川东地区石炭系碳酸盐岩碳、氧、锶同位素特征及其成因分析

利用微量元素和碳、氧同位素特征对样品有效性作出了检验.在证明样品未受明显蚀变的前提下对川东地区石炭系碳酸盐岩碳、氧、锶同位素进行了分析.在层序地层格架中对比不同体系域、不同岩性的碳、氧同位素特征,87Sr/86Sr比值特征,Z值与古温度特征,分析了碳酸盐岩的成岩环境.低位体系域以膏盐湖及萨巴哈环境为主,炎热干旱,陆源淡...     

海相烃源岩的正反演对比分析

海相优质烃源岩有效的评价体系是海相地层油气勘探开发中的关键问题之一.沉积盆地内保存的残余有机质从生物物质到烃源岩的演化过程经历了两个阶段, 即从生物物质到沉积有机质的形成阶段和从沉积有机质到残余有机质的烃源岩形成阶段, 后者包括沉积有机质在未熟阶段经历生物化学作用成为埋藏有机质和在成熟-过成熟阶段经历热解作用成为残余或风化残余有机质两个亚阶段.烃源岩反演分析是利用残余或风化残余有机质的量来推断埋藏有机质的量或者原始生烃潜力.而正演分析则是根据沉积物沉积环境、生物物质及其介质物理化学条件特征运用地球生态学、地球微生物学、分子地球生物学和生物地球化学方法推断沉积有机质的量, 甚至推断埋藏有机质的量, 进而评估烃源岩的原始生烃潜力, 也就是利用生物生产力和保存环境等综合分析沉积有机质的量.正反演对比分析相互验证和相互补充, 更好地揭示了烃源岩基本特征, 为海相优质烃源岩的预测和评价提供了有效的研究方法.      

四川盆地下奥陶统桐梓组白云岩多元成因

四川盆地下奥陶统桐梓组白云岩的成因研究较少,模式存在多样性,尚未达成共识.通过系统的岩心观察、薄片鉴定、地球化学分析等方法,在四川盆地桐梓组识别出晶粒白云岩、颗粒白云岩和含石英白云岩及含白云质石英砂岩等与白云石相关的岩石类型.地球化学分析揭示不同类型白云岩具有不同的地球化学特征及白云石化机理,晶粒白云岩的MgO含量与C...     

How Burial Time of Avalanche Victims is Influenced by Rescue Method: An Analysis of Search Reports from the Alps

Two hundred and seventeen avalanche reports from Switzerland and the Tyrol were used to investigate the influence of rescue method on the survival and burial time of avalanche victims. The probability of survival for victims rescued by their companion was higher (75, n=113) than for people found by an organised search team (30, n=104). Burial time and burial depth are the main factors, which decide whether a person is recovered dead or alive. People who were still alive were recovered significantly earlier and from a shallower burial depth than people who died in an avalanche. There is also a significant difference in the burial time dependent on whether companions or rescue teams carry out the search. In localising the site by means of sight/call or avalanche beacon by companions there is a clear relation between burial time and burial depth. For rescue teams, the relation between burial time and area of the avalanche is important. When working with avalanche dogs or probe lines there should be a clear correlation between burial time and area of the avalanche For dog teams arriving at the scene, there is a relation between search/excavation time and burial depth. Search time for tour skiers based on the information given will always be limited due to the burial depth of the victim. This means that the digging tools used are very important. The greatest problems facing rescue teams are limited transport capacity and the organisation of the whole mission over a large area. Therefore, speed and efficiency are of the utmost importance, when organising any search.     

埕岛油田海底天然气管道掩埋状况勘测及其影响因素分析

以胜利埕岛油田海底长输天然气管道为例，较系统介绍了海底管道勘测方法，根据调查资料成果，划分了调查地区地貌特征类型，给出了天然气埋设探测状况，总结了水深变化规律和区域水深差异特点，分析了水深变化、海底冲蚀和地质作用等因素对海底管道可能造成的影响，为管道安全生产、灾害预报评估和今后海上工程调查研究提供参考。     

划分成岩作用与埋藏变质作用的指标及其界线

本文是对“陕北鄂尔多斯盆地埋藏变质作用研究”一文的讨论,它综述并讨论了划分成岩作用和埋藏变质作用的指标,界线及其在鄂尔多斯盆地中的应用。伊利石结晶度、粘土矿物、浊沸石胶结物,石油形成,镜质体反射率,煤阶和地温等指标一致表明,鄂尔多斯盆地中生代地层处于中期成岩作用阶段,从而否定了本区为埋藏变质地区的结论。     

陆地原位宇宙成因核素(TCN)在地表过程与构造活动关系研究中的应用

大地构造、气候变化和地表过程间的耦合作用被视为今后10年内六大地学新课题之一，而从事这一重大课题研究的有效途经便是陆地原位宇宙成因核素的研究和应用。从目前该领域的研究实践来看，经常使用的是^3He、^10Be、^14C、^21Ne、^26Al和^36Cl核素，其中石英的^26Al和^10Be的配合使用最为普遍。通过陆地原位宇宙成因核素（TCN）方法基本原理的阐释，并结合当今国际上该领域利用^10Be和^26Al在暴露年龄与侵蚀速率、沉积物埋藏年龄以及河流下切速率等方面的工作实例．介绍陆地原位宇宙成因核素在地表过程以及地表过程与构造活动相互关系研究上的应用。     

Burial dolomitization driven by modified seawater and basal aquifer‐sourced brines: Insights from the Middle and Upper Devonian of the Western Canadian Sedimentary Basin

Dolomitization in the Western Canadian Sedimentary Basin has been extensively researched, producing vast geochemical datasets. This provides a unique opportunity to assess the regional sources and flux of dolomitizing fluids on a larger scale than previous studies. A meta‐analysis was conducted on stable isotope, strontium isotope (⁸⁷Sr/⁸⁶Sr), fluid inclusion and lithium‐rich formation water data published over 30 years, with new petrographic, X‐ray diffraction, stable isotope and rare‐earth element (REE+Y) data. The Middle to Upper Devonian Swan Hills Formation, Leduc Formation and Wabamun Group contain replacement dolomite (RD) cross‐cut by stylolites, suggesting replacement dolomitization occurred during shallow burial. Stable isotope, REE+Y and ⁸⁷Sr/⁸⁶Sr data indicate RD formed from Devonian seawater, then recrystallized during burial. Apart from the Wabamun Group of the Peace River Arch (PRA), saddle dolomite cement (SDC) is more δ¹⁸O_(PDB) depleted than RD, and cross‐cuts stylolites, suggesting precipitation during deep burial. SDC ⁸⁷Sr/⁸⁶Sr data indicate contributions from ⁸⁷Sr‐rich basinal brines in the West Shale Basin (WSB) and PRA, and authigenic quartz/albite suggests basinal brines interacted with underlying clastic aquifers before ascending faults into carbonate strata. The absence of quartz/albite within dolomites of the East Shale Basin (ESB) suggests dolomitizing fluids only interacted with carbonate strata. We conclude that replacement dolomitization resulted from connate Devonian seawater circulating through aquifers and faults during shallow burial. SDC precipitated during deep burial from basinal brines sourced from basal carbonates (ESB) and clastic aquifers (WSB, PRA). Lithium‐rich formation waters suggest basinal brines originated as residual evapo‐concentrated Middle Devonian seawater that interacted with basal aquifers and ascended faults during the Antler and Laramide Orogenies. These results corroborate those of previous studies but are verified by new integrated analysis of multiple datasets. New insights emphasize the importance of basal aquifers and residual evapo‐concentrated seawater in dolomitization, which is potentially applicable to other regionally dolomitized basins.     

西沙群岛西琛1井碳酸盐岩白云石化特征及成因机制

西沙群岛西琛1井碳酸盐岩地层可分为3个白云岩层和4个石灰岩层。白云岩层白云石矿物体积分数为91.1%~100%,其他矿物小于8.9%,以泥晶为主,分布在岩石的骨架颗粒和孔隙充填物等各种结构组分中。白云岩δ13C为0.80‰~3.16‰,平均为2.24‰;1δ8O为0.56‰~5.23‰,平均为2.56‰。这些特征反映了白云石化作用发生在准同生超浓缩卤水条件下,古盐度为36.88%,古温度为1.07℃。石灰岩层白云石矿物体积分数多在25%以下,以亮晶为主,在孔隙或裂缝发育部位富集,而坚硬的骨架部位几乎没有白云石。白云石流体包体的均一温度为102.5~296℃,平均为156.3℃;盐度为0.55%~6.25%,平均为3.75%;密度为0.95~0.99 g/cm3,平均为0.97 g/cm3;压力为20.65~42.65 MPa,平均为33.65 MPa。这些特征反映了白云石化作用可能与成岩期后热水作用相关。     

准噶尔盆地莫西庄地区下侏罗统储层性质

准噶尔盆地莫西庄地区侏罗系储层具有低成分成熟度、富含岩屑、低杂基含量和高结构成熟度的岩石学特征。孔隙类型主要有残余粒间孔、溶扩粒间孔、粒内溶孔、晶间孔和微裂隙等,其中又以前两种为主,含量分别为25%和56%。通过对压汞测试结果和铸体薄片的物性资料统计分析,笔者认为莫西庄地区砂岩储集性能主要受沉积物粒度、沉积相类型、成岩作用及埋藏条件的控制。其中,埋藏条件是本区保持好储集性能的基础,成岩作用对储集性能起着直接的控制作用,沉积物粒度和沉积相类型对储层的影响是首要的。资料分析均表明,三工河组二段下亚段是本区的优质储层层段,八道湾组储集性能相较较差。