辽西凌源地区义县组火山岩锆石U—Pb年代学和地球化学特征

对辽西凌源地区义县组的1件流纹岩样品进行锆石U—Pb年代学研究,获得的年龄为（124．4±1．4）Ma,与前人对辽西北票、义县、凌源等地区通过K—Ar、Ar—Ar、U—Pb等定年方法获得的义县组年龄基本一致,时代为早白垩世。7件典型火山岩样品的地球化学研究结果表明,该火山岩的SiO2=65．6％-73．4％,MgO=0．35％～1．23％,Mg^#=16～41,Al2O3=13．40％～16．79％,Na2O=3．54％-4．26％。Sr=（445～774）×10^-6,Yb=（0．51-0．97）×10^-6,V=（7～14）×10^-6,Sr／Y=49-66,LaN／YbN=33-48,高Sr和Sr／Y比值,低Y和Yb,轻重稀土元素分异明显,显示出埃达克岩的地球化学特征,但其Mg^#较低。它们可能是加厚的基性下地壳部分熔融的产物。     

辽西彰武大四家子地区中生代火山岩锆石U-Pb年代学及地球化学特征

通过对辽西彰武县以东大四家子乡高城窝堡村义县组标准剖面中生代火山岩锆石U-Pb年代学研究表明, 其火山岩年龄为122.4±0.4Ma, 属早白垩世.对该区域23件典型火山岩样品的地球化学研究表明, 除3件流纹岩样品外, 其余样品具有高镁埃达克岩地球化学特征(SiO₂=56.46%~65.14%、Al₂O₃=14.60%~17.19%、Mg#=50~59、Sr=501~700μg/g、Yb=1.04~1.54μg/g、Y=12.0~17.5μg/g、Eu/Eu*=0.85~0.97、Sr/Y=29~46、La_N/Yb_N=13~28), 同位素上具有高的初始87Sr/86Sr(0.705464~0.705812)比值, 低的ε_Nd(122Ma)(-6.12~-12.80)值特征, 同时样品中存在具有反环带的辉石斑晶, 辉石中稀土元素含量分布存在着从核部到边部逐渐降低的趋势, 且存在负铕异常(Eu/Eu*=0.64~0.76).结合前人对彰武义县组下部火山岩的研究, 笔者倾向认为该套火山岩的成因是拆沉作用与岩浆混合作用共同作用的结果, 即拆沉作用导致软流圈地幔物质上涌加热下地壳形成的长英质岩浆, 与来自地幔由拆沉作用形成的埃达克质高镁安山岩浆混合形成.      

辽西地区早中生代火山岩地球化学特征及成因探讨

辽西地区早中生代火山岩的岩石共生组合为粗安岩-安山岩-英安岩-粗面英安岩,属于高钾钙碱性-钙碱性火山岩系.岩石总体上反映出高Al、高Na特点,SiO2≥56.99%,Al2O3≥15.16%,Na2O/K2O≥1.13.其地球化学的显著特点是稀土元素分馏明显(La/Yb≥14.89,Yb≤1.90×10-6);基本无Eu负异常(0.78～0.97);Y值较低(≤1 7.51×10-6);明显亏损Rb,Th,Nb,P,Zr和Ti,而富集Ba,K,Sr及REE,不同于正常岛弧钙碱性火山岩;火山岩的Rb/Sr≤0.15,Sr/Y≥35.1 6,属于高Sr低Yb、低Y岩石.火山岩地球化学研究表明,早中生代火山岩与埃达克岩十分类似,属埃达克质岩.铅、锶和钕同位素资料反映出火山岩的源岩较深,可能为古老的下地壳中-基性变质岩部分熔融产物.辽西地区早中生代火山岩形成于华北板块与西伯利亚板块碰撞-超碰撞的陆内挤压环境,与太平洋板块俯冲没有直接关系,而与加厚地壳导致的下地壳拆沉作用密切相关.辽西地区早中生代埃达克质岩的确认对探讨辽西地区火山岩浆起源、壳幔相互作用及大陆动力学背景具有重要意义.     

大兴安岭中段突泉盆地高Mg#火山岩激光全熔~(40)Ar/~(39)Ar测年与地球化学特征

对大兴安岭中段突泉盆地中出露的高Mg#火山岩进行了详细的岩石学、激光全熔40Ar/39Ar测年及地球化学研究,讨论了该组火山岩成因、岩石物质来源及其地质意义.突泉盆地高Mg#火山岩为一套中酸性岩石,化学成分显示其主要为安山岩与英安岩.岩石激光全熔40Ar/39Ar测年结果显示火山岩年龄为136.0±2.0 Ma,形成于早白垩世早期.火山岩地球化学特征总体表现出了埃达克质岩石的地球化学特征:SiO2≥57.50%,A12O3≥16.66%,MgO<3.31%,Mg#>45,贫Y(平均值17.53×10-6),贫Yb(平均值1.84×10-6),高S(r>534×10-6),高Ba(789×10-6⁹25×10-6);Sr/Y=22.71925×10-6);Sr/Y=22.71⁷3.54,Y/Yb=8.9573.54,Y/Yb=8.95¹1.32;REE分异明显,富集LREE,亏损HREE;无明显Eu异常(平均Eu/Eu*=0.94).该套高Mg#火山岩可能是加厚基性下地壳发生部分熔融并与底侵的基性岩浆混合的产物.结合大兴安岭中生代盆岭构造演化的特点,突泉盆地早白垩世高Mg#的埃达克质火山岩形成于蒙古-鄂霍茨克洋(古太平洋)闭合造山阶段碰撞构造背景,岩浆源区性质主要归因于增厚的造山带下地壳部分熔融作用.     

辽西凌源地区张家口组的重新厘定及其意义——来自激光ICP—MS锆石U—Pb年龄的制约

辽西凌源地区张家口组是否存在及其与义县组之间关系的问题一直存在争议。笔者研究表明，凌源地区不仅存在张家口组，而且其与义县组之间为角度不整合接触，它们是不同构造层的产物；义县组的底部层位即为大王杖子层(尖山沟层)。激光ICPMS锆石U-Pb测年得出该地区张家口组火山岩顸界年龄为132．4-130．2Ma，前人得出该地区义县组底部层住(即大王杖子层)的形成时代为126-123Ma，反映该地区张家口组顸部与义县组底界之间存在约6Ma的时间间隔。此时间间隔内研究区不仅发生了构造格架的转换，也是辽西北票一义县地区幔源高镁火山岩的主体喷发期，中国东部中生代岩浆作用也在此时期达到高潮，翼北-辽西地区该时期之后发生了热河生物群大爆发，说明该时期也是一个重要的生物界限。     

辽西中侏罗统海房沟组火山岩的地球化学特征

辽西中侏罗世海房沟组火山岩是燕山造山带中生代火山岩的重要组成部分.海房沟组火山岩主要由粗安岩组成, 其次为英安岩和安山岩, 属于准铝质岩石和高钾钙碱性火山岩系列岩石.地球化学资料表明, 辽西中侏罗世海房沟组火山岩具有低镁埃达克质火山岩的特征, 如SiO₂≥51.98%, Al₂O₃≥15.0%, MgO＜4.18%(Mg#＜0.48), Sr≥436×10-6, Yb≤2.25×10-6, Y≤23.14×10-6, Cr≤81.09×10-6, Ni≤34.66×10-6, Y/Yb≤14.25, Sr/Y≥39和Nb/Ta≈20;轻稀土元素富集, Ba、U、Sr和Pb等相对富集, 而重稀土元素和高场强元素(如Nb、Ta、Ti)相对亏损, 轻重稀土元素强烈分馏((La/Yb)_N≥10.37), 具有弱的负铕异常或正异常(0.79~1.05).另外, Nd、Sr同位素具有较低的(143Nd/144Nd)初始值(0.511 603~0.511 733, ε_Nd(t)=-15.84~-13.30)、适中的87Sr/86Sr初始值(0.704 9~0.705 6, ε_Sr(t)=8.64~18.11)和较高的亏损地幔模式年龄(T_DM=1.81~1.99 Ga), 显示出富集地幔端员(EMI, Enriched Mantle End-member)特点.上述特征表明, 海房沟组埃达克质岩浆起源于较厚下地壳榴辉岩部分融熔, 其成因与玄武质岩浆的底侵作用有关.结合中生代火山岩的地球化学及其成因, 认为早-中侏罗世是燕山造山带从古亚洲洋构造体系向古太平洋构造体系的转折时期, 而中侏罗世海房沟组火山岩的形成(174 Ma)标志着燕山造山带进入了古太平洋构造体系的演化阶段.这对进一步理解燕山运动的深部过程及其岩石圈减薄提供重要信息.      

辽西中侏罗世高Sr低Y型火L山岩的成因及其地质意义

通过对辽西阜新地区中体罗世蓝旗组火山岩的岩石地球化学研究,燕山地区存在着中侏罗世高Sr低Y型火山岩.这些高Sr低Y型火山岩为高铝高钠低镁(A12O3＞15%,Na2O≥3.37%,MgO≤1.33%,Mg#≤0.35)的安山岩-英安岩,高Sr(≥541μg/g)低Y、Yb(Y≤19μg/g,Yb≤1.35μg/g)含量及高Sr/Y(≥40)比值,强烈的稀土元素分馏((La/Yb)N＞17,(Ho/Yb)N＞1.2)),Eu异常不明显(0.82～0.96),高场强元素(如Nb、Ta)相对亏损.这些特征与太古代英云闪长岩-奥长花岗岩-花岗闪长岩(TTG)岩套相似.我们认为这些火山岩起源于古老的下地壳玄武质岩石的部分熔融,其形成可能与玄武质岩浆的底侵作用有关.辽西中侏罗世蓝旗组高Sr低Y型火山岩对探讨燕山造山带岩浆起源及地球动力学具有重要意义.     

辽西地区中侏罗世海房沟组火山岩地球化学特征及其地质意义

辽西地区中侏罗世海房沟组火山岩的岩石共生组合为粗安岩粗面岩安山岩英安岩 ,属于高钾钙碱性钙碱性火山岩系 ,全岩Rb_Sr等时线年龄为 177.2± 2 8.0Ma。岩石总体上反映出高Al高Na特点 ,SiO2 ≥ 5 6 .99% ,Al2 O3 ≥ 15 .4 5 % ,Na2 O/K2 O≥ 1.35。稀土元素分馏明显 ,(La/Yb) N≥ 14 .80 ,(Ho/Yb) N≥ 1.15 ,贫Yb、Y(Yb≤ 1.4 2× 10 -6,Y≤ 15 .18× 10 -6) ,基本无Eu负异常 (0 .86～ 1.0 3) ,明显亏损Rb、Nb、Zr、Ti,而Sr、Ba、K及LREE富集 ,Rb/Sr值均小于 0 .1,地球化学特征与埃达克岩十分类似 ,属埃达克质岩。Sr、Pb和Nd同位素资料反映出这套火山岩的源岩较深 ,可能为古老的下地壳中基性变质岩部分熔融产物。研究表明 :海房沟组火山岩形成于板内环境 ,与太平洋板块俯冲没有直接关系 ;辽西地区中生代构造应力场的重大转换、广泛的岩浆活动和大规模断陷盆地群的形成与岩石圈拆沉作用密切相关。海房沟组埃达克质岩的确认对探讨辽西地区火山岩浆起源、壳幔相互作用及大陆动力学背景具有重要意义。     

青藏高原北部查保马组火山岩的锆石SHRIMP U-Pb定年和地球化学特点及其成因意义

查保马组火山岩位于青藏高原北缘、可可西里东部,为一钾质C型埃达克岩,形成于新近纪中新世(N_1)时期,锆石SHRIMP U-Pb谐和年龄为13.2±0.6～18.3±1.1Ma。火山岩具有SiO_2为59.48%～64.63%,富碱(Na_2O k_2O=7.52%～8.30%),高K_2O(4.21%～4.62%),高MgO(0.76%～2.48%)和高Mg~#值(0.26～0.51),以及钾玄岩系列的岩石地球化学特征。稀土总量非常高(∑REE=482.26×10~(-6)～592.11×10~(-6)),轻稀土强烈富集(LREE=466.47×10~(-6)～571.69×10~(-6)),重稀土显著亏损(HREE=14.00×10~(-6)～20.43×10~(-6)),Y含量(13.29×10~(-6)～19.87×10~(-6),平均16.27×10~(-6))和Yb含量(1.11×10~(-6)～1.66×10~(-6),平均1.37×10~(-6))普遍偏低。稀土元素配分模式呈轻稀土强烈富集的右倾斜型,(La/Yb)_N值为61.02～91.67。负铕异常不明显(Eu/Eu*=0.74～0.86)。Sr含量及Sr/Y比值高,分别为949×10~(-6)～1497×10~(-6)和54～108,微量元素比值蛛网图上强烈地表现出Nb、Ta、P、Ti、Y的负异常。查保马组(N_1c)钾质C型埃达克岩是青藏高原北部在中新世时期因大陆地壳巨量增厚(75～80km)引起榴辉岩相的下地壳物质发生部分熔融的岩浆产物。     

青龙-建昌地区中生代火山岩地球化学特征及岩石成因

青龙-建昌地区的中生代火山岩地层主要有髫髻山组(兰旗组)和义县组。髫髻山组粗安岩富碱高钠、低镁含量;稀土元素总量不高[∑REE=(110.93~169.79)×10~(-6)],轻重稀土分馏明显[(La_N/Yb_N)=13.52~24.46],具有弱的负铕异常或正异常(δEu=0.96~1.15);富集大离子亲石元素Ba、K、Sr,亏损高场强元素Nb、Ta、P、Ti;高Sr含量[(682~1065)×10~(-6)]和Sr/Y值(49~74),低Y[(9.1~17.9)×10~(-6)]和Yb含量[(0.79~1.74)×10~(-6)],显示为埃达克岩的地球化学特征。义县组粗安玢岩与髫髻山组粗安岩具有相似的稀土和微量元素特征,但低Sr、高Y和Yb含量,为非埃达克质岩石。义县组酸性火山岩高硅富碱、低钙铁镁含量;强烈亏损Sr、P、Eu,为斜长石和磷灰石结晶分异的结果。通过与邻区(沽源-红山子)张家口组产铀火山岩的岩石组合、地球化学等特征进行对比分析,认为研究区具有良好的铀成矿前景。     

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 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.     

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。     

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.     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。      

塘口水电站坝基岩体透水性和渗漏问题分析

塘口水电站大坝基础座落在断层和裂隙较发育的龟裂纹灰岩上,岩体完整性差、透水性强,多年运行后,大坝灌浆廊道和排水廊道出现多处集中性漏水,为确保大坝安全和电站正常发电,根据渗漏性质和成因,采用对灌浆廊道补充帷幕灌浆,对排水廊道进行固结+帷幕+回填灌浆。通过灌浆处理后,效果良好,表明灌浆工程有效的将导致坝基渗漏的上下游的裂隙通道封闭,并顺利的经受了随后的汛期洪水考验,大坝安全得到保障。     

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.     

Calculation of the Inverse of the Covariance

In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix.     

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.