库车坳陷中部新近系-第四系砾岩层的沉积特征及分布规律

为了解决库车坳陷新近系-第四系砾岩层引起的速度变化和工程决策问题,利用砾岩层野外露头和钻井岩屑等资料,对砾岩层的沉积特征及分布规律进行了系统研究。分别对野外砾岩层和钻井岩屑的厚度、岩性、结构构造及砾石成分进行统计分析,在区域上对各层系的砾岩层进行划分和对比。认为库车坳陷新近系-第四系砾岩层可以划分为四期,具有冲积扇、扇三角洲及冲积平原三种沉积成因,它们的规模、水动力条件及沉积构造等具有较大差异。以冲积扇砾岩层规模大,发育四大物源体系,各物源体系的砾石成分分区明显,砾石粒径随相带分异。库车坳陷砾岩层整体具有纵向上多期次连续发育、相带差异明显,横向上相变快、集中分布的特点,新生代构造演化、构造样式及南北向断裂是控制砾岩层发育、沉积特点及分布规律的主要因素。     

库车坳陷中部新近系一第四系砾岩层的沉积特征及分布规律

为了解决库车坳陷新近系一第四系砾岩层引起的速度变化和工程决策问题,利用砾岩层野外露头和钻井岩屑等资料,对砾岩层的沉积特征及分布规律进行了系统研究.分别对野外砾岩层和钻井岩屑的厚度、岩性、结构构造及砾石成分进行统计分析,在区域上对各层系的砾岩层进行划分和对比.认为库车坳陷新近系一第四系砾岩层可以划分为四期,具有冲积扇、扇三角洲及冲积平原三种沉积成因,它们的规模、水动力条件及沉积构造等具有较大差异.以冲积扇砾岩层规模大,发育四大物源体系,各物源体系的砾石成分分区明显,砾石粒径随相带分异.库车坳陷砾岩层整体具有纵向上多期次连续发育、相带差异明显,横向上相变快、集中分布的特点,新生代构造演化、构造样式及南北向断裂是控制砾岩层发育、沉积特点及分布规律的主要因素.     

云南弥渡地区新近系三营组砾岩层砾组特征及其地质意义

通过对云南省弥渡地区哀牢山断裂带两侧的两个小型盆地内新近系三营组砾岩层砾性、砾度、砾态和砾向等的详细研究与分析,结合盆地基岩地层特点和周边构造带的岩性组合特征。对比了两盆地的砾岩层组合特征,得出两者皆为半干旱—干旱古气候条件下形成的沉积盆地,其中南涧盆地为一套冲积扇—河流相粗碎屑沉积,具有快速堆积的特点,其砾石成分组合在盆地不同位置有较多的差异,反映了其物源供应条件较复杂;而金宝山盆地虽也呈现冲积扇—辫状河—洪积相粗碎屑沉积的特性,但其砾岩组合特征表明水动力条件相对南涧盆地弱,且砾石层沉积前砾石遭受了较强的物理化学作用。就盆地基岩及周边地层岩性特点,结合砾石扁平面倾向统计,南涧盆地砾石主要来自盆地基底及周边高山,而金宝山盆地的砾石则主要来自盆地内部的基底地层及其西缘的哀牢山构造带。     

江西抚崇盆地晚白垩世-古新世莲荷组砾石砾组分析

赣杭构造带中、新生代红色粗碎屑岩发育,对红层中砾石组构分析有助于理解红盆形成、演化过程.运用砾组分析方法,对江西抚崇盆地晚白垩世—古新世莲荷组砾岩层的砾性、砾度、砾态及砾向进行分析,并在此基础上对研究区红盆砾岩的物质来源、成因和形成条件等进行综合判断.研究结果表明,莲荷组砾岩为晚白垩世—古新世半干旱—干旱条件下的一套冲积扇相粗碎屑沉积,具有多物源和快速堆积的特点.总体上,砾石成分复杂,风选程度较差,呈次棱角—次圆状,风化程度较低.盆地不同地区砾石成分组合特征具有明显差别,反映了盆地周围复杂的物源供应条件.根据盆地周边出露基岩地层和扁平状砾石产状统计玫瑰花图判断,莲荷组沉积时期,物源主要来自盆地内部的基岩地层以及盆地西南部、西部和东北部.     

云南省南涧地区下白垩统南新组砾岩层 砾组特征及其物源意义

该文通过对哀牢山构造带西侧云南省南涧地区下白垩统南新组砾岩层的砾性、砾度、砾态和砾向等的详细研究与分 析,结合盆地基岩地层特点和周边构造带的岩性组合特征,发现南新组砾岩总体上具有砾石成分复杂、分选性较差、磨圆程 度中等-较好（次圆状-圆状）、风化程度较低等特征;探讨了砾岩层本身的性质、物质来源,以及砾石沉积时盆地的水动力条 件、气候环境、古地貌特征和构造条件。认为南新组砾岩层为半干旱-干旱古气候条件下的一套冲积扇-辫状河相粗碎屑沉 积,具有快速堆积的特点;砾岩层沉积前砾石遭受了较强的物理化学作用。根据盆地基岩及周边地层岩性特点和砾石扁平面 倾向统计,砾石的主要来源是盆地内部的基底地层及其东缘的哀牢山构造带。     

山西榆社盆地新近系马会组砾岩层砾组特征及其地质意义

通过对山西榆社盆地新近系中新统马会组砾岩层的分布特征、剖面特征和砾组特征分析,结合盆地内部和四周山区的岩性特征分析,阐述了砾岩层本身的性质、成因、来源和搬运方式等,探讨砾石沉积时盆地的水动力条件、气候环境、地貌特征和构造条件等。研究表明,马会组砾岩层为榆社盆地新近纪河湖相沉积的底砾岩,其中所含的3层砾岩在成因、来源、搬运和沉积环境上具有较好的一致性。马会组砾岩层为多期次、多来源、非稳定的冲湖积成因,为湖泊水进期的沉积物,指示干冷向温湿转变的气候环境;砾石的主要来源是盆地内部的基底地层及其东缘、北缘和西缘的山区;砾石遭受了较强的物理化学作用,还存在一定的生物作用;含量较少的花岗岩砾石经受了较长距离的搬运,其他岩性砾石经受了近—中距离的搬运。榆社盆地为喜马拉雅运动二幕晋东地区山地相对抬升形成的山间盆地,砾石沉积时已形成了中间低、四周高的盆地雏形。     

青藏高原东缘晚新生代成都盆地物源分析与水系演化

成都盆地位于青藏高原东缘,夹于龙门山与龙泉山之间,盆地中充填了3.6Ma以来的大邑砾岩、雅安砾石层和晚更新世—全新世砾石层,其物源均来源于盆地西侧的龙门山,具横向水系和单向充填的特征。本次以物源区分析作为切入点,以岷江和青衣江水系为重点,采用砾岩成分分析、砂岩岩屑成分分析、重矿物分析和砾石的地球化学分析等基本方法,开展青藏高原东缘晚新生代以来的古水系重建工作,研究结果表明,成都盆地主要有两个物源区,其中成都盆地北部的都江堰街子场、崇州白塔山、大邑白岩沟、大邑氮肥厂、彭州丁家湾、彭州葛仙山等剖面中的砾石层在碎屑成分、重矿物和花岗岩砾石的地球化学成分等方面相似,应为古岷江的产物,而其与现代岷江在砾岩成分和重矿物特征等方面的差异性则表明古岷江可能存在改道的现象;成都盆地南部的庙坡剖面和熊坡东剖面中的砾石层在碎屑成分、重矿物和花岗岩砾石的地球化学成分等方面相似,应为古青衣江的产物,但其流向却与现代青衣江的流向不同,表明熊坡背斜是在大邑砾岩沉积之后隆起的,它的隆起迫使古青衣江改道。     

西天山温泉北中新统塔西河组下部砾岩特征及意义

博乐盆地地处西天山造山带北部,是盆山耦合研究的理想场所。笔者以温泉北阿茨—科茹尔太一带中新统塔西河组为研究对象,进行地层组成、砾石成分、砾石砾径分析,探讨砾岩成因,浅析其构造背景、物源组成及其对沉积型铀矿成矿作用的意义。研究区塔西河组可分为上部的泥岩层、下部的砾岩层。下部砾岩层主要由灰白色花岗岩质角砾岩组成,局部为灰色凝灰岩质角砾岩、浅红色凝灰岩花岗岩质砾岩。砾石结构、成分、对砾径等分析结果显示,下部砾岩层为冲积扇成因,并以泥石流成因为主,局部为冲积河道成因。结合区域地质资料,研究区中新统塔西河组下部砾岩层为西天山始于晚新生代(24～25Ma以来)构造隆升-剥露事件的沉积响应,物源区为盆地北侧的阿拉套山,其所代表的快速抬升事件掀斜较早形成的地层,使花岗岩大面积出露,为前期已形成砂体中铀的二次富集及后期形成的泥岩中铀的富集提供铀源,对泥岩型铀矿、砂岩型铀矿成矿作用具有重要意义。     

内蒙古大青山煤田晚古生代砾岩的沉积特征

大青山煤田晚古生代地层中有 1 4层沉积砾岩。其中,晚石炭世地层中赋存 8层,二叠世 6层。通过对这些砾岩层的野外测量、室内岩矿鉴定等综合分析研究,查明晚石炭世的砾岩几乎全是稳定的单成分砾岩,石英砂岩和燧石质砾石的含量高达 93 %以上,砾石最大扁平面均向南倾,倾角在 5° - 1 0°之间,与砾岩伴生的粗粒石英砂岩发育大型低角度双向交错层理,萨胡环境判别参数等特征表明晚石炭世砾岩为滨海环境下的产物。二叠世的砾岩则主要是复杂成分的砾岩,尤其是早二叠世晚期及晚二叠世初期形成的 2层砾岩中砾石种类达 1 5种,以中酸性火山岩和火山碎屑岩砾石为主,并含较多量的变质岩和中酸性侵入岩砾石,砾岩层各种特征表明二叠世砾岩为河流相产物。大青山煤田晚古生代沉积砾岩的形成与北部造山带的隆升密切相关,它们是前陆盆地的沉积产物。     

北票盆地侏罗纪砾岩沉积特征及对区域构造演化的指示

陆相盆地充填沉积物中砾岩沉积特征分析是示踪物源及反演源区构造演化背景的重要手段之一。通过对辽西北票盆地侏罗系的砾岩层沉积特征及砾岩的分散型式分析发现，北票盆地砾岩的沉积特征明显受到火山作用的影响，物源主要以盆地前期或同期火山岩及西缘前中生代沉积地层和变质岩系为主，砾石成分组成自下向上表现出一定的规律性变化，与盆地两次大的火山－沉积作用旋回有很好的对应关系，表现为从沉积早期以火山岩砾石为主向晚期以沉积岩及变质岩砾石为主的演化过程。早侏罗世晚期及晚侏罗世晚期砾岩主要为复成分砾岩，松散堆积，填隙物主要为泥砂质．分散型式为混合型，应为盆地在侏罗纪经历的两次大的逆冲推覆作用的沉积响应。中侏罗海房沟组巨厚的粗砾岩沉积对应于盆地西缘的一次快速隆升事件。     

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.