吉林省安图县矿山屯锑矿地质特征及成因探讨

矿山屯锑矿在空间分布上严格受断裂构造控制,按断裂构造展布方向划分成北西西向和北北东向两组矿化带,矿体主要赋存在北北东向矿带中,矿体呈脉状和含矿角砾岩体状出现。根据成矿物质来源、成矿温度及成矿机制的分析,认为该矿床的成因为岩浆期后中-低温热液矿床。     

东秦岭二郎坪地堑金成矿控制因素及富集规律

东秦岭二郎坪地堑位于河南内乡夏馆-西峡二郎坪地区,大地构造单元属于华北板块南缘晚元古代-加里东期增生体,南北均有区域性深大断裂控制.区内金矿广泛分布,以热液叠加改造型为主.金矿床形成主要受含矿地层、构造、岩浆活动和高热流场控制,火山(沉积)地层提供了大量成矿物质,岩浆活动提供了热能和部分成矿物质,构造活动提供热液通道、成矿动力和成矿空间.     

新疆叶城县叉路口铅锌矿床地质特征及矿床成因讨论

新疆叶城叉路口铅锌矿是喀喇昆仑北麓的叶尔羌河上游的一处中型铅锌矿床。铅锌矿体产于神仙湾二叠-三叠纪边缘裂陷带的中-下二叠统神仙湾组上段中,矿体的围岩有碎裂状的粉砂质板岩、白云质大理岩、泥晶灰岩,以及构造角砾岩等,铅锌矿体受断裂及碎裂化岩石的控制,矿体主要呈层状、似层状或大透镜状,但也有小型脉状含矿石英脉穿切层理,矿石构造有条纹-条带状、块状构造、团块状、斑点状、浸染状构造,矿物组合显示简单硫化物组合特点,围岩蚀变主要有硅化、绿泥石化和碳酸盐化,蚀变强度较弱。铅锌矿床特征既反映出沉积成矿的某些特点,也显示出后期热液成矿的许多特征,在综合对比区域铅锌矿成矿规律之后认为,叉路口铅锌矿的矿床成因为沉积-热液改造型铅锌矿床,属于复因-后成矿床范畴。     

甘肃龙首山地区芨岭铀矿床隐爆角砾岩发现及成因探讨

钠交代岩型铀矿是甘肃龙首山地区主要的铀成矿类型之一,研究表明该类型铀矿的含矿主岩为热液隐爆钠交代角砾岩,其分布总体上受近东西向断裂及其分支断裂控制,呈带状分布,构成不规则状的隐爆钠交代角砾岩带。在剖面上,隐爆钠交代角砾岩呈筒状或漏斗状,其控制了钠交代岩型铀矿体的分布。文章认为它是由花岗质岩浆房产生的富气富钠热液运移至压力骤减部位时,发生爆腾形成隐爆钠交代角砾岩,碳酸铀酰络合物([UO2(CO3)]4-)分解卸载成矿物质成矿,同时对围岩产生了钠长石化、绿泥石化、碳酸盐化、赤铁矿化、泥化和硅化。指出按隐爆钠交代角砾岩型找矿模式对该区下一步找矿工作具有较大的指导意义。     

辽宁省铧子峪菱镁矿地质特征及成矿模式

铧子峪菱镁矿位于辽宁省海城境内,形成于古元古代,含矿建造为古元古代辽河群大石桥组三段含镁大理岩.通过对矿区内含镁大理岩中微量元素的分析和对大石桥期岩相古地理、古气候环境等的研究,总结出铧子峪菱镁矿的成矿模式：菱镁矿矿质来源于干热的湖盆地内含Mg质较高的水体,随着蒸发作用的不断进行,菱镁矿原始矿源层逐渐沉积形成,后期的区域变质作用使原始矿源层富集成矿,从而形成了该沉积变质型超大型矿床.     

河北丰宁牛圈银金矿床构造地质特征

牛圈银金多金属矿,华北地洼北缘。成矿条件明显受燕山晚期地洼活动－陆壳伸展运动所形成的断裂构造和火山机构控制,矿床呈隐爆角砾岩筒状,具浅成低温热液型矿床特征。     

辽宁省青城子铅锌矿田成矿特征与矿床成因探讨

青城子铅锌矿成矿受层位、岩性控制.古元古代条痕状花岗岩侵位而引起的穹隆构造及其上覆的层状岩系中的滑脱型韧性剪切带、层间断裂带及中生代岩浆作用、断裂构造对成矿起重要作用.矿床具有“多阶段复成因”特点,经历了3个主要成矿期,即古元古代同生沉积就位成矿期、吕梁变质-变形“重就位”成矿期和中生代构造-岩浆活化“再就位”成矿期.矿床成因属以海底（喷流）热水沉积作用为基础,遭受后期变质变形和热液叠加的广义层控性矿床,即属海底喷气沉积变质-岩浆热液改造型铅锌矿床.     

华北地块北缘中段铅锌银矿床成矿作用讨论

华北地块北缘中段分布着许多大中型铅锌银矿床，依据其成因特征可划分为四种类型：沉积喷气型矿床、叠加改造型矿床、与大红峪期碱性火山活动有关的浅成低温热液矿床、与中生代火山－斑岩活动有关的热液矿床。成矿作用具多期多成因的特点：古元古代火山沉积作用不仅可能形成了区内最早的VMS型矿床，而且成为区内最重要的矿源层；中元古代早期形成了本区最古老的浅成热液银多金属矿床；中元古代中期形成了又一期VMS型矿床；而中生代是本区铅锌银最重要的成矿期，成矿显然受基底的制约。     

华北地块北缘中段铅锌银矿床成矿作用讨论

华北地块北缘中段分布着许多大中型铅锌银矿床,依据其成因特征可划分为四种类型:沉积喷气型矿床、叠加改造型矿床、与大红峪期碱性火山活动有关的浅成低温热液矿床、与中生代火山-斑岩活动有关的热液矿床.成矿作用具多期多成因的特点:古元古代火山沉积作用不仅可能形成了区内最早的VMS型矿床,而且成为区内最重要的矿源层;中元古代早期形成了本区最古老的浅成热液银多金属矿床;中元古代中期形成了又一期VMS型矿床;而中生代是本区铅锌银最重要的成矿期,成矿显然受基底的制约.     

2801铜铀金矿化特征及其地质找矿意义

２８０１铜铀金矿化点位于康滇地轴南段。受ＳＮ向罗茨－易门断裂和元谋绿汁江断裂所控制。矿化产于旁侧的次级断裂交叉部位。含矿断裂为因民组与美党组之间的不整合面层间构造断裂破碎带。近矿围岩为含碳千枚岩，赋矿岩石为构造角砾岩。矿石矿物成分复杂，有沥青铀矿、黄铜矿、黄铁矿、辉钼矿等，近矿围岩蚀变发育，主要有钠长石化、白云石化、硅化、硫化物化、水云母化、赤铁矿化等。成矿时代为７２９Ｍａ，成矿温度Ｔ／Ｋ为５７３．１５～６７３．１５，属沉积变质－热液改造型矿化，具有不整合脉型和碱交代型双重特征。     

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。     

On the consistency of proposed models for the Pyrenees with the structure of the eastern parts of the belt

The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time.     

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.