“三江”地区与青藏高原内部早第三纪高镁钾质岩地球化学对比:地幔源区的差异及其意义

"三江"地区和青藏高原内部广泛分布有新生代早第三纪高镁钾质岩(MgO6%,K2O/Na2O1),通常认为它们应起源于地幔源区,虽然它们均有着富钾、富集LILE和亏损HFSE的共同特征,并在形成时代上有着一致性,但青藏高原这些在不同区域的早第三纪火山岩在地球化学特征有显著的差异。"三江"地区同高原内部高镁钾质岩相比具有明显高的εNd(t)值,指示前者起源于一个相对亏损的富集地幔源区。青藏高原早第三纪高镁钾质岩可能源于与古俯冲环境相联系的富集地幔源区,但不同地区的富集物质和地幔源区矿物组成以及形成深度却是各不同。青藏高原内部高镁钾质岩的形成可能与高原腹部始新世下地壳的拆沉有关;而"三江"地区早第三纪高镁钾质岩可能与发生在50～40Ma北向俯冲的特提斯大洋板片断离有关。同时早第三纪特提斯大洋板片的北向俯冲和断离对"三江"地区在该时期的成矿物质的富集和成矿过程有着重要的贡献。     

青藏高原西部赛利普中新世火山岩源区:地球化学及Sr-Nd同位素制约

青藏高原拉萨地块西部赛利普地区新生代火山岩依据主量元素可划分为超钾质、钾质和钙碱性系列,主要的岩石类型为粗面安山岩、粗面岩,一个超钾质岩石的40Ar-39Ar年龄为17.58Ma,指示出火山活动为中新世.超钾质、钾质和钙碱性火山岩都显示出富集LREE及LILE(Th、U)、亏损HFSE(Nb、Ta、Ti)的特征.超钾质火山岩具有较高的K2O(6.31%～8.55%)、MgO(6.75%～8.96%)、Cr(270.7×10-6～460.4×10-6)、Ni(142.3×10-6～233.9×10-6)含量,较高的(87Sr/86Sr)i(0.71883～0.72732)和较低的εNd(-14.78～-15.37),指示可能起源于一个前期亏损并经后期俯冲作用改造的富钾的方辉橄榄岩富集地幔源区.钾质火山岩具有比超钾质火山岩低的K2O、MgO、Cr、Ni含量以及高的Ba、Sr含量,初始87Sr/86Sr为0.71553～0.71628,初始143Nd/144Nd为0.51197～0.51198,在空间上与超钾质火山岩共生,可能是前者母岩浆的演化产物.钙碱性火山岩具有较高的Sr(881.7×10-6～1309.2×10-6)、Sr/Y比值(50～108)和较低的Y(12.05×10-6～18.02×10-6),明显亏损重稀土Yb(0.93×10-6～1.30×10-6),类似于典型的埃达克质岩成分特征但相对高钾,并具有相对低的(87Sr/86Sr);(0.70928～0.71374)以及高的εNd(-7.90～-10.91),指示起源于富钾增厚下地壳物质的部分熔融.区域上拉萨地块超钾质岩、钾质岩与N-S向地堑系在空间上共存、时间上相吻合,由此本文认为拉萨地块中新世钾质.超钾质岩和南北向地堑系的形成可能与中新世早期北向俯冲的印度大陆岩石圈断离有关.     

藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩同位素地球化学研究

通过对藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩Sr,Nd,Pb同位素成分的系统测试分析表明,火山岩具有相对高的^87Sr／^86Sr和低的^143Nd／^144Nd值及高的Pb同位素组成特点,且Sr,Nd,Pb同位素比值变化范围很窄,反映了其具有同源岩浆的特点,并且经历了类似的地球化学动力学过程。Sr,Nd,Pb同位素组成及相关图解判别表明,藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩来源于被大洋沉积物和地壳物质所混合的不均一富集地幔源区,显示源区具有壳幔混源性质,与EMⅡ型富集地幔源特征一致。     

青藏高原拉萨地块新生代超钾质岩与南北向地堑成因关系

青藏高原拉萨地块广泛分布有新生代超钾质岩,岩石地球化学和Sr-Nd-Pb同位素特征表明这些超钾质岩来源于与古俯冲环境有着密切联系的含金云母的富集地幔源区,它们主要喷发于25~10 Ma。同时在拉萨地块分布有多条南北向地堑(裂谷),且它们的切割深度可能到达下地壳的深部甚至岩石圈地幔,它们主要形成于23~8 Ma。拉萨地块大多数超钾质岩沿着新生代的南北向地堑(裂谷)分布,并且它们在形成时代和空间分布上存在着明显的耦合性,结合沿着印度-雅鲁藏布江缝合带分布的中新世埃达克质岩,笔者认为这些超钾质岩很可能与中新世早期北向俯冲的印度岩石圈沿着印度-雅鲁藏布江缝合带附近发生断离,以及由此而引起拉萨地块东西向伸展构造活动产生的南北向地堑(裂谷)系统有关。     

中亚造山带中新生代壳幔相互作用特征与过程——新疆北部幔源岩浆岩系对比研究

新疆北部中新生代幔源岩浆岩多位于大型走滑断裂带或者裂谷带附近,岩石系列均具有高的TiO_2含量,富碱、高度富集不相容元素和轻稀土(LREE),ε_(Nd)(t)值低正值到负值,(~(87)Sr/~(86)Sr)_i值较高,不相容元素比值La/Nb和Nb/U显示中新生代玄武岩浆在形成过程中的壳幔作用明显不同于古生代造山过程,岩浆来源于类似OIB源的富集地幔。而新疆北部地区的二叠纪幔源镁铁-超镁铁岩来源于亏损地幔,陆壳物质参与了岩浆的形成,源区可能混入了早期的弧组分或俯冲的洋壳。由于古生代多个洋盆闭合和增生造山作用致使中亚造山带的岩石圈不断增厚,于古生代晚期发生拆沉去根作用,软流圈亏损地幔上涌形成二叠纪镁铁-超镁铁岩系,而拆沉的岩石圈以及俯冲下沉的洋壳及其沉积物,在地幔环境熔融交代改造原始地幔,使中亚地区的地幔自古生代晚期以后逐渐转换为整体富碱、富含轻稀土(LREE)和不相容元素的富集地幔。被改造了的富集地幔在中新生代沿裂谷带或大型走滑断裂薄弱带上涌,形成了中新生代幔源岩浆的喷发和侵位。     

青藏高原北部黑石北湖新生代钾质火山岩的成因

昆仑岩带新生代钾质火山活动是青藏高原北缘深部动力学过程的重要记录。有关岩浆源区的性质和岩浆产生的机制一直存在较大的认识分歧。阐述了昆仑岩带黑石北湖钾质火山岩的岩石学和地球化学特征,并与西昆仑康西瓦和泉水沟新生代火山岩进行了成因对比分析。研究表明,昆仑火山岩带玄武质岩石的K2O和Na2O含量变化较大,从钠质过渡到钾质,硅碱图显示玄武质初始岩浆向钾质安粗岩方向演化。黑石北湖火山岩的高场强元素和Sr、Nd同位素组成显示岩浆源区具有EMⅡ的性质。岩石LREE的强烈富集和HREE的强烈分馏指示岩浆来自富集型含石榴子石地幔源区。不相容元素K/Nb、Ba/La等比值具有岛弧火山岩与OIB型玄武岩的过渡特征,指示源区为曾遭受软流圈流（熔）体交代的古俯冲地幔楔。     

天山北部石炭纪埃达克岩-高镁安山岩-富Nb岛弧玄武质岩：对中亚造山带显生宙地壳增生与铜金成矿的意义

新疆天山北部地区存在有石炭纪的埃达克岩-高镁安山岩-富Nb玄武质岩组合，并且其中许多岩石与铜（金）矿床伴生（如达巴特、阿希、土屋-延东、赤湖，等等）。埃达克岩富钠、高Sr但亏损Y与Yb，无明显Eu-正Eu异常以及正Sr异常与Nb、Ti亏损。高镁安山（闪长）岩是本次研究首次报道的，这些岩石无明显Eu-正Eu异常以及Nb、Ti亏损，普遍具有高的MgO和Cr、Ni含量，其中阿希金矿区一些样品类似于日本西南新生代Setouchi弧火山岩带中的赞岐岩类。富Nb玄武质岩富钠贫钾，具有微弱负．正Ba、Nb和Ti异常以及高的Nb／La比值，不同于大多数正常岛弧玄武岩。天山北部地区石炭纪埃达克岩具有高的8Nd（t）（＋3．4-＋9．0）和低的（^87Sr／^86Sr）i（0．7032—0．7043）。富Nb玄武质岩具有变化的εNd（t）（＋3．6-＋11．6）和（^87Sr／^86Sr）；（0．7007—0．7067）。我们的研究表明，天山北部地区石炭纪埃达克岩-高镁安山岩-富Nb玄武质岩组合可能是“埃达克岩交代的岛弧岩浆岩系列”。埃达克岩最有可能由石炭纪北天山洋的年轻洋壳在俯冲过程中熔融形成。另外，俯冲板片产生的熔体以及所释放的少量流体在上升过程中可能交代地幔楔橄榄岩或与其发生反应：一方面，触发地幔楔橄榄岩发生熔融形成富Nb岛弧玄武质岩；另一方面，地幔组分迅速进入到板片熔体中，导致其地幔组分增加，乃至形成高镁安山岩。因此，天山北部地区石炭纪埃达克岩-高镁安山岩-富Nb玄武质岩组合表明：（1）天山北部地区石炭纪可能为岛弧环境而非裂谷环境；（2）天山地区石炭纪的地壳生长可能以侧向增生为主；（3）除了亏损地幔之外，俯冲洋壳的熔融可能也在地壳的生长中发挥了重要的作用；（4）俯冲板片产生的埃达克质岩浆具有高的氧逸度，而其与地幔楔橄榄岩的强烈相互作用将导致地幔中的金属硫化物分解，成矿金属元素进入到岩浆中。这可能是新疆北部铜金矿化与一些埃达克岩、高镁安山（闪长）岩或富Nb岛弧玄武质岩密切共生的基本原因。     

大别-苏鲁造山带南北两侧晚中生代富钾火山岩的成因：微量元素及Sr-Nd-Pb同位素制约

大别-苏鲁造山带南、北两侧广泛发育晚中生代富钾火山岩，主要岩石组合为粗面玄武岩-玄武粗安岩-粗安岩-安粗岩姐面岩，这套岩石总体具有富碱、富钾、富轻稀土和大离子亲石元素(如Rb、Th等)，贫高场强元素(如Nb、Ti等)，(^87Sr／^86Sr)，值偏高，εNd(t)值偏低等特点，但南、北两侧富钾火山岩的地球化学特征存在较显著的差异，主要表现在造山带北侧富钾火山岩稀土总量更高，轻、重稀土分异更明显，且(^87Sr／^86Sr)，值更高，eNd(t)值和^206Pb/^204Pb值显著偏低。元素-同位素综合示踪显示，区内富钾火山岩均起源于富集地幔的部分熔融，但南、北两侧源区地幔的富集机制存在差异，南侧富集地幔的形成主要与俯冲洋壳析出流体的交代作用有关，而北侧富集地幔的形成除受到俯冲洋壳析出流体的交代作用外，在更大程度上主要起因于俯冲的扬子陆壳析出流体的交代作用，即其源区遭受了多次富集事件的影响，后者是导致南、北两侧富钾火山岩地球化学特征差异的主要原因。     

青藏高原东部新生代钾质碱性系列岩石地球化学特征:岩石成因及其地质意义

青藏高原东部新生代钾质碱性系列的岩石,包括深成岩、火山岩和煌斑岩,在时空上具有一致性,岩石化学成分均富碱、高钾、K2O/Na2O比值远大于1,高度富集Sr、Ba等大离子亲石元素(LILE)和轻稀土元素(LREE),亏损Nb、Ta等高场强元素(HFSE),及物质来源于富集地幔源区的Sr、Nd、Pb同位素组成等,均显示钾质碱性系列的岩石特有的特征,其形成与印度和欧亚两大陆碰撞,导致青藏高原北、东部在40Ma左右出现的大型走滑拉分带,致使地壳变薄以及地幔上拱的构造背景有关。     

可可西里湖地区新生代火山岩同位素地球化学特征及火山成因、源区性质讨论

在青藏高原腹地可可西里地区发育一套新生代碱性、高钾钙碱性——钾玄岩火山岩类．由于该时期正是亚洲大陆内部岩石圈发生剧烈变形，青藏高原强烈隆升的重大变革时期，火山岩的形成在这些重大事件中扮演什么角色?很值得探讨。通过对区内火山岩Rb、Sr、Sm、Nd、Pb同位素的研究，在火山岩的岩浆来源、成因等方面获得了大量信息。研究表明；新生代火山岩主要来源于富集Ⅱ型地幔区，部分为具极高εSr和极低εNd的酸性火山岩，它是与区内钾质熔岩同源的晚期分异产物；碱性火山岩在成因上与板内初始裂谷有关。研究成果为青藏高原特有的“壳-幔混合层”的形成提供了证据。     

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。     

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。     

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.     

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.     

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。      

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″.     

Artemia in the Salt Lakes of Russia:the Productivity of Populations,the Reserves of the Cysts and the Fisheries

正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the