黔北下寒武统黑色岩系的沉积环境与地球化学响应

下寒武统黑色岩系在我国华北、华南及塔里木盆地等广泛发育,但富有机质泥页岩的分布特征及其控制因素未有定论。本文对黔北地区下寒武统牛蹄塘组(及同时期地层)不同沉积相带典型剖面中的富有机质泥页岩及其上下层位进行了地球化学分析,识别出寒武纪早期不同沉积相带氧化还原环境的明显差异。台内凹陷相主要岩性为黑色页岩,底部为不等厚的薄层磷块岩和硅质岩或硅磷质结核,沉积的黑色页岩厚度大,有机质丰度高,V、Ni、Mo、U等微量元素显著富集,反映了贫氧-缺氧环境,以及短暂动态的硫化环境,Mo/TOC反映了其为局限盆地特征;上斜坡相为贫氧到氧化的沉积环境,但更多地是表现为氧化的沉积环境,其中牛蹄塘期存在局部的硫化环境,沉积的黑色页岩厚度小,但有机质丰度最高,V、Ni、Mo、U等微量元素的富集程度较低;盆地相为黑色硅质岩与富有机质的黑色硅质页岩间互沉积,同期沉积厚度较小,有机质丰度相对较低,V和U的富集程度大于台内凹陷相,而Ni和Mo的富集程度则低于台内凹陷相,指示了缺氧环境,期间伴随有贫氧和短暂的氧化环境存在,且可能存在局部的硫化环境,Mo/TOC反映了中等的局限程度。总的来说,黔北下寒武统黑色岩系的有机质丰度、厚度以及微量元素富集程度等特征主要受控于不同的氧化还原环境。     

湘鄂西寒武系烃源岩地球化学特征与沉积环境分析

通过对湘鄂西从台地-斜坡-盆地3条典型寒武系剖面烃源岩微量元素及有机碳含量（TOC,%）的分析,V/(V+Ni)、U/Th、Ni/Co表明寒武系整体上由强还原环境-氧化环境演变,且斜坡带具多个较明显的氧化还原沉积旋回;烃源岩样品稀土元素经北美页岩标准化后δEu为正异常,δCe为负异常,异常程度指示从台地-斜坡-盆地水体加深,寒武系先快速海侵后整体海退。寒武系牛蹄塘组底部烃源岩发育于高生产力、强还原的海侵环境;其有机碳高度富集可能是震旦-寒武纪之交沿伸展断裂上涌的富营养元素的还原性热液以及阵发性上升流等多重因素共同作用的结果。     

安徽石台地区下寒武统黑色岩系微量元素地球化学特征

黑色岩系成因复杂,且与多金属元素成矿密切相关。对安徽石台地区下寒武统黑色岩系微量元素地球化学研究表明,其富集Ag、V、U、Mo、As、Sb等多种金属元素。且在这套黑色岩系地层剖面中,其中部碳质页岩的金属元素富集程度比其它岩性的富集程度明显偏高。微量元素组成及相关元素比值显示这套黑色岩系形成于海相热水沉积作用,代表了一种非正常海水沉积。沉积环境由早期缺氧的还原环境逐渐向后期的半还原-氧化环境演化,反映早寒武世安徽下扬子海由海侵向海退的逐渐过渡。     

塔里木盆地西北缘玉尔吐斯组黑色岩系沉积环境演化及其对有机质富集的控制作用

通过对塔里木盆地西北缘下寒武统玉尔吐斯组沉积地层特征及地球化学分析，研究了玉尔吐斯组沉积时期水体氧化-还原环境及初级生产力的变化特征，探讨了玉尔吐斯组黑色岩系有机质富集机制及烃源岩分布的主要控制因素。塔里木盆地西北缘玉尔吐斯组可分为5段：底部黑色含磷硅质岩段，下部黑色泥岩段，中部灰色白云岩段，上部黑色页岩与灰色微晶灰岩互层段，顶部浅灰色粉晶白云岩段。它们构成一个完整的海侵-海退沉积旋回。氧化-还原指标及热液示踪参数显示玉尔吐斯组黑色岩系不同层段的形成环境存在差异：底部硅质岩形成于缺氧环境，热液活动显著；下部黑色泥岩形成于强缺氧硫化环境，热液活动较强；上部黑色页岩形成于贫氧-氧化环境，热液活动较弱。综合研究表明：玉尔吐斯组黑色岩系沉积时期，水体先变深后变浅，氧逸度先降低后升高，古生产力逐渐减弱，在缺氧的水体条件和热液作用主导的高生产力综合控制下形成了以玉尔吐斯组下部黑色泥岩为代表的优质烃源岩。     

南秦岭地区下寒武统水沟口组黑色岩系成因及其沉积环境

早寒武世全球广泛发育的黑色岩系记录了重要海洋环境信息。为了解决该时期黑色岩系成因模式和沉积环境问题,本文选取南秦岭淅川—内乡地区下寒武统水沟口组黑色岩系为研究对象,通过剖面详测、薄片鉴定、电子探针和主微量元素等岩石学-地球化学分析方法,对其物质来源、形成机制和沉积环境进行分析。研究表明:水沟口组黑色岩系普遍具有海相硅质岩典型特征—微晶石英结构,并具有与海水一致的稀土标准化曲线和低的总稀土值,指示其形成于海水环境;电子探针下发现黑色岩系富含与热液有关的重晶石、萤石矿物,和与生物相关的磷灰石、黄铁矿矿物,同时黑色岩系成因判别图解中绝大部分样品落入生物成因区域,少数落入热液成因内,指示硅质来源以生物成因硅为主并含少量热液硅;样品高V/(V+Ni)、Ni/Co比值和氧化还原敏感元素(Mo、U、V等)不同程度富集指示较强的还原环境,结合黑色岩系形成环境判别图得出该套岩系形成于大陆边缘—深海盆地区域内还原—缺氧的滞流水体环境。综上得出水沟口组黑色岩系形成时洋底热液活动频繁,深部流体上涌带来大量营养物质使得浅海生物繁盛,海水中硅在生物作用和热液影响下促使硅质胶体颗粒化学沉淀,并随洋流在远离热液中心的大陆边缘位置沉积成岩。早寒武世还原—缺氧性质海水和微生态系统有助于硅质沉淀,而微生物富硅作用促进了黑色岩系形成。     

贵州遵义板桥剖面奥陶系湄潭组黑色页岩沉积环境条件判识及烃源意义*

华南上扬子地区下奥陶统湄潭组是一套厚度较大的泥页岩沉积,黑色页岩十分发育,但对其沉积环境的认识争议较大。文中以贵州遵义板桥剖面为例,通过对黑色页岩及其共生岩石的沉积特征及地球化学特征的综合研究,着重分析湄潭组黑色页岩沉积期的相对水深、沉积水动力条件以及古海水物理化学性质等沉积环境条件。结果表明: (1)板桥剖面湄潭组黑色页岩以颜色暗黑和水平纹理发育良好为显著特征,不产出宏体生物化石,主要以与生屑灰岩或钙质粉砂岩不等厚频繁互层的共生形式产出,说明湄潭组黑色页岩应该不是深水环境的沉积产物,而是在混积台地内低能的浅水泥质潟湖环境中沉积的;(2)与黑色页岩互层的生屑灰岩层段多发育下细上粗的逆粒序结构,顶部可见铁质氧化物,钙质粉砂岩则多发育浪成交错层理和生物钻孔,均呈现出浅水沉积特征;(3)黑色页岩的V/(V+Ni)、Th/U、V/Cr以及Ni/Co的平均值分别为0.71、5.52、1.07和2.04,均指示次氧化—氧化环境;Sr/Ba值介于0.11~2.20之间,平均值为0.55,指示淡水—半咸水环境;(4)生屑灰岩的部分层段可见明显的侵蚀面,镜下可见岩溶发育,同时其REE配分形态趋于水平,∑REE值较高、Y/Ho值较低,具暴露岩溶特征;(5)黑色页岩TOC值介于0.09%~1.05%之间,平均值为0.39%,恢复的原始TOC含量介于0.28%~3.16%之间,平均值为1.25;R_O平均值为2.095,有机质类型主要为腐泥型。综合上述分析结果,认为遵义板桥剖面湄潭组黑色页岩为一套形成于浅水、次氧化-氧化环境的有效烃源岩,高的古生产力是有机质富集的主要原因。研究结果为判识川南地区湄潭组黑色岩系沉积环境和生烃潜力提供有力的证据,也为浅水成因黑色页岩沉积环境条件判识研究提供了一个新的实例。     

渝东北陡山沱组碳酸锰微生物岩沉积环境初探

沉积型碳酸锰矿床多被认为沉积于水体较深、局限且较还原的沉积环境,特别是黑色页岩型碳酸锰矿床。在扬子北缘城口地区,埃迪卡拉系陡山沱组顶部黑色页岩中也发育碳酸锰沉积,黑色页岩及锰矿石Ce元素异常被认为是指示沉积环境的关键证据,但缺乏系统的沉积学证据,其沉积环境还存在争议。本次研究通过野外剖面、钻井岩心观察和室内薄片观察,详细描述了城口地区陡山沱组碳酸锰岩石的沉积结构、构造特征,对其展开了详细的沉积学研究,确定了其沉积环境并建立了沉积模式。研究表明,城口锰矿是典型的微生物岩沉积,菱锰矿以层状构造为主,内部发育叠层石、核形石、树形石以及凝块石。其中,核形石菱锰矿常黏结生长,菱锰矿微观特征记录了凝块状、球粒状、丝状、管状、纤维状以及放射状等微生物岩微结构。关键钻孔岩心沉积记录显示,研究区陡山沱组菱锰矿与胶磷矿交互沉积,菱锰矿中发育各种微生物岩旋回沉积,少见正粒序层理,内部偶有记录代表水动力变强的内碎屑层,而胶磷矿以强水动力内碎屑沉积为特征,常发育于菱锰矿上部,显示含锰岩系—含磷岩系旋回沉积特征,揭示陡山沱组末期城口地区沉积水体逐渐变浅的特征。结合区域陡山沱组地层沉积特征,认为扬子北缘城口地区陡山沱组1段为缺失盖帽的无障壁海岸沉积,陡山沱组2段是具有混积特征的碳酸盐岩缓坡沉积,微生物岩型菱锰矿主要发育于浅缓坡下部障积丘礁沉积环境。值得注意的是,研究区陡山沱组末期障积丘礁的发育是加速该区域沉积体系由缓坡向台地演化的重要盆地演化动力学因素。     

塔西南坳陷古新统阿尔塔什组蒸发岩沉积旋回特征及控制因素探讨

塔西南坳陷古新世初期广泛发育厚层蒸发岩沉积。阿尔塔什组蒸发岩为断续海侵环境下的产物,依据海侵范围扩大时蒸发岩系地层中出现的多套泥岩、泥灰岩沉积为标志,选取了坳陷内8口钻孔剖面进行沉积韵律划分及沉积旋回的识别和对比,在古新世阿尔塔什组沉积期共识别出4期次级蒸发岩沉积旋回,每个旋回基本呈现蒸发岩-泥灰岩的岩性变化,这种沉积韵律的交替转变可能与4次小规模的海侵-海退事件密切相关。钻孔剖面对比结果显出,次级沉积旋回在各钻孔中的发育情况有所不同:研究区西部钻孔多发育完整的4期沉积旋回,至Ks101井附近识别出3期,麦盖提斜坡只圈定出Ⅱ3、Ⅱ4期旋回,普遍缺失了前两期沉积旋回。在沉积旋回发育状况及厚度方面同样显示出东西向差异。研究表明,坳陷内蒸发岩沉积分布具有自西向东拓展的趋势,其沉积中心逐渐由西昆仑山前的Wx1、Wb1井一带迁移至坳陷东部麦盖提斜坡的Tc2井附近。前陆盆地基底形态和海侵-海退旋回的综合作用是造成这种变化的主要原因。最后,结合各钻孔位置及蒸发岩分布迁移特征,指出阿尔塔什期海侵过程具有阶段性,海域分布范围自西昆仑山前向东南逐渐扩展,最终遍及整个塔西南坳陷。     

湘黔地区中奥陶世海平面上升的沉积响应

中奥陶世克拉道克阶(Caradocian)在全球范围内为海侵期,体现在全球范围广泛的黑色页岩沉积及笔石动物的大规模繁盛,湘黔地区这一时期地层发育完全,从碳酸盐台地-斜坡-外陆架盆地均有不同程度的响应。在台地区表现为碳酸盐台地的淹没,斜坡区表现为碳酸盐重力流及黑色页岩、粉砂岩沉积,形成碳酸盐与陆源碎屑的混合沉积,而在外陆架盆地区表现为黑色岩系大规模发育及笔石的大量繁盛。     

湘西下寒武统牛蹄塘组黑色岩系的微量元素地球化学特征

为探讨下寒武统黑色岩系在深水区域的沉积环境及其伴生的Ni-Mo多金属富集层的金属元素来源,对湘西寒武纪初期盆地相区龙鼻嘴剖面进行系统采样,分析了样品中干酪根的微量元素含量和全岩V、U、Mo与TOC含量并就微量元素比值与TOC关系进行了探讨。结果显示,干酪根中的Th/U、V/Sc和V/Cr值在剖面上均具有相似的变化规律,V、U和Mo与TOC的相关性可知剖面沉积过程中存在硫化环境,Ni-Co-Zn三角图解中多数样品分布于热水沉积区域。初步推断剖面下部的NiMo多金属富集层,其具有微量元素明显富集和碳同位素较大负值的特征,可作为地层对比的标志;寒武纪初始阶段深水区域可能处于短暂的硫化环境,伴随着沉积环境的充氧之后变为广泛的厌氧环境;黑色岩系沉积过程中有热液活动参与,Ni-Mo多金属富集层中部分元素的极度富集可能是还原的海水和海底热液共同作用的结果。     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.     

郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

塘口水电站坝基岩体透水性和渗漏问题分析

塘口水电站大坝基础座落在断层和裂隙较发育的龟裂纹灰岩上,岩体完整性差、透水性强,多年运行后,大坝灌浆廊道和排水廊道出现多处集中性漏水,为确保大坝安全和电站正常发电,根据渗漏性质和成因,采用对灌浆廊道补充帷幕灌浆,对排水廊道进行固结+帷幕+回填灌浆。通过灌浆处理后,效果良好,表明灌浆工程有效的将导致坝基渗漏的上下游的裂隙通道封闭,并顺利的经受了随后的汛期洪水考验,大坝安全得到保障。     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Calculation of the Inverse of the Covariance

In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix.     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。      

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.