准噶尔盆地吉木萨尔南部中上二叠统沉积古环境分析

准噶尔盆地东南缘吉木萨尔南部中上二叠统发育的泥页岩厚度大、分布广泛、有机质含量高,含有丰富的油气资源。通过对准噶尔盆地东南缘吉木萨尔南部中二叠统芦草沟组和上二叠统梧桐沟组进行了系统的采样,对泥页岩样品开展了生物标志化合物和元素地球化学分析,研究了该区中二叠统芦草沟组和上二叠统梧桐沟组泥页岩沉积时的氧化还原条件、古盐度和古气候特征。结果表明：①中二叠统芦草沟组沉积期处于贫氧的弱还原环境,有机质来源整体上以低等水生生物、沉水植物、原核生物等为主,芦草沟组中段混有少量高等植物输入;上二叠统梧桐沟组沉积期处于弱氧化—弱还原的环境,有机质来源整体上以低等水生生物、沉水植物、原核生物等为主,可能混有少量的高等植物,与芦草沟组相比有较多的沉水植物、泥炭藓、原核生物等;②中二叠统芦草沟组沉积时期湖盆为咸化—半咸化的水体,以干热的古气候条件为主;而上二叠统梧桐沟组沉积时期则为弱咸化—淡水的湖盆水体环境,以温暖湿润的古气候条件为主;③中二叠世至晚二叠世,研究区湖盆水体整体上呈现咸化程度降低,沉积有机质来源以低等水生生物、沉水植物、原核生物等为主,古气候呈由干热变为温暖湿润的演化趋势。     

渤海湾盆地渤中凹陷西南部沙三段富有机质泥岩沉积环境及形成机理

有机质富集受多种因素影响,分析富有机质泥岩发育的控制因素对于页岩油气资源的勘探开发具有重要意义。通过对渤海湾盆地渤中凹陷西南部沙河街组三段（沙三段）中—下亚段（Es₃^m-l）泥岩岩心样品进行总有机碳含量（TOC）以及主量、微量元素地球化学分析,讨论Es₃^m-l沉积期古气候、沉积水体环境、沉积速率及古生产力对有机质富集的影响,建立Es₃^m-l有机质富集模式。结果表明：Es₃^m-l泥岩有机质丰度较高,TOC含量介于1.05%~6.37%之间;CIA_corr反映整体为温暖湿润的古气候,Es₃^l下部相对干旱,Es₃^l中上部到Es₃^m气候变得更加温暖湿润;B含量和B/Ga值反映整体盐度较低,为淡水—半咸水,Es₃^l中上部到Es₃^m水体盐度变大;Mo-U协变模式和C_org/P摩尔比反映Es₃^m-l底水保存条件存在波动,整体为弱氧化—还原环境;Ti/Al、K/Al、Zr/Al表明Es₃^m-l沉积期陆源碎屑输入较强,具有较高的沉积速率,Es₃^l下部到Es₃^m沉积速率降低;古生产力定量恢复表明Es₃^m-l沉积期湖泊古生产力整体较高。渤中凹陷西南部Es₃^m-l泥岩有机质的富集是古气候、保存条件、沉积速率及古生产力共同作用的结果。     

土壤胶膜的研究进展

土壤胶膜是土壤中普遍存在的形成物,其性质与整个土体有较大的变异和不同,对土壤的物质流和能量流、生产力和植物营养以及土壤质量等有重要影响。本文从土壤胶膜的成因、分类、微形态特征、物质组成及其对土壤性质的影响,土壤胶膜与土壤发生与分类、古气候等的关系,探讨了土壤胶膜的研究进展,并展望了以后可能的研究趋势。     

吐哈盆地台北凹陷早侏罗世孢粉组合

吐哈盆地台北凹陷早侏罗世地层中产孢粉化石共85属104种,根据孢粉化石在纵向上典型属种的分布及优势组分含量变化规律,可化分为两个孢粉组合：Deltoidospora—Osmundacidites—Pinuspollenite组合,Leiotrites—Pinuspollenites—Quadraeculina孢粉组合,它们分别产自八道湾组和三工河组。根据孢粉组合特征和国内外相关资料对比,八道湾组的时代应属早侏罗世早期,三工河组的时代应为早侏罗世晚期。     

碳酸盐岩中稳定同位素对古气候的表征

碳酸盐岩中稳定同位素组成对古气候和古环境具有较为明显的表征意义。根据对广泛分布于塔里木盆地的下古生界碳酸盐岩的碳、氧稳定同位素分析,绘出了浅水台地相的柯坪剖面和深水盆地相的库鲁克塔格剖面寒武系底部至奥陶系顶部稳定同位素地层曲线。经过两地的对比并结合稳定碳、氧同位素组成特点,认为：在塔里木地区,晚震旦纪晚期至寒武纪早期有陆地冰川发育,海水温度较低,利于有机质的保存,应为烃源岩发育期,台地相碳酸盐岩与盆地相页岩均可成为良好的烃源岩;早寒武世晚期至早奥陶世,浅水台地区有机质埋藏率下降,但深水区有机质的埋藏率增加;中、晚奥陶世是又一个烃源岩广泛发育期。图３ 参７（王大锐摘）     

渤海湾盆地歧口凹陷沙河街组烃源岩沉积环境及形成机理

烃源岩分布与其形成环境密切相关,对油气分布具有重要影响。对烃源岩的评价及其形成环境的研究可为渤海湾盆地黄骅坳陷歧口凹陷下一步的勘探指明方向。从烃源岩发育特征和演化过程入手,深入研究了歧口凹陷沙河街组烃源岩的地球化学特征、分布规律及形成机理。结果表明：沙河街组烃源岩有机质丰度达到了中等—最好的级别,有机碳含量整体呈现从沙三段（Es₃）到沙一下亚段（Es₁^x）到沙一上亚段（Es₁^s）先增大后减小的特征;有机质类型为I型—III型,且沙一上亚段、沙一中亚段以I型—II₁型有机质为主,沙一下亚段、沙二段（Es₂）、沙三段I型—III型有机质均有分布,反映沙河街组沉积期有机质来源为湖泊原生有机质和陆源有机质混源。沙河街组烃源岩在平面上的分布具有分布范围广、沉积厚度大的特征,优质烃源岩在斜坡区更为发育。古气候研究结果表明,在沙河街组沉积期,该地区风化强度中等,整体以温暖湿润的古气候条件为主,有利于生物的发育。歧口凹陷沙河街组沉积期水体古盐度较大,属于半咸水环境。古盐度与古气候之间没有明显的相关关系,水体咸化的原因可能与海水入侵有关。古盐度和有机质含量的关系表明：在低盐度阶段,有机质含量随古盐度的升高而增大;在高盐度阶段,有机质含量随古盐度的升高而减小。根据微量元素比值和C_org∶P摩尔比值,歧口凹陷沙河街组沉积期发育氧化—亚氧化的沉积环境,Pr/Ph值显示在Es₁^x间歇性发育强还原环境,提高了有机质的保存条件。通过对沙河街组沉积期湖泊古生产力的恢复,沙河街组沉积期歧口凹陷整体上为中—富营养湖泊,板桥地区古生产力较低,为贫—中营养湖泊。歧口凹陷整体相对较高的古生产力水平及较高的陆源有机质输入量为该地区有效烃源岩的形成提供了物质基础。在纵向上,沙河街组沉积期古生产力水平具有Es₁>Es₃>Es₂的特征。古生产力条件是影响歧口凹陷沙河街组烃源岩形成的主要因素。由于斜坡区陆源有机质和水生有机质的双重贡献,优质烃源岩更为发育。     

吐哈盆地托克逊地区二叠系—侏罗系分布概况及古生态古气候初探

通过对吐哈盆地托克逊地区二叠系、三叠系、侏罗系的野外剖面实地观察及大量化石鉴定成果的综合分析,认为该区地层发育不全,侏罗系源岩的区域性盖层齐古组(Ｊ3ｑ)缺失,局部性盖层残缺不全。该地区的主力源岩应以上二叠统和三叠系为主。同时通过对中生代淡水瓣鳃类、脊椎动物的研究,对该区晚三叠世—侏罗纪古生态环境及古气候变迁进行了初步探讨     

Discovery and significance of Quaternary aqueously deposited aeolian sandstones in the Sanhu area, Qaidam Basin, China

Influenced by neo-tectonic movement, the Sanhu area of China’s Qaidam Basin formed in the Quaternary in response to migration of its depocentre. A study of core material from the Qijia 1 Well reveals novel Quaternary aqueously deposited aeolian sandstones in the Qigequan Formation of the Sanhu area. Here we report the sedimentary petrology and geochemistry data of these deposits that constrain their depositional history. Evidence for aeolian influence during deposition includes: sorting and roundness, pure quartz sand with single mode grain size distribution and few suspension materials, very fine sand grain size distribution indicating sorting by saltation and suspension transport, dish-shaped and crescentshaped pits in grain surfaces indicating aeolian transport and chemical composition similar to that observed in active or recent dune deposits, namely enrichment in SiO₂, Na₂O, and MgO relative to the sand dam sediment in the lakeshore. Identification of these aqueously deposited aeolian sandstones expands the range of sedimentary deposit types found in the Sanhu area and improves understanding of its paleoclimatic history.     

A review of the New Geophysics: a new understanding of pre-fracturing deformation in the crack-critical crust with implications for hydrocarbon production

This paper reviews a new understanding of shear-wave splitting （seismic-birefringence） that is a fundamental revision of conventional fluid-rock deformation. It is a New Geophysics with implications for almost all solid-earth geosciences, including hydrocarbon exploration and production, and earthquake forecasting. Widespread observations of shear-wave splitting show that deformation in in situ rocks is controlled by stress-aligned fluid-saturated grain-boundary cracks and preferentially orientated pores and pore-throats pervasive in almost all igneous, metamorphic, and sedimentary rocks in the Earth＇s crust. These fluid-saturated microcracks are the most compliant elements of the rock-mass and control rock deformation. The degree of splitting shows that the microcracks in almost all rocks are so closely spaced that they verge on fracture-criticality and failure by fracturing, and are critical systems with the “butterfly wing＇s” sensitivity of all critical systems. As a result of this crack-criticality, evolution of fluid-saturated stress-aligned microcracked rock under changing conditions can be modelled with anisotropic poroelasticity （APE）. Consequently, low-level deformation can be： monitored with shear-wave splitting; future behaviour calculated with APE; future behaviour predicted with APE, if the change in conditions can be quantified; and in principle, future behaviour controlled by feed-back. This paper reviews our current understanding of the New Geophysics of low-level pre-fracturing deformation.     

The Chang 7 member of the upper Triassic in the southwest Ordos Basin： Carbon isotope studay of dispersed organic matter and its paleoclimate significance

The Taoudeni Basin is a typical steady intracratonic basin. Based on the distribution of effective source rocks in the Taoudeni Basin, combined with the structure characteristics of the basin and the distribution characteristics of reservoir beds, two petroleum systems are recognized in the basin： the infra-Cambrian petroleum system and the Silurian petroleum system. Structural uplift and timing of petroleum generation controlled the timing of petroleum charging and preservation of hydrocarbon accumulations. Maturity, evolution history, and distribution of effective source rocks controlled hydrocarbon richness. The geological key factors and geological processes controlled the type of hydrocarbon accumulations.