Eclogite facies metarodingites – phase relations in the system SiO2-Al2O3-Fe2O3-FeO-MgO-CaO-CO2-H2O: an example from the Zermatt-Saas ophiolite

Eclogite facies metarodingites occur as deformed dykes in serpentinites of the Zermatt‐Saas ophiolite (Western Alps). They formed during the subduction of the Tethys oceanic lithosphere in the Early Tertiary. The metarodingites developed as a consequence of serpentinization of the oceanic mantle. Three major types of metarodingites (R1, R2 & R3) can be distinguished on the basis of their mineralogical composition. All metarodingites contain vesuvianite, chlorite and hydrogrossular in high modal amounts. In addition they contain: R1 – diopside, tremolite, clinozoisite, calcite; R2 – hydroandradite, diopside, epidote, calcite; and R3 – hydroandradite. Both garnets contain a small but persistent amount of hydrogarnet component. The different metarodingites reflect different original dyke rocks in the mantle. In each group of metarodingite, textural relations suggest that reactions adjusted the assemblages along the P–T path travelled by the ophiolite during subduction and exhumation. Reactions and phase relations derived from local textures in metarodingite can be modelled in the eight‐component system: SiO₂‐Al₂O₃‐Fe₂O₃‐FeO‐MgO‐CaO‐CO₂‐H₂O. This permits the analysis of redox reactions in the presence of andradite garnet and epidote in many of the rocks. Within this system, the phase relations in eclogite facies metarodingites have been explored in terms of T–X_CO2, T–μ(SiO₂), μ(Cal)–μ(SiO₂) and P–T sections. It was found that rodingite assemblages are characterized by low μ(SiO₂) and low X_CO2 conditions. The low SiO₂ potential is externally imposed onto the rodingites by the large volume of antigorite‐forsterite serpentinites enclosing them. Moreover, μ(SiO₂) decreases consistently from metarodingite R1 to R3. The low μ(SiO₂) enforced by the serpentinites favours the formation of hydrogarnet and vesuvianite. Rodingite formation is commonly associated with hydrothermal alteration of oceanic lithosphere at the ocean floor, in particular to ocean floor serpentinization. Our analysis, however, suggests that the metarodingite assemblages may have formed at high‐pressure conditions in the subduction zone as a result of serpentinization of oceanic mantle by subduction zone fluids.     

A new computational strategy for solving two‐phase flow in strongly heterogeneous poroelastic media of evolving scales

We develop a new computational methodology for solving two‐phase flow in highly heterogeneous porous media incorporating geomechanical coupling subject to uncertainty in the poromechanical parameters. Within the framework of a staggered‐in‐time coupling algorithm, the numerical method proposed herein relies on a Petrov–Galerkin postprocessing approach projected on the Raviart–Thomas space to compute the Darcy velocity of the mixture in conjunction with a locally conservative higher order finite volume discretization of the nonlinear transport equation for the saturation and an operator splitting procedure based on the difference in the time‐scales of transport and geomechanics to compute the effects of transient porosity upon saturation. Notable features of the numerical modeling proposed herein are the local conservation properties inherited by the discrete fluxes that are crucial to correctly capture the fingering patterns arising from the interaction between heterogeneity and nonlinear viscous coupling. Water flooding in a poroelastic formation subject to an overburden is simulated with the geology characterized by multiscale self‐similar permeability and Young modulus random fields with power‐law covariance structure. Statistical moments of the poromechanical unknowns are computed within the framework of a high‐resolution Monte Carlo method. Numerical results illustrate the necessity of adopting locally conservative schemes to obtain reliable predictions of secondary recovery and finger growth in strongly heterogeneous deformable reservoirs. Copyright © 2011 John Wiley & Sons, Ltd.     

基坑降水总应力变化时有效应力增量和沉降量计算

针对基坑降水引起地面沉降计算值比实际值偏大的情况，本文系统分析了潜水和承压含水层在降水后，不同条件下土中总应力及有效应力的计算。基坑降水后土体中的总应力不是通常认为的一成不变。特别是基坑降水中常遇到的降低潜水含水层水头的情况，总应力是减小的，有效应力增量值也小于孔隙水压力下降值。对比分析了通常采用的不变原理和本文提出的可变原理两种情况，降水后土体总应力和有效应力增量计算值有差异，采用分层总和法计算了基于两种原理的沉降量。潜水含水土层沉降量计算偏差最大，基于总应力不变的沉降量比总应力可变的计算沉降量约大20%。本文计算原理对于抽取深层承压地下水导致地面沉降同样适用。     

新技术在城市地面沉降研究中的应用：遥感卫星雷达干涉测量（InSAR）

本文综述了遥感卫星合成孔径雷达（SAR）干涉测量及差分干涉测量的基本原理，针对近年来国外InSAR在地面沉降方面的研究成果，重点讨论了D－InSAR在国内大中城市进行地面沉降监测应用的可能性，对SAR数据的获取方法进行了阐述，并对这种方法目前的进展及未来应用前景进行了探讨。     

X射线衍射定量分相分析的策略架构

引入分析策略的概念，揭示了当代研究X射线衍射定量相分析方法的正确途径。通过策略的系统演绎，对现今X射线定量相分析的基本方法进行了全面的构筑和科学分类，总共有7类分析方法，分别称之为内标消约法、外标消约法、样内异相消约法、样间异相消约法、样间同相消约法、归并C值法和理论计算法，并对各类方法的固有特点作了全面的概括。阐述了如何用现代谱图拟合技术进行常规定量方法的扩展以实现择优取向的强度修正。     

乌鲁木齐附近地区小爆破识别判据的研究

采用新疆乌鲁木齐地区多个地震台的位移仪及速度仪记录，探讨了人工小爆破记录与天然地震记录的差异及其识别判据。结果发现，爆破记录与地震记录在震相、P波垂直向初动符号分布、振幅衰减、振幅比As^-/Ap^-等方面具有不同的特征，据此我们制定出了识别爆破的单项判据和综合判据。     

400℃Cu—Bi—Te三元系及相平衡关系

利用干法真空石英玻璃管合成实验方法成功地构筑了Cu-Bi-Te三元系400℃时的相平衡图。在此实验温度条件下，该相图中除了存在着8个已知的矿物相、1个合成的Bi-Te二元相和2个液相共熔区外，同时还存在着一个新的Cu-Te二元相Cu9Te5以及两个Cu-Bi-Te三元相CuBiTe和Cu3BiTe3。     

分布式被动源电磁法系统及其应用

分布式被动源电磁法系统 ,简称DPEM。DPEM利用天然电磁场或人文电磁场作为源场 ,研究大地的电磁响应 ,探测地下电性分布及地质结构 ,可适应各种复杂的地理地质环境。主要特点有 :同步阵列遥测不同地理坐标点的电磁场 ,具有高信噪比、高分辨率和高效率 ;主机 -子机系统 ,为非封闭挂接式 ,可按使用要求配置子机数量 (坐标点数 ) ,一次实现面积性同步覆盖测量 ;频率范围 16kHz～ 0Hz ,实现浅自近地表、深至 1km、直至上地幔的不同地质目标的探测 ;可提供视电阻率、阻抗相位、异常相位等地电学参数。文中介绍了 3个工作实例     

李雅普诺夫不稳定性与暴雨发生的关系

用李雅普诺夫稳定性理论第二方法的概念，找出一个与大气扰动微分方程组有关的李雅普诺夫函数δ￣２Ｓ，用δ￣２Ｓ与其导数乘积的符号确定系统的稳定性，诊断暴雨落区和强度。在１９９３年６～８月暴雨预报试验中，三峡地区发生８次暴雨过程，报出５次。     

目标规划方法在地下水资源管理中的应用

以满意决策理论为基础，针对地下水分布多数系统资源管理中关于建模和决策方面的某些突出问题，分析了用目标规划方法解决这些问题的基本思路，并结合某市水资源管理实例，讨论了目标规划方法的建模过程、求解方法、决策过程及其意义。