胶东金矿田的深部地球物理勘查模式初步研究

胶东金矿田深部"第二富集带"找矿潜力巨大,但预测难度也大,其中一个问题是深部勘查目标难以识别。作为复杂成矿过程的产物,按经济指标划分的金矿体和规模更大的构造蚀变带,可以整体上作为深部地球物理勘查的目标,扩大目标地质体的规模,从而提高物探方法的分辨率。基于矿床地质特征、岩（矿）石物性参数及含矿构造岩相带的空间形态特点,将胶东地区金矿床分为三类：一维角砾岩型、二维蚀变岩型、二维石英脉型。依托"中生代岩浆核杂岩隆起—拆离带"控矿构造模式,应用含矿构造岩相带和地球物理方法相结合的工作模式,在玲珑—焦家、大庄子、蓬家夼等矿田开展深部找矿预测,为物探方法有效识别深部矿化带提供理论和技术支持。     

胶东玲珑金矿田构造蚀变岩测量与成矿预测

对几十年来地质找矿工作进行总结,支撑深部找矿的重大难题,经过多年的实际观测和分析研究,完成了“山东省招远市玲珑金矿构造蚀变成矿图”。玲珑金矿田发育玲珑焦家式金矿--陆内岩浆期后热液蚀变剪切带硫化物石英脉黄铁绢英岩蚀变破碎岩型金矿。该类矿床受断裂破碎带影响,成矿地质体是黄铁绢英岩质蚀变岩带。研究应用构造蚀变岩的地质测量和研究方法,实测了大量的构造岩相剖面,开展了1∶2 000和1∶10 000的填图。结果显示：(1)矿田处于滦家河岩体外接触带,赋矿围岩主要是玲珑似片麻状黑云母花岗岩。花岗岩的似片麻理走向显示北西西至南东东向分布,带有胶东基底的构造痕迹。(2)断裂蚀变矿化带控制了金矿的分布规律,它们受到后期构造的改造。(3)图中从西到东、从北到南,流体交代蚀变岩的规模都逐渐增大,因此,通过断裂蚀变岩的发育情况,可知较大矿床集中在矿田的东南部。东南部构造及蚀变带规模大,矿体埋藏深,有良好的成矿远景。“山东省招远市玲珑金矿构造蚀变成矿图”的编制,反映了区内控矿构造的新资料。关于矿田找矿预测的靶区得到了探矿工程的验证,并有力地支持了今后一个阶段的深部找矿问题。以成矿地质事件为基础的大比例尺构造岩相地质填图及找矿方法,具有重要的成矿研究和深部外围找矿意义,值得进一步深化和推广。     

胶东矿集区金成矿系统组成与演化概论

由于中生代以来构造动力体制多次转换及火山-侵入岩活动形成了胶东矿集区金成矿系统。成矿类型主要以石英脉型、复合脉带型、浸染细脉带型等类型为主，多种类型金矿多为同源成矿溶液在不同构造背景和物化条件下的沉淀产物，从而发育类似的构造-蚀变-矿化分带结构。胶东矿集区存在3期成矿作用，金成矿作用主期明显集中于燕山中期（130~120 Ma），（含金）银矿化为燕山晚期（<97 Ma），含金（银）铅锌矿化介于两者之间、更接近于燕山晚期（100 Ma前后），区域地质事件的定年与因果分析显示这三期成矿过程的物质来源、成矿作用均受壳-幔相互作用等大尺度构造体制转折事件控制。     

山东焦家金矿带深部找矿的重大突破及其意义

通过5年时间对山东焦家金矿带深部的地质找矿工作,发现了位于莱州寺庄矿区深部的特大型破碎带蚀变岩型金矿.该矿床与产于焦家断裂第一矿化富集带中的寺庄矿区浅部金矿床之间有100～250m垂深的无矿间隔,构成第二矿化富集带.认为胶西北地区3务主要金矿控矿断裂--三仓断裂、焦家断裂、招平断裂具有明显的相似性,形成上陡下缓的铲状断层,构成了沿玲珑花岗岩与早前寒武纪地质体边界分布的大型伸展构造带.建立了焦家式金矿新的成矿模式:在伸展构造主断面附近的岩石受到强烈的伸展剪切应力,产生倾向与伸展滑动方向一致的一系列伸展断层,构造岩为变形均匀的碎粒岩和糜棱岩,形成浸染状蚀变岩型矿石;主断面之下,由伸展引起的剪切应力,产生了具共轭剪节理性质的网状裂隙带,形成网脉状矿石;远离主断面,岩体上拱造成的引张作用产生近直立的裂隙带,形成脉状矿石.指出焦家金矿带深部成矿远景区在该断裂平面位置的西侧,而非其东侧的玲珑花岗岩分布区.     

胶东金矿成矿深度的构造校正测算及成矿预测

成矿深度测算对于矿床学理论研究和深部找矿都有重要意义。经典的成矿深度“压力/比重”计算方法,缺乏考虑构造应力在成矿过程中的影响。前人按照“压力/比重”的计算方法,提出胶东蚀变岩金矿是6 000~8 000 m深的元古宙成矿,石英脉型金矿是深度在3 000 m左右的中生代成矿,并据此建立了金矿垂直五层楼的分带模式。依据该模式指导的深部预测勘查效果不好。“成矿深度构造校正测算”是近几十年逐渐成长起来的一个新方法,即先减去“构造附加压力”后再进行成矿深度测算。本文介绍“成矿深度构造校正测算”的计算方法,指出其应用条件和预测意义。开展成矿深度构造校正测算需要以下条件:(1)确定成矿模式;(2)开展野外构造变形岩相测量;(3)测量岩石矿物应变,恢复成矿构造应力场,计算构造附加静水压力;(4)测算成矿深度。根据“成矿深度构造校正测算”方法已经获得胶东多个典型金矿成矿深度的测算结果:(1)夏甸金矿成矿深度为-1 979.51~-3 014.72 m;(2)焦家金矿成矿深度为-1 632.4~-2 331.6 m;(3)大尹格庄金矿成矿深度为-2 775.4~-4 164.5 m;(4)新城金矿成矿深度为-1 781.29~-2 750.0 m;(5)玲珑金矿成矿深度为-720.55~-3 454.97 m。根据以上典型金矿成矿深度的测算结果,本文认为胶东金矿属于深-1 000~-4 500 m的浅成热液剪切带型矿床,由此推断胶东典型金矿矿体主要部分仍然赋存在深部。按照“构造校正测算”方法得到的成矿深度,结合地质、物探和化探信息,预测金矿发育“深部第二富集带”,已经得到胶东金矿勘查工作的证实。     

胶东玲珑金矿田构造蚀变岩测量与成矿预测

<正>玲珑金矿田发育玲珑-焦家式金矿——陆内岩浆期后热液蚀变剪切带硫化物石英脉-黄铁绢英岩蚀变破碎岩型金矿(吕古贤,1993;1997)。该类矿床受断裂破碎带影响,成矿地质体是黄铁绢英岩质蚀变岩带。本文通过实测填制"胶东玲珑金矿田构造蚀变岩相分布图(1∶10000)",把矿田玲珑-焦家式金矿中生代岩浆期后热液破碎带蚀变成矿的事件用地质图的形式加以表达,并首次展示了玲珑矿田断裂蚀变岩的分布形态及其成矿规律(申玉科,2003;路彦明,1999)。大比例尺构造蚀变岩相填图对研     

胶东玲珑金矿田171号脉深部金矿床特征及构造控矿作用

玲珑金矿田171号脉赋存于招平断裂北段破头青断裂中,在其深部探明金资源储量150余吨,确定其为超大型破碎带蚀变岩型金矿床。为了揭示构造与成矿、深部矿与浅部矿、石英脉型矿与蚀变岩型矿等的关系,为深部找矿提供典型实例和理论依据,文章通过大量矿区地质勘探、野外地质调查和区域地质综合研究,剖析了矿床特征,揭示了构造控矿规律。171号金矿脉深部共有7个金矿体,均为盲矿体。其中,171_1号主矿体埋深120~1700m,呈似层状、大脉状分布,沿走向及倾向显舒缓波状。矿体总体走向60°,倾向SE,倾角36.5~43.5°。矿体长2500m,斜深510~3100 m,平均厚度4.23 m,平均金品位2.71×10~(-6),矿石主要为黄铁绢英岩型(蚀变岩型)。矿脉和矿体受断裂构造控制,矿化、构造、蚀变分带具有一致性。由控矿断裂的主裂面至远离主裂面,构造变形强度由强变弱,蚀变强度和矿化强度也由强变弱。招平断裂是一条切割早期韧性剪切带的脆性断裂,总体呈舒缓波状展布,大部分地段发育于早前寒武纪变质岩系与侏罗纪玲珑型花岗岩之间,断裂上盘脆性变形较弱,下盘脆性变形带宽大,是沿不同时代地质体之间发育的左行铲式正断层,类似于拆离断层,是胶东白垩纪伸展构造的组成部分。玲珑金矿田是典型的石英脉型金矿产地,但大型金矿床多为赋存于断裂构造中的蚀变岩型金矿床,石英脉型金矿床与蚀变岩型金矿床是同一构造系统中不同构造位置的产物;一般在主断裂中赋存蚀变岩型金矿床,在主断裂下盘的次级张裂隙中产出石英脉型金矿床。胶东以正断层为主的伸展构造系统为大规模成矿提供了有利条件,构造、蚀变分带和不同类型金矿床的关系是金矿找矿的重要标志。     

胶东区域成矿断裂带蚀变年龄研究及其矿床学意义

胶东金矿是中生代构造岩浆活化区岩浆期后中温热液蚀变脉状矿床。前人曾认为该类金矿属于壳源深融花岗岩-热液石英脉-蚀变岩型金矿。近期研究表明,胶东金矿围岩蚀变年龄的测定,对于矿床成因的研究有重要意义。为解决胶东区域断裂热液蚀变年龄问题,对胶东半岛主要断裂矿化蚀变带开展如下相关研究:(1)选择胶东地区各蚀变岩带普遍发育的黄铁绢英岩化蚀变岩带和强钾长石化蚀变岩带作为取样目标,进行区域对比;(2)该两类岩石中的蚀变矿物受到脆性断裂影响较小,能够得到蚀变阶段的稳定化学成分;(3)该两类岩石中的蚀变矿物发育有与蚀变同期的韧性变形,能够揭示蚀变阶段的构造应力应变状态。对样品中的钾长石和斜长石颗粒进行K-Ar法同位素年龄测试,获得蚀变岩同位素年龄数据。测试结果显示,胶东区域构造热液蚀变作用时期为(148.3±4.3)~(52.03±0.70)Ma,即早白垩世燕山晚期;同位素年龄自西向东逐渐变小,证明胶东西部地区的热液蚀变作用早于东部地区。通过分析已有的构造、热液成分和成矿物理化学参数等资料,结合本研究的最新成果,总结出区域成矿时代与成矿规律:胶东区域断裂蚀变系统中的构造附加静水压力、流体温度压力条件和成矿元素的分布与变化控制了热液蚀变成矿规律。上述地质特征显示,胶东金矿床是复成构造热液作用下的一种新型矿床类型。     

胶东三山岛断裂构造蚀变岩三维控矿规律研究与海域超大型金矿的发现

三山岛北部海域金矿床位于胶东西北部三山岛成矿带之内,为一严格受断裂构造控制的超大型破碎带蚀变岩型金矿床。该次找矿预测并获重大突破的预测依据如下：(1)三山岛断裂蚀变矿化带,受NNE和NEE两组方向的区域构造控制,复合叠加呈“N”字形分布。陆上断裂蚀变矿化带接近海域,并没有间断,推测在三山岛北部延伸至海区。(2)焦家和三山岛两断裂蚀变矿化带,具有统一的三维控岩控矿规律。焦家断裂蚀变金矿带向西倾斜,控矿构造和矿化富集程度显示阶梯状分布,其中矿体向南西侧伏,矿体在剖面上呈左行右列式分布;而三山岛断裂蚀变金矿带向东倾斜,其中矿体向NE侧伏,矿体在剖面上呈右行左列式分布。依据陆内构造控岩控矿规律预测海域未知矿体的分布规律,获得了良好的验证。(3)三山岛金矿到焦家金矿的勘探剖面显示,两个控矿构造岩相带倾向相反,但是都在下盘花岗岩区段集中交代蚀变成矿。这一认识为确定深部成矿靶区提供了准确的地质依据。(4)地球物理勘查结果显示,三山岛矿带的重力和磁力异常指出沿“N”字形构造从陆地向海区延伸,这成为预测的重要依据。总之,三山岛北部海域金矿床目前业已取得找矿重大突破。矿床为焦家式破碎蚀变岩型金矿,属中生代燕山晚期岩浆热液脉型矿床,其深部及外围仍具有良好的找矿前景。     

玲珑金矿田深部断裂蚀变岩相分带特征研究

玲珑金矿田位于招远市城北20km玲珑镇,区内所见地层为新生界第四系山前组（Qs）、胶东岩群苗家岩组（ArjM）和胶东岩群郭格庄岩组（Ar3jG）。矿体多赋存于玲珑花岗岩中。矿体矿化严格受断裂构造和交代蚀变岩带控制,以 NE、NEE和NNE走向的三组断裂最发育,倾向NW或SE。倾角40°～80°南东倾斜的欧家夼一带为NEE向矿化蚀变带;东山大开头矿段及至玲南矿段发育NE方向矿化蚀变带;而九曲蒋家延至东风阜山矿段均呈NNE向矿化蚀变带;它们组成了矿田基本地质构造框架。     

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.