比值C₂₇-DS/C₂₇-RS、C₂₉20S/（20S+20R）、C₂₉ββ/（ββ+αα）、C₂₇-重排甾烷20S/（20S+20R）等;先升高再降低,或先降低再升高的分异变化的有Pr/nC₁₇和Ph/nC₁₈。水洗作用造成芳烃相对含量与轻重比的降低,生物降解作用引起了三环萜烷与规则甾烷相对藿烷的富集,二者虽然对相近碳数的异构烷烃、萜烷、甾烷比值影响甚微,却合力促使了补身烷参数的升高。注水过程中的色层效应进一步导致了饱和烃馏分的分异。     

长江源区大气氮湿沉降时空变化特征

长江源区作为亚洲第一长河的发源地,探究其氮沉降特征,对于保护我国水源地安全具有十分重要的意义.本文在野外采样、数理分析的基础上,利用氮源分析及后向轨迹模型判断氮沉降的环境意义.结果表明:(1)2016年4月-2018年7月,NO₂^--N、NO₃^--N、NH₄⁺-N的平均浓度分别为1.01 mg/L、2.45 mg/L、1.30 mg/L;NO₂^--N、NO₃^--N、NH₄⁺-N的平均沉降量分别为0.02 kg/hm²、0.09 kg/hm²、0.30 kg/hm².曲麻莱氮浓度占源区比重最高,沱沱河次之,直门达最小,且春、夏季氮沉降量高于秋、冬季.(2)氮沉降浓度与降水量之间呈对数函数关系,沉降量与降水量之间呈正向幂函数关系;NO₂     

鄂尔多斯盆地苏里格庙与靖边天然气单体碳同位素特征及其成因

苏里格庙上古生界砂岩气藏天然气重烃含量高,干燥系数低,为湿气;靖边奥陶系风化壳气藏天然气重烃含量低,干燥系数高,属干气。苏里格庙天然气的正构烷烃碳同位素具有δ13 C₁<δ13 C₃ <δ13 C₂ <δ13 C4的规律,靖边天然气具有δ13 C₁<δ13 C₂ <δ13 C₃ 的规律。二者高碳数烷烃的同位素差别较大,尤其是苏里格庙的乙烷碳同位素比靖边平均重 3.6‰。根据天然气单体碳同位素及其含量变化,苏里格庙天然气属煤成气,靖边天然气属煤成气与油型气的混合气。苏里格庙和靖边天然气中均含少量CO₂ 气,其碳同位素表明苏里格庙除苏 5井为无机CO₂ 气外,均为有机CO₂ 气;靖边林 1、林 5井为无机CO₂ 气,陕参 1井为有机CO₂ 气。结合烷烃气和CO₂ 气,苏里格庙天然气可以分为含有机CO₂ 煤成气和含无机CO₂ 煤成气。碳同位素比值与Ro 关系分析认为,苏里格庙的天然气成熟度处于成熟到高成熟阶段,其相应气源岩的平均Ro 为 1.2 9%～ 1.39%,这一结果与该区二叠系煤岩的成熟度符合较好。     

松辽盆地滨北西部上二叠统林西组烃源岩生物标志化合物的特征及意义

应用气相色谱、气相色谱-质谱技术,研究了滨北西部上二叠统林西组烃源岩的生物标志化合物特征,对烃源岩有机质来源、沉积环境、热演化程度等进行了分析.研究表明,林西组烃源岩有机质丰度高,有机质类型为Ⅱ型,处于高成熟-过成熟演化阶段;烃源岩中（C₂₀+C₂₁）/（C₂₃+C₂₄）三环萜烷为0.12~0.86,平均为0.50,C₂₄四环萜烷/C₂₆三环萜烷为0.41~0.72,平均为0.54,具有典型湖相烃源岩特征;Pr/Ph主要介于0.16~0.71之间,平均为0.32,指示沉积环境为强还原-还原环境;伽马蜡烷/C₃₀藿烷为0.09~0.35,平均为0.21,反映烃源岩为半咸水的沉积环境;Pr/nC₁₇与Ph/nC₁₈的关系、C₂₇-C₂₈-C₂₉甾烷的相互关系均反映有机质为高等植物和细菌、藻类等低等水生生物的混合来源;Ts/Tm为0.18~1.03,平均为0.86,C₃₁αβ22S/（22S+22R）比值为0.53~0.62,平均为0.58,均指示烃源岩成熟度较高.综合认为林西组烃源岩形成于半咸水的还原-强还原环境,有机质来源为混合来源,有利于有机质的富集,林西组具有油气勘探前景.     

松辽盆地滨北西部上二叠统林西组烃源岩生物标志化合物的特征及意义

应用气相色谱、气相色谱-质谱技术，研究了滨北西部上二叠统林西组烃源岩的生物标志化合物特征，对烃源岩有机质来源、沉积环境、热演化程度等进行了分析.研究表明，林西组烃源岩有机质丰度高，有机质类型为Ⅱ型，处于高成熟-过成熟演化阶段；烃源岩中（C₂₀+C₂₁）/（C₂₃+C₂₄）三环萜烷为0.12~0.86，平均为0.50，C₂₄四环萜烷/C₂₆三环萜烷为0.41~0.72，平均为0.54，具有典型湖相烃源岩特征；Pr/Ph主要介于0.16~0.71之间，平均为0.32，指示沉积环境为强还原-还原环境；伽马蜡烷/C₃₀藿烷为0.09~0.35，平均为0.21，反映烃源岩为半咸水的沉积环境；Pr/nC₁₇与Ph/nC₁₈的关系、C₂₇-C₂₈-C₂₉甾烷的相互关系均反映有机质为高等植物和细菌、藻类等低等水生生物的混合来源；Ts/Tm为0.18~1.03，平均为0.86，C₃₁αβ22S/（22S+22R）比值为0.53~0.62，平均为0.58，均指示烃源岩成熟度较高.综合认为林西组烃源岩形成于半咸水的还原-强还原环境，有机质来源为混合来源，有利于有机质的富集，林西组具有油气勘探前景.     

辽宁北部秀水盆地秀D1井下白垩统义县组烃源岩生物标志化合物特征及意义

应用气相色谱、气相色谱-质谱技术,研究了秀水盆地秀D1井下白垩统义县组烃源岩的生物标志化合物特征,对烃源岩有机质来源、沉积环境、热演化程度等进行了分析.结果表明,秀水盆地秀D1井下白垩统义县组烃源岩有机质丰度高,有机质类型为Ⅱ型,处于成熟演化阶段;（C₂₀+C₂₁）/（C₂₃+C₂₄）三环萜烷为0.66~5.06,C₂₄四环萜烷/C₂₆三环萜烷为0.38~2.25,具有典型湖相烃源岩特征;烃源岩Pr/Ph主要介于0.5~1.0之间,指示还原环境;伽马蜡烷/C30藿烷比值为0.05~0.41之间,指示处于强还原性沉积环境,并且烃源岩沉积时水体的盐度较低以及可能存在水体盐度分层;Pr/nC₁₇、Ph/nC₁₈关系表明有机质类型主要为Ⅱ₁型,C₂₇-C₂₈-C₂₉甾烷的相互关系反映有机质来源应为低等水生生物和陆生高等植物的混合来源;Ts/Tm比值为0.45~1.82,C₃₁αβ22S/（22S+22R）比值为0.41~0.62,表明烃源岩处于低成熟-成熟演化阶段,并且具有义县组中、下部烃源岩成熟度较义县组上部高的特点.综合认为秀水盆地早白垩世义县组烃源岩形成于水体盐度较低的还原-强还原环境,有机质来源为混合来源,有利于有机质的富集,义县组具有较好的油气勘探前景.     

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.)