鲜水河断裂带现今断层运动短周期事件的发现与初步研究

根据鲜水河断裂带上连续动态地壳形变台阵数据，首次揭示了中国大陆板内断层现今运动的短周期现象，包括蠕变阶、蠕变坡和脉动等，其持续时间为数分钟至数十小时。发现其空间分布与断层分段（闭锁或活动段）有关；其时间分布与强地震孕育过程有关。蠕变过程符合Ｌｏｍｎｉｚ提出的对数蠕变函数，可能是断层面不均匀结构中的局部流变行为。断层短周期事件对揭示断层不均匀结构和微破裂过程动力学有重要意义，并可能发展为一种新的地震前兆     

Chronology and Geochemistry of Volcanic Rocks in the Cretaceous Suifenhe Formation in Eastern Heilongjiang, China

Zircon U-Pb ages and geochemical data of volcanic rocks in the Suifenhe Formation in eastern Heilongjiang Province are reported, and their petrogenesis is discussed in this paper. The Suifenhe Formation mainly consists of basalt, andesite, and dacite. Zircon from andesite and dacite are euhedral in shape and show typical oscillatory zoning with high Th/U ratios (0.18-0.57), implying its magmatic origin. Zircon U-Pb dating results by laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) indicate that the 206Pb/238U ages of zircons from andesite range within 105-106 Ma, yielding a weighted mean age of 105.5±0.8 Ma (n=14), and that 206Pb/238U ages of zircons from dacite are between 90-96 Ma, yielding a weighted mean age of 93.2±1.3 Ma (n =13). The volcanic rocks from the Suifenhe Formation are subalkaline series and show a calc-alkaline evolutionary trend with SiO2 content of 47.69%-65.47%, MgO contents of 1.42%-6.80% (Mg#= 45-53), and Na2O/K2O ratios of 1.83-3.63. They are characterized by enrichment in large ion lithophile elements (LILE) and light-rare-earth elements (LREE), depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE) (e.g., Nb, Ta, Ti), and low initial 87Sr/86Sr ratios (0.7041-0.7057) and positiveεNd(t) values (039-4.08), implying that they could be derived from a depleted magma source. Taken together, these results suggest that the primary magma of the volcanic rocks might originate from partial melting of the mantle wedge metasomatized by fluids derived from subducted slab under a tectonic setting of active continental margin.     

乐平统底界定义和点位的争论

有关乐平统底界定义和点位的争论涉及到有关建立界线层型的一些基本原则。本文作者确信,乐平统的底界不可能建立在小间断上或层序界面上;不能被证实的点断成种事件也不能用来建立界线层型;定义种在连续演化谱系中首现的点位是确定的不是任意的;必须考虑定义种的首现时期的居群特征,不能用定义种晚期的居群特征来确定GSSP的点位;定义种的定义不能任意改动,要保持分类的稳定。不能过高估计或只认为齿脊特征是区别晚二叠世舟刺分子的唯一标准。梅仕龙有关C. postbitteri和C. dukouensis两个种区别特征的争辩是无用的,因为本文作者所使用的区别这两个种的标准正是梅仕龙等(Mei et al, 1994)所提出的。现在没有必要为维护自己的界线定义或点位而修改有关种的定义。原来有关这两个种的定义和区别特征是科学的。本文作者鉴定的C. dukouensis (Wang, 2000a, p1. 2, figs. 1～8)是正确的,符合原来的定义。乐平统底界定义应当是严格的科学的。金玉玕等(Jin et al, 1994, 1998)从来没有提到更谈不上“反复讨论”了C. doukouensis的“首现”(梅仕龙,本期)。虽然提到(C. postbitteri的首现,但由于C. postbitteri的先驱种不清,这个定义是不科学的。乐平统底界的科学而严格的定义应是:在Clarkikina postbitteri—C. duk     

钇易解石族的端员—钛钇易解石的发现

本矿物为新发现的钇易解石族的端员矿物－钛钇易解石，产于江西省龙南县足洞燕山期中粒白云母花岗岩及其风化壳中。矿物属斜方晶系，常呈板状或短柱状，为天然晶质体，浅黄色，粒度为０．０７５ｍｍ，硬度４．７，比重４．７３，二轴正晶，Ｎｇ＝２．２４８，Ｎｍ＝２．２１２，Ｎｐ＝２．１９４，Ｎｇ－Ｎｐ＝０．０５４，２Ｖ＝７０°。空间群为Ｄ＾１６２ｈ－Ｐｍｎｂ，ａ０＝０．７５０ｎｍ，ｂ０＝１．０９２ｎｍ，Ｃ０＝０．５     

Analysis of Offshore Oil Pipeline Floating Laying

-Based on the calculation model for the floating laying of the offshore oil pipeline, this paper analyses in detail the internal force, and deformation of the pipeline under a definite structural form (pipeline and buoy) and the way of pulling. The obtained results can be used for the buoy deployment, structure design, and the determination of pulling parameters (the pulling force of the cable and its length, etc.), providing an effective analysis method for floating pipeline-laying. A calculation example is given to show the related calculation process and the main results are analyzed and discussed.     

松潘-甘孜地体内花岗岩锆石SHRIMP U-Pb定年及其构造意义

松潘-甘孜地体总体上是一个三角状褶皱带,其北侧、东南侧及东侧分别与东昆仑-西秦岭构造带、金沙江构造带及龙门山构造带相邻。地体内几乎全部被三叠系浊积岩所覆盖,其中侵位了很多花岗岩体。显然,这些花岗岩的岩浆特征、来源与侵位时代,对研究松潘-甘孜地体基底性质、构造演化等问题具有重要意义。本文报道利用SHRIMP定年技术对一些花岗岩岩体锆石所进行的精确测年数据。测试结果表明:(1)松潘-甘孜地体内的花岗岩体主要形成于晚三叠世,但岩浆活动可延续到早侏罗世晚期;(2)早期花岗岩浆活动与三叠纪系褶皱变形大致同期,指示这一时期的花岗岩浆的形成可能与三叠系下部大型拆离滑脱构造相关;(3)花岗岩结晶锆石普遍具有浑圆状或不规则状较老的继承锆石核,这些核部继承锆石可能代表花岗岩浆在上升过程中从不同地层内捕获的碎屑锆石,或者是下地壳岩石深熔残留锆石。根据SHRING U-Pb定年,这些继承锆石的年龄分别为二叠纪、加里东期、晚元古代和早元古代。元古代碎屑锆石的存在也可能指示松潘-甘孜地体具前寒武系基底。     

Elasto-Plastic Analysis of Tubular Joints of Offshore Platforms by Finite Element Method

The plastic node method is reformulated by the variational principle and is applied to elasto-plastic finite element analysis of tubular joints, eventually including the effect of internal and external gussets, stiffener rings, etc., if necessary. Four different joints are studied here in detail for the elasto-plastic behavior, the strain at the hot spot, the strain concentration factor around the intersection line, and the propagation of the plastic region with loading up to collapse in order to determine the ultimate strength, safety factor, and development of the plastic field. The present results are in good agreement with the experimental results.     

MULTIVARIATE RESPONSE SURFACE MODELLING BY PRINCIPAL COMPONENTS ANALYSIS

Analysis of multivariate response data by modelling the principal components of the response has beenapplied to two sets of data. In both cases principal components analysis revealed the relationships amongthe response variables and exploited them to simplify the problem of modelling and optimizing themultivariate response. The models and optima obtained from the principal components comparedfavourably with the individual models and simultaneous optima.     

大同—阳高Ms6.1地震前兆综合加权信息熵的变化

利用“地震预报计算机专家系统”的思想对大同 -阳高 Ms6 .1地震前每一前兆异常事件进行综合评估 ,以每一异常的最可能发震时间来计算发震概率 ,利用地震前兆综合加权信息熵研究了系统熵值与地震的关系。对华北地区的地震前兆综合加权信息熵研究表明 ,在大同 -阳高 Ms6 .1地震前 ,信息熵出现了明显的减熵有序变化     

Ordovician Intrusive-related Gold-Copper Mineralization in West-Central New South Wales, Australia

Three major types of Ordovician intrusive-related gold-copper deposits are recognized in central-west New South Wales, Australia: porphyry, skarn and high sulphidation epithermal deposits. These deposits are mainly distributed within two Ordovician volcano-intrusive belts of the Lachlan Fold Belt: the Orange-Wellington Belt and the Parkes-Narromine Belt. Available isotopic age data suggest that mineralization of the three types of deposits is essentially coeval with the Ordovician intrusive rocks (480-430 Ma).Porphyry gold-copper deposits can be further divided into two groups. The first group is associated with monzonite showing shoshonitic features, represented by Cadia and Goonumbla. The second group is associated with diorite and dacite, including the Copper Hill and Cargo gold-copper deposits. Gold skarn is associated with Late Ordovician (430-439 Ma) monzonitic intrusive complexes in the Junction Reefs area (Sheahan-Grants, Frenchmans, and Cor-nishmens), Endeavour 6, 7 and 44, Big and Little Cadia