东非鲁伍马盆地深水区构造-沉积演化过程及油气地质特征

利用深水区的二维、三维地震资料开展构造-沉积演化研究,鲁伍马盆地二叠纪—早侏罗世为冈瓦纳陆内—陆间裂谷活动期,发育河流—湖泊沉积;中侏罗世—早白垩世为马达加斯加漂移期,位于剪切型大陆边缘,发育海陆过渡相沉积;晚白垩世—渐新世为被动大陆边缘期,深水沉积广泛发育,重力流沉积延伸至戴维隆起带;中新世—第四纪为东非裂谷海域分支活动期,陆坡和凯瑞巴斯地堑发育深水重力流沉积。盆地垂向上形成"断—坳—断"结构,二叠纪—早侏罗世及中新世—现今发育两期明显的裂谷活动。马达加斯加漂移期的海相泥岩为深水区的主力烃源岩,古近纪的陆坡深水浊积砂体为主要储层。东非裂谷海域分支的断层活动沟通了下伏烃源岩,晚期断层不发育的西部陆坡成为主要的油气聚集区。     

东尼日尔Termit盆地叠置裂谷的演化:来自构造和沉积充填的制约

东尼日尔Termit盆地是中西非裂谷系中典型的中—新生代裂谷盆地。在充分应用钻井和地震解释资料的基础上,根据构造、沉积充填及主要区域性不整合面的特征,分析了该盆地的演化过程。盆地内主要发育两类断层,第一类断层形成于早白垩世,于古近纪发生继承性活动,第二类断层为形成于古近纪的新生断层。全盆地普遍存在4个主要区域性不整合面,分别位于下白垩统、上白垩统、古近系、新近系—第四系底部。下白垩统和古近系沉积特征受断层活动控制明显,上白垩统和新近系沉积中心位于盆地中部,在其沉积时构造活动较弱。构造和沉积充填特征表明,Termit盆地经历了白垩纪和古近纪—第四纪两期裂谷旋回叠置的演化过程。下白垩统和古近系沉积于同裂谷期,沉积充填受断层活动控制;上白垩统和新近系—第四系沉积于后裂谷期,以热沉降拗陷作用为主。     

转换型被动陆缘盆地地质特征与深水油气聚集规律:以赤道大西洋西非边缘盆地群为例

基于前人成果及油气勘探新发现资料,系统分析了赤道西非受转换断层强烈控制的转换型被动陆缘盆地群地质与深水油气聚集特征。构造解析与地层剖析表明,该地区盆地形态、基底断裂、变形序列和区域应力均受转换断层控制;经历了前转换陆内沉积期、陆内剪切裂谷期、陆洋转换压扭期及被动陆缘热沉降期4个演化阶段;形成4套区域性不整合,从东往西具有迁移性;充填了陆内剪切期河湖相碎屑岩、陆洋转换期陆相及滨浅海相碎屑岩为主和被动陆缘期海相碎屑岩为主的3套地层巨层序。地质结构显示,盆缘窄陆架、陡陆坡,断裂呈高角度张剪性,易发育转换脊或台地。深水沉积特点为小物源短距离近岸快速堆积,形成富砂的纵向叠置横向裙边状小型扇或扇复合体。深水油气勘探以陆洋转换-被动陆缘早期阶段岩性-地层和背斜构造圈闭为重点。     

东非凯瑞巴斯盆地多期构造变形及对油气聚集的控制作用

利用最新的钻井、地震资料,对东非凯瑞巴斯盆地(Kerimbas Basin)进行构造–地层解释和构造演化过程恢复。结果显示,凯瑞巴斯盆地共发育了4期构造变形:(1)二叠纪–早侏罗世晚期的冈瓦纳陆内裂谷活动,全区发生伸展构造变形;(2)早侏罗世晚期–早白垩世晚期马达加斯加向南漂移,全区发生右行走滑变形;(3)新发现晚白垩世局部伸展构造变形;(4)中新世–第四纪的东非裂谷海域分支活动,导致研究区发生第三期伸展构造变形,形成凯瑞巴斯盆地现今地堑形态。三期伸展构造变形的应力方向均为近E-W向,断层展布方向均为近S-N向。每一期构造变形的范围,强度及对沉积地层的控制作用差异显著。凯瑞巴斯盆地控坳断层活动具有继承性。基于研究结果,建立凯瑞巴斯盆地构造成因模式。冈瓦纳陆内裂谷活动有利于二叠系–下侏罗统构造圈闭的形成,并沟通了烃源岩和储层,有利深层油气的聚集;东非裂谷海域分支裂谷活动沟通了前新生界烃源岩和西部陆坡古近系储层,但同时也破坏了盆地内及东部的圈闭。断层不发育的西部陆坡为主要油气聚集区。     

南大西洋两岸被动陆缘盆地结构差异与大油气田分布

以板块构造演化为基础,利用地震、地质等资料,再现南大西洋两岸共轭型被动陆缘盆地原型盆地形成演化过程。首次依据盆地结构差异及沉积充填特征,将研究区被动陆缘盆地进一步划分为“三段”“四类”;结合对已发现大油气田的解剖,搞清了每类盆地大油气田成藏规律,并分别建立了其大油气田成藏模式。认为两岸“三段”“四类”盆地都经过了早期陆内裂谷、过渡期陆间裂谷及漂移期被动陆缘三个原型阶段。南段为下伏裂谷层系比较发育的“断陷型”盆地,上覆坳陷沉积厚度较薄,仅作为区域盖层,形成“裂谷层系构造地层型”大油气田。中段为裂谷、坳陷层系都比较发育且过渡阶段有盐的“含盐断坳型”盆地,以过渡期陆间裂谷盐岩充填为特征,其上、下的漂移期海相及裂谷期湖相页岩均可形成有效烃源岩,海相页岩及盐岩分别作为优质盖层,形成了“盐下碳酸盐岩盐上重力流扇体型”大油气田。北段为裂谷层系分布范围小、坳陷沉积范围广且厚度大的“坳陷型”盆地,受 “窄”陆棚、“陡”陆坡控制,坳陷层系重力流扇体自始至终比较发育,源于坳陷层系下部海相页岩中的油气直接充注于本身内部裙边状分布的重力流复合扇体之中,形成“漂移期重力流扇体群型”大油气田。另外,研究区还发育尼日尔、福斯杜亚马逊、佩罗塔斯三个具有独特构造沉积特征的 “三角洲型”被动陆缘盆地,其特殊性体现在三角洲层系由于沉积速率极高,从陆向海形成生长断裂带-泥岩底辟带-逆冲断裂褶皱带-平缓斜坡带四大环状构造带。除了前三角洲层系可以作为有效烃源岩之外,本身也可以形成自生自储自盖型组合,形成独特的“四大环状构造带型”大油气田,即在由陆向海生长断裂带-泥岩底辟带-逆冲断裂褶皱带-平缓斜坡带四大环状构造带上都可以形成大油气田。     

摩洛哥—西撒哈拉被动陆缘盆地石油地质特征及勘探方向

针对摩洛哥—西撒哈拉具有相似构造和沉积特征的被动陆缘盆地,开展盆地演化、石油地质特征与资源潜力等方面的研究,并指出油气勘探方向。摩洛哥—西撒哈拉被动陆缘盆地经历前裂谷期、裂谷期和后裂谷期3期构造演化,发育多套烃源岩和储层、多种圈闭类型。最重要的烃源岩为后裂谷期侏罗系—白垩系海相泥岩,主要储层为侏罗系—白垩系碳酸盐岩和碎屑岩,圈闭类型以盐构造作用机制下形成的构造圈闭和构造-岩性圈闭为主。摩洛哥—西撒哈拉被动陆缘盆地可划分为3个主要成藏组合,侏罗系和白垩系—新近系成藏组合是最重要的成藏组合。侏罗系碳酸盐岩和白垩系阿尔布阶—塞诺曼阶浊积砂岩是研究区当前的重点勘探领域;深水区白垩系盐构造和斜坡扇形成的地层-岩性圈闭可能为未来的勘探潜力区。     

东非鲁武马盆地始新统超深水重力流砂岩储层特征及成因

鲁武马盆地古近系-新近系发育多套超深水、超大型、富含天然气藏的重力流沉积砂体。以始新统砂体为解剖对象,分析区内重力流砂岩储层特征及成因。结果表明砂体以巨厚层状产出于深海泥岩内部,并与周围泥岩截然接触,测井曲线表现出宏观均一性;岩心揭示此类巨厚砂体是由多期单砂体叠置而成,单砂体是由底部高密度颗粒流和顶部低密度浊流两部分组成,且经历过强底流改造。鲁武马河流三角洲强大物源供给决定了区内砂体分布面积和体积规模;深海滑塌、块体搬运等重力流沉积过程控制了沉积体粒序构造和内部结构;海底区域性强底流持续冲刷并携带走单砂体顶部细粒沉积物,残留了底部“干净”的中粗粒砂岩;多期沉积事件和频繁水道迁移决定了砂体纵、横向叠加展布,并最终形成了区内厚度巨大、岩性宏观均一且连通性极好的超大型深水重力流沉积砂岩储层。     

印尼打拉根盆地油气成藏特征与主控因素

打拉根盆地是印度尼西亚重要的含油气盆地,油气资源丰富。盆地自陆向海划分为陆上反转构造带、陆架区伸展断裂带和深水区逆冲褶皱带,各区带油气成藏与分布特征存在差异。认为盆地油气成藏属烃源岩和输导体系联合控藏。烃源岩控制油气分布格局,中新统煤系为盆地主力烃源岩,生烃中心主体位于陆架区中部,油气主要富集在生烃中心附近的有利构造中。输导体系是不同区带油气成藏的主要控制因素,断裂和构造砂脊是陆上反转构造带油气运移的优势通道,油气主要富集在上新统与上中新统构造砂脊上的反转背斜中;生长断裂是陆架区伸展断裂带油气运移的优势通道,油气主要富集在上新统与上中新统断裂所夹持的断块上;逆冲断裂是深水区油气运移的优势通道,油气主要富集在上新统逆冲背斜中。指出陆架区伸展断裂带勘探潜力最大,深水区逆冲褶皱带勘探潜力次之,陆上反转构造带具有一定勘探潜力。     

东非大陆边缘构造演化过程与油气勘探潜力

近年来,东非大陆边缘油气接连获得大突破,已成为世界油气勘探的热点。与西非和北非相比,东非油气勘探和研究程度均很低,尤其经历错综复杂的构造演化过程后,盆地构造、沉积与油气系统及其三者之间的相互作用关系十分复杂,不利于对东非油气勘探前景的分析和判断。本文通过对东非大陆边缘形成与演化过程的探讨,并结合现今盆地结构和油气发现状况,研究认为,东非大陆边缘先后经历了Karoo陆内裂谷、侏罗—白垩纪裂谷两期裂谷和一期被动陆缘作用阶段。两期裂谷发育多套烃源层系,并与被动陆缘阶段的三角洲-深水浊积扇储层时空上构成较好的油储关系,两者均受控于东非复杂构造演化作用,构造对油藏系统的改造或破坏作用影响了东非油气富集规模和类型。     

滇西兰坪盆地构造演化特征与成矿关系

兰坪盆地于古特提斯末期进入裂谷盆地阶段.燕山末期—喜马拉雅早期,西带发育沟通地幔的铁各断裂组及由西向东逆冲推覆构造,形成区域上第一期导矿、容矿构造;喜马拉雅中期形成斜冲断裂,导致发育由东向西推覆构造,形成盆地东带导矿容矿构造,完成了盆地内最重要的成矿期次.构造演化控制盆地的沉积作用、火成活动.与成矿有密切关系.     

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.     

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.     

Causes of the famine among the rural population of the Sahelian zone of the Sudan

Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators.     

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。     

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。     

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.