不同航磁数据处理方法的地质应用效果分析:以云南宣威—贵州赫章地区为例

目前,利用航磁数据圈定磁性地质体边界的方法主要有航磁ΔT化极法、航磁ΔT化极垂向一阶导数法、总梯度模法和斜导数法等4种。云南宣威-贵州赫章地区火山岩分布面积广泛,下二叠统峨眉山玄武岩具有强磁性,而其他地层岩石磁性很低;为了圈定研究区内磁性地质体的目的,利用该区1∶5万航磁测量数据,阐述了ΔT化极法、化极垂向一阶导数法、斜导数法和总梯度模法等4种数据处理方法的地质应用效果,认为应根据有效磁化方向与地磁场方向是否一致来选用不同的航磁数据处理方法,以达到有效圈定地质的目的。     

460矿床关键控矿要素重磁异常特征及深部结构研究

通过在460矿床开展重、磁勘探工作,研究了控矿要素的重、磁异常特征,分析了主要断裂构造、火山机构、主要岩体的分布情况;利用重磁联合二维正反演、密度界面反演推断了研究区基底界面深度;利用地表地质条件作为约束三维密度反演推断了研究区3大地层的空间分布。研究表明,重磁勘探在火山岩地区确定盆地范围、识别断裂构造效果明显,矿床位置一般位于重磁高场向低场的过渡区域,重磁梯度带是寻找铀矿的重要标志。     

航空重磁在山东齐河厚覆盖区圈定隐伏岩体的方法及效果

山东齐河地区被大面积巨厚的新生代地层覆盖,但富铁矿资源潜力大,隐伏岩体的圈定对于提高厚覆盖区基础地质研究程度和矿产勘查具有重要意义.通过航空重磁数据处理提高解释的准确性,利用航磁△T化极垂向一阶导数、归一化总水平导数垂向导数、航空重力剩余异常等实现隐伏岩体范围圈定,在研究区共圈定6处中基性岩体,并利用航磁切线法、航空重...     

利用重、磁资料研究于都—赣县矿集区盘古山地区断裂构造及花岗岩体分布

盘古山地区是于都—赣县矿集区内一个重要的钨锡矿成矿区,研究区断裂构造和花岗岩体与成矿关系密切。利用重、磁资料研究盘古山地区断裂构造及花岗岩体分布,为深部找矿提供地球物理依据。利用重力异常归一化总水平导数垂向导数技术推断断裂构造平面位置;利用欧拉反褶积方法对重力异常垂向一阶导数进行反演计算,推断断裂构造平均深度;利用重磁异常垂向一阶导数技术推断花岗岩体平面位置;利用RGIS软件2.5D重磁剖面人机交互正反演技术推断花岗岩体断面位置,并用钻孔验证解释结果的正确性;利用RGIS软件3D重磁模型编辑模块展示花岗岩体空间位置。研究结果显示盘古山地区既有出露断裂,又有隐伏断裂,既有出露低密度、弱磁性花岗岩体,又有隐伏低密度、强磁性花岗岩体,花岗岩体分布受断裂构造控制,矿体分布受断裂构造和花岗岩体共同控制。     

广东丰顺-大埔地区1∶5万区域地质矿产调查成果与主要进展

在广东丰顺-大埔地区完成的1∶5万区域地质矿产调查,对区内地层进行了多重地层划分和对比研究,理清了地层层序;采用火山岩性岩相-火山构造-岩石地层三重填图法,查明了火山岩性岩相、火山机构分布特征,划分了火山活动旋回;按"岩性+时代"的表达方式对侵入体进行填图单元的划分,解体了复式岩体,研究了侵入岩地球化学特征,探讨了成岩时代;对区内构造形迹进行调查研究,查明了区内褶皱构造和脆性断裂的变形特征,识别出梅县地区晚中生代伸展构造体系;获取大量的同位素年龄值,精确的厘定了地质体形成和地质事件发生的时间;通过综合研究,圈定了成矿靶区和找矿远景区,归纳了成矿规律。     

甘肃白银厂铜多金属矿田重磁异常及构造特征北大核心CSCD

甘肃白银厂铜多金属硫化物矿田是受陆缘弧环境火山机构及其同生断裂控制的典型火山岩赋矿块状硫化物矿床(VHMS)。为了进一步探讨该矿床重磁场特征及与构造和矿床的关系,通过对区内的重磁场异常数据进行位场分离、小波分析和基于张量数据的三维欧拉反褶积自动确定地质体位置和埋藏深度的定量反演计算。结果表明,研究区布格重力场具有西部高、东部低的特征,其磁场可划分为4个磁场区;局部异常按一定分布规律呈圆形或似圆形正负相间分布,不同尺度的重磁细节异常图在一定程度上反映出引起重磁异常的地质异常体具有一定的延深且分布稳定,而且这些地质异常体具有向深部复合的趋势。经位场分离后正负相间的剩余重磁异常分布范围和分布特征大致反映了白银厂奥陶纪中酸性火山岩建造构造为一个继承性的火山穹窿构造,东、西部不同的重磁异常特征说明东西部的火山喷发具有不同的基底、源区和喷发方式。发育NW向、NE向、近NS向、NEE向等4组断裂构造,近NS向断裂F3、F4、F5、F6、F7形成时间稍晚于NEE向断裂,其与NEE向断裂F1、F2共同形成了研究区棋盘网格状的构造分布特征,这两组断裂为研究区内主要的控岩、控矿断裂。火山机构的分布明显受断裂构造控制,火山口集中分布在深大断裂、大断裂或两组断裂的交汇处。矿田内各矿床及成矿有利地段均处于研究区中部低缓重磁异常场内正负磁异常变化的梯度带内。本次研究为控矿要素研究和开展找矿预测工作提供了丰富、翔实的地球物理资料。     

高精度磁测技术在西成铅锌矿勘探中的应用

近年来,甘肃西成铅锌矿的勘探向周边地区扩展,高精度磁法测量发挥了一定作用。利用化极磁异常垂向一阶导数和归一化总水平导数垂向导数,推断出5处地质体边界和4条断裂。根据该区地质和矿产分布特征,推测矿体主要分布于黑云母石英片岩向大理岩的接触或过渡地带,对应中泥盆统安家岔组厂坝层D2a1条带状大理岩。根据化极磁异常和该区构造,结合化探圈定出与成矿有关的4个靶区,这些靶区与Pb、Zn化探异常对应,可见若干矿化点。选取靶区内一磁测剖面进行反演,反演结果说明矿体向北西倾斜。经钻孔验证,已在不同深度见矿,证明了靶区的找矿潜力。     

重磁方法在吐尔库班套铜镍矿区勘查中的应用

利用实测的重、磁资料和岩石物性资料,并结合矿区地质、钻孔等资料,确定了重高、磁高为吐尔库班套铜镍矿区内识别超基性和基性岩体的标志,重磁对应分析结果表明研究区重磁异常具有很好的同源性。利用归一化总水平导数垂向导数(NVDR_THDR)技术推断了5条断裂,研究认为北西向断裂形成较早,其与研究区主体构造走向一致,北东向断裂形成较晚并将北西向断裂错断。利用布格重力异常垂向二阶导数、化极磁力异常垂向一阶导数以及重磁对应分析结果推断了18个基性、超基性岩体并研究了其规模及平面分布特征,利用重磁联合人机交互反演技术解释了基性、超基性岩体的纵向分布特征和规模,结果表明研究区基性、超基性岩体规模不大。综合研究了断裂分布特征以及岩体分布特征,认为研究区基性、超基性岩体的分布明显受断裂控制,而且主要分布在F1、F4和F5断裂组成的区域,并具有明显的分带性,其与北西西向的断裂分布是一致的,推测岩体主要沿着北西西向断裂侵入,北东向断裂对岩体的分布起到限制作用。     

利用不同深度场源磁异常分离的方法解译隐伏岩体

为了查明安徽省殷家汇地区隐伏岩体的赋存状况,初步圈定侵入性中酸性岩体的范围并推测有利赋矿位置,对地面实测磁异常进行化极、延拓、不同深度场源磁异常分离、垂向导数等数据处理,提取利于识别的剩余磁异常及垂向一阶导数磁异常,结合地质资料解译磁异常特征。结果表明: 区内NE向剩余磁异常带为沿断裂构造侵入的脉岩引起,NE向构造为区内主要的控岩和控矿构造; 推测引起局部剩余磁异常的磁性地质体为隐伏或半隐伏中酸性岩体。该研究为长江中下游铁铜金成矿带中的安庆—盱眙地质矿产调查区成矿远景区划分及找矿靶区初选提供参考。     

道朗和都格地区重磁场特征与找矿远景区

道朗和都格地区为华北板块北缘的一个多金属成矿区,为了预测研究区多金属矿产的分布情况,利用位场数据处理中的向上延拓、对垂向一阶导数的小子域滤波和重磁对应分析等方法,对该区1∶5 000重磁资料进行了处理。综合分析了研究区重力场、磁力场、重力剩余场、重力垂向一阶导数、重磁对应分析中相关系数的基本特征及其与岩矿石密度和磁化率的分布关系。结合研究区地质资料及钻井资料,划分出5条断裂,圈定了11处金属找矿远景区,并综合分析了断裂划分及找矿远景区圈定的依据。     

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″.     

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 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.     

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.