华北克拉通基性火山岩高场强元素对Ar-Pt界限及新生代地幔源区特征的示踪

华北克拉通不同时代基性火山岩存在向富集方向演化的趋势,并出现明显的Ａｒ－Ｐｔ界限和新生代异常．元古宙基性火山岩比太古宙富集大部分高场强元素（ＨＦＳＥ）和轻稀土元素（ＬＲＥＥ）,ＲＥＥ分异程度显著增加,而且相容性接近的不相容元素（如Ｎｂ,Ｔａ）的相对不相容性发生了改变．新生代玄武岩ＨＦＳＥ及Ｎｉ高度富集,ＲＥＥ强烈分异,δ（Ｅｕ）值最高．Ａｒ－Ｐｔ界限可能与地幔熔融时物理条件（如氧逸度）的改变和地幔富集作用有关．新生代玄武岩独特的地球化学特征可能主要反映了地幔源区的特殊性———“似ＯＩＢ型”富集地幔,其形成既可能有携带远洋沉积物的俯冲古老玄武岩洋壳部分熔融残余的贡献,也可能有直接循环（如通过拆沉作用）的陆壳物质的贡献,同时还可能涉及了地幔柱活动的影响．     

Differences in trace metal concentrations among fluvial morphologic units and implications for sampling

 This study examines the segregation of trace metals within and between fluvial morphologic units in sand-sized and finer bed sediments in a cobble bed stream. The types of fluvial morphologic units sampled are low gradient riffles, high gradient riffles, glides, eddy drop zones, lateral scour pools, attached bars, and detached bars. Three to nine samples were collected from ten of each type of morphologic unit. All 12 metals show significantly different concentrations between some morphologic units in sediments smaller than 2 mm. Eddy drop zones and attached bars consistently have the highest metal concentrations, while low gradient riffles, high gradient riffles, and glides typically have the lowest concentrations. Metals showing the greatest between-unit variability are Al, Cr, Fe, Cu, and Ti, followed by Co, Mn, and Pb, while Mg, Mn, V, and Zn display relatively few differences between units. Lateral and longitudinal variations of metals within units are not significant, and there was no consistent, predictable variation in metal concentrations with distance downstream. Results indicate that metal studies in other gravel- and cobble-bed streams should include a reconnaissance survey to determine variations between morphologic units, stratify sampling by morphologic unit, and analyze spatial autocorrelation to determine sample spacing. Received: October 1997 · Accepted: 23 March 1998     

某古岩溶铀矿床中铀,钼,铼的赋存状态

本文采用电子探针、透射电镜和化学物相法,查明某古岩溶铀矿床中铀主要呈显微和超显微状沥青铀矿、铀石,其次呈分散吸附状和铀酰（次生）矿物形态存在;钼主要呈蓝钼矿、钼钙矿、钼华、钼铅矿等氧化物,其次呈胶硫钼矿等形态存在;铼主要呈吸附状,其次可能在黄铁矿中呈二硫化物包裹体形态产出。最后讨论了该三个元素赋存状态与该铀矿床形成地球化学环境之间的关系。     

三维结线动力无穷元及其特性研究

研究了文献[2]提出的结线动力无穷元的特性及其参数确定。由于这种单元将衰减函数定义在无穷向结线上,从而不仅可同时考虑多种波动形式,而且对于不同介质,不必通过改变节点坐标分布的形式实现介质间的过渡,而直接以结线上参数的改变来实现,因而可以更好地模拟无穷波动场,使用起来更方便．更容易推广。     

三维复杂域非结构化六面体网格全自动生成方法

使用自适应有限单元法在三维复杂域内求解水工及岩土工程问题,讨论了应用行波法在多介质三维复杂块体内六面体单元网格的自动生成过程。其特点是对不规则区域具有较强的适应性,并考虑了节理单元的自动生成。     

地质流体热动力学研究现状与发展趋势

流体热动力学性质对理解各种作用过程中的地球化学行为是重要的。有关这方面的知识,通常是从实验资料获得。但实验工作毕竟是有限的,只能反映自然条件中很有限的范围。半经验的模式（如状态方程）或计算机模拟（如分子动力学和ＭｏｎｔｅＣａｒｌｏ模拟）提供了地质流体系统定量研究的主要方法。一个好的状态方程,可以根据实验数据内插或外延,能获得很多物理—化学信息。计算机模拟甚至可以在实验室不能达到的条件下产生“实验数据”,为未来地球化学研究提供了很大的潜在发展可能性。未来研究工作的重点应是：①为Ｈ２Ｏ－ＣａＣｌ２－ＮａＣｌ－ＣＯ２－ＣＨ４－Ｈ２Ｓ－Ｎ２体系提供预测容积、相平衡和焓的状态方程;②有效的计算机程序能够模拟自然界中含水溶液流体混合物的各种特性（包括热动力、结构、迁移性质）;③将这些模式和计算机模拟应用于各种地质系统的研究（如热水溶液矿床和流体—岩石交换反应等）中。     

岩土工程数值模拟新方法

论述了岩土工程数值模拟的新进展和近年来新出现的数值模拟方法,重点介绍了无网络伽辽金法（ＥＦＧＭ）和数值流形法（ＭＭ）的原理及其在岩土工程中的应用,指出了今后研究的重点方向。     

Remarkable response amplification of building frames due to resonance with the surface ground

Seismic response of a building structure is influenced greatly by soil-structure interaction. This fact has been demonstrated in the past earthquakes. It is shown that tuning of the natural period of a building structure with that of a surface ground causes remarkable response amplification of the building structure. Introduction of an overall system as a building-pile-soil system is inevitable to investigate such a tuning effect. It is demonstrated to be essential to define a design earthquake at a bedrock level in order to guarantee the structural safety of building structures under seismic disturbances. Comparison of the response due to input of double the upward-propagating wave (an outcropping motion) into the bedrock without any viscous boundary with that due to input of an within motion into the bedrock without any viscous boundary is also shown in order to investigate the effect of input motions on the response of the superstructure.     

Recent tectonic stress field research in Shanxi graben system

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长江中下游及邻区基底和花岗岩成矿元素丰度背景的研究

本文系统地研究了长江中下游及邻区的结晶基底,褶皱基底及花岗岩岩基成矿元素丰度背景,从而为区域Ｃｕ、Ａｕ,Ｗ、Ｓｎ等成矿作用提供了一套完整的基础地球化学数据,用此来作为窥视地壳组成及成矿作用时空演变的窗口。