甘肃兰州-民和盆地中铺地区下白垩统河口群沉积特征及其盆地分析意义*

甘肃兰州-民和盆地是中国西部典型的陆内断陷沉积盆地,该盆地发育的下白垩统河口群是一套以红褐色为主的碎屑岩地层。依据野外调查,以盆地分析方法为手段,从地层、沉积相、物源和古水流等方面入手对盆地东南部的中铺地区河口群进行了沉积环境的系统分析。通过对研究区内河口群沉积相、沉积构造和沉积序列的研究,认为整套地层垂向上发育有冲积扇相-辫状河相-曲流河相沉积,并进一步划分出若干微相;同时结合该地区的物源和古水流分析认为,早白垩世研究区内的物源主要来自南部的祁连山多旋回造山带;盆地内的下白垩统河口群在不同地区呈现出不同特点,并以此建立了兰州-民和盆地早白垩世古地理格局及盆地演化模式。     

兰州-民和盆地河口群层序地层格架特征及盆地演化

兰州-民和盆地河口群形成于早白垩世，其间充填了巨厚的陆源碎屑物，碎屑物的组合内容和方式反映了冲积扇相，扇三角洲相，湖泊相沉积体系占主导，盆地地层层序具有退积型。加积型，进积型叠置的变化旋回，显示了全韵律的特点。代表了构造旋回幕的产物。根据盆地的发展演化特征和层序界面的确定，初步建立了盆地的层序地层格架，同时阐述了盆地的演化过程。     

兰州-民和盆地下白垩统河口群沉积序列及沉积相研究

兰州—民和盆地下白垩统河口群是一套厚度巨大的陆相碎屑岩沉积，根据岩性组合和沉积旋回，自下而上将河口群划分为8个非正式的组级单位。通过对河口群基本层序的分析和沉积序列及沉积相的研究，可以识别出冲积扇相、三角洲相和滨浅湖相3类相环境，细分为13种微相。沉积相的演变从整体上反映了整个盆地的演化过程。河口群的沉积环境由冲积扇相→三角洲相→滨浅湖相→三角洲平原相演变，形成了一个完整的序列，反映了盆地从开裂→扩张→萎缩→消亡的不同发展阶段。     

甘青间民和盆地的河口群

<正> 甘青间民和盆地的河口群出露较广,西起西宁以北,互助—石湾一线,东至兰州以东,皋兰县泥湾—黑石川一带。主要见于湟水、黄河两岸。下面介绍六个剖面:     

民和盆地中,新生代红层的划分与对比

民和盆地中、新生代红层在甘肃有一定的代表性,对其进行划分对比有利于资源的勘探开发。本文根据红层的沉积韵律、古生物组合等原则,将民和盆地中、新生代红层自下而上划分为中侏罗统享堂组、上侏罗统大通河群、下白垩统河和群、上白垩统民和组、下第三系西宁群、中新统咸水河组等六个岩石地层单位。     

兰州-民和盆地第四纪地层学研究

在野外调查和室内分析的基础上,对兰州-民和盆地的晚新生代地层和环境进行了较系统的研究,对第四纪地层进行了地貌学、岩石学、年代学、土壤地层学和古气候学研究,查明了研究区各地貌单元形成时代与物质组成特点、侵蚀期与堆积期的旋回过程及黄土中1.9MaB.P.以来磁化率与古气候、古土壤事件(S26-S0)、古气候演化的周期(45ka、100ka)、特点和黄土中15万年以来短尺度气候事件(H1-9及DO1-10).     

甘肃省的白垩系

依据地层区划分原则,将省内白垩系划分为北山、走廊、潮水、祁连、兰州、陇东、西秦岭区7个地层区和酒泉、武威、六盘山、陕甘宁盆地4个地层分区;分别建立了老树窝群、新民堡群、庙沟群、河口群、志丹群、六盘山群、东河群、金刚泉群、马莲沟群、民和组10个群级岩石地层单位;详述了各建群、组的代表剖面;以“热河动物群”、茹福德蕨-拟金粉蕨植物群存在的最低层位的新民堡群、志丹群及与其相当地层的底界,确立为白垩系的底界。以含具冠女星介生物组合的民和组的顶界为白垩系的顶界;按地层区总结了生物组合特征,并与国内外有关生物组合进行了对比,以此确定了省内白垩系的时代。     

兰州盆地永登剖面记录的第三纪沉积环境

对兰州盆地永登剖面第三系沉积进行了沉积学研究、并结合年代学研究结果分析了新生代以来沉积环境变化与气候变化.古新世末至早始新世沉积了一套扇三角洲相沉积(细柳沟组),为具交错层理的砖红色砂岩,顶界年龄约51 Ma.兰州地区在51 MaB.P.经历了一次大的环境变化,气候由相对温暖湿润转为半干旱半湿润,气候炎热,湖盆由淡水湖转为盐湖,蕴示着由副热带高压控制的干旱带北移,兰州地区进入受行星风系控制的干旱带.早始新世晚期至早渐新世早期(51～31.5 Ma B.P.),在近20 Ma时间内经历了微咸湖-盐湖阶段(野狐城组),砂泥岩沉积中含有大量石膏夹层.早渐新世,兰州地区向湿润方向转化,兰州盆地由咸水湖转化为淡水湖,可能反映了东南季风逐渐形成,中国大陆由早先行星风系控制转化为季风控制,前期东南方向干旱带消失,西北干旱带出现,兰州地区相对早先湿润.早渐新世中期至中中新世(31.5～15 Ma B.P.),兰州盆地在经历了三次大的沉积旋回后湖盆逐渐干枯,三个大旋回分别由河流相砂岩-微咸水滨湖相砂泥岩、泛滥平原相泥岩,河流相砂岩-淡水滨湖相砂泥岩-沼泽相、泛滥平原相泥岩,河流相砂岩-沼泽相、泛滥平原相泥岩组成.20 MaB.P盆地接受大量砂砾石沉积,反映出周缘山体快速抬升遭受剥蚀,可能蕴示着青藏高原抬升波及到兰州地区.     

兰州--民和盆地首次发现白垩纪恐龙足印化石

兰州—民和盆地是我国西北地区的一个较大的中新生代盆地,广泛分布着巨厚的白垩纪—第三纪河湖相地层。其中,第三纪地层中的生物化石十分丰富,而白垩纪地层中十分稀少,除微体化石外,未发现任何具有地层意义的宏观生物化石。从而影响对该地区中生代生物演化、地层划分...     

兰州盆地下白垩统碎屑岩层序地层序列：祁连山早白垩世隆升的沉积学响应

青藏高原东北缘的祁连山,在早白垩世期间发生明显隆升,受区域性构造运动和白垩纪特殊行星风系的影响,在山前盆地中沉积了一套特殊的碎屑岩序列。兰州盆地下白垩统发育完整,虽然局部被第四系覆盖,但总体出露良好,其特殊的相序单元构成的非常规体系域概念框架下的陆相层序地层学模式,对研究祁连山隆升的沉积学响应及环境效应具有重要意义。兰州盆地下白垩统为河口群,可以识别出5个三级层序(S.1—S.5),包括LAST和HAST两个非常规体系域,冲积扇和河流相粗碎屑沉积构成三级层序的LAST单元,HAST单元由湖泊相细碎屑地层组成。河口群上部地层发育的风成砂岩序列,在一定程度上可以解释为祁连山隆升造成的"焚风效应"产物,对研究祁连山的阶段性隆升特征具有重要的意义。早、晚白垩世之交,祁连山开始快速强烈隆升,兰州盆地整体抬升为剥蚀区,导致研究区缺失上白垩统。因此,兰州盆地下白垩统特殊的层序地层序列,不仅是早白垩世祁连山隆升的物质记录,还为研究早白垩世东亚大气环流格局变化提供了物质基础。     

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。     

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.     

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。      

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。     

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.     

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.     

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″.     

Artemia in the Salt Lakes of Russia:the Productivity of Populations,the Reserves of the Cysts and the Fisheries

正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the