A multi‐level parallelized substructuring‐frontal solution for coupled thermo/hydro/mechanical problems in unsaturated soil

This paper proposes a multi‐level parallelized substructuring–frontal combined algorithm for the analysis of the problem of thermo/hydraulic/mechanical behaviour of unsaturated soil. Temperature, displacement, pore water pressure and pore air pressure are treated as the primary variables in a non‐linear analysis. Details are given firstly of the substructuring–frontal combined approach. The incorporation of the algorithm in a multi‐level parallel strategy is then discussed. The parallel processing can thus be carried out at different substructural levels. The method thus developed impacts, in a positive way, on both computer storage requirement and execution time. Copyright © 2003 John Wiley & Sons, Ltd.     

Himalayan magmatism and porphyry copper–molybdenum mineralization in the Yulong ore belt, East Tibet

Summary ?The NW–SE-trending Yulong porphyry Cu–Mo ore belt, situated in the Sanjiang0 area of eastern Tibet, is approximately 400 km long and 35 to 70 km wide. Complex tectonic and magmatic processes during the Himalayan epoch have given rise to favorable conditions for porphyry-type Cu–Mo mineralization. Porphyry masses of the Himalayan epoch in the Yulong ore belt are distributed in groups along regional NW–SE striking tectonic lineaments. They were emplaced mainly into Triassic and Lower Permian sedimentary-volcanic rocks. K–Ar und U–Pb isotopic datings give an intrusion age range of 57–26 Ma. The porphyries are mainly of biotite monzogranitic and biotite syenogranitic compositions. Geological and geochemical data indicate that the various porphyritic intrusions in the belt had a common or similar magma source, are metaluminous to peraluminous, Nb–Y–Ba-depleted, I-type granitoids, and belong to the high-K calc-alkaline series. Within the Yulong subvolcanic belt a number of porphyry stocks bear typical porphyry type Cu–Mo alteration and mineralization. The most prominent porphyry Co–Mo deposits include Yulong, Malasongduo, Duoxiasongduo, Mangzong and Zhanaga, of which Yulong is one of the largest porphyry Cu (Mo) deposits in China with approximately 8 × 10⁶ tons of contained Cu metal. Hydrothermal alteration at Yulong developed around a biotite–monzogranitic porphyry stock that was emplaced within Upper Triassic limestone, siltstone and mudstone. The earliest alteration was due to the effects of contact metamorphism of the country rocks and alkali metasomatism (potassic alteration) within and around the porphyry body. The alteration of this stage was accompanied by a small amount of disseminated and veinlet Cu–Mo sulfide mineralization. Later alteration–mineralization zones form more or less concentric shells around the potassic zone, around which are distributed a phyllic or quartz–sericite–pyrite zone, a silicification and argillic zone, and a propylitic zone. Fluid inclusion data indicate that three types of fluids were involved in the alteration–mineralization processes: (1) early high temperature (660–420 °C) and high salinity (30–51 wt% NaCl equiv) fluids responsible for the potassic alteration and the earliest disseminated and/or veinlet Cu–Mo sulfide mineralization; (2) intermediate unmixed fluids corresponding to phyllic alteration and most Cu–Mo sulfide mineralization, with salinities of 30–50 wt% NaCl equiv and homogenization temperatures of 460–280 °C; and (3) late low to moderate temperature (300–160 °C) and low salinity (6–13 wt% NaCl equiv) fluids responsible for argillic and propylitic alteration. Hydrogen and oxygen isotopic studies show that the early hydrothermal fluids are of magmatic origin and were succeeded by increasing amounts of meteoric-derived convective waters. Sulfur isotopes also indicate a magmatic source for the sulfur in the early sulfide mineralization, with the increasing addition of sedimentary sulfur outward from the porphyry stock. Received August 29, 2001; revised version accepted May 1, 2002 Published online: November 29, 2002     

南海沉积岩芯的地球化学研究

本文对南海中部陆坡区和海盆区的5个岩芯中的 Si,Al,Fe,Mn,Ca,Mg 和 CaCO_3成分做了分析,并对其分布特征与有关影响因素进行了讨论。受沉积区环境差异的影响,元素的分布具有区域性特征;受海区特定地理位置的影响,元素的分布呈现出过渡性特征(浅海到大洋的过渡);受沉积过程中环境变化的影响,元素的分布展示了周期性变化或旋回性。根据岩芯中元素的分布特征,并参考有关古地磁,氧碳同位素和钙质超微化石的测试分析结果,将本区岩芯划分为14层地球化学层,并将本区划分为两个沉积地球化学区,揭示了早更新世以来本区沉积环境的变化和存在的两种沉积模式。     

闽南：台湾浅滩渔场变性水团的初步分析

根据聚类方法，对闽南－台湾浅滩渔场变性水团进行划分，本海区共有６个变性水团。讨论各个变性水团在不同季节消长变化规律。     

厦门筼筜港的形成与演变

本文根据实际调查的资料,概述了筼筜港区的地质地貌特征,重点论述了第四纪沉积物的成因和时代,阐述了该区的形成与演变过程,把它划分为5个发育阶段。     

热带地区流场异常与江淮特大暴雨成因的研究

本文通过计算和对比分析，得到１９９１年春、夏江淮地区特大暴雨形成的五个基本特征：西北太平洋上副高显著偏西、偏北；较弱的西南季风与东南气流汇合成强西南气流伸向江淮地区；偏东风与强西南风形成的辐合带在江淮地区维持；江淮地区对流层中下部为强上升运动、上部为辐散；１３０°Ｅ附近南半球向北半球的较强越赤道气流持续。     

中国海岸风成沙ESR测年的研究

介绍ＥＳＲ测年的基本原理，并讨论风成沙Ｇｅ心测年的可行性、风成沙Ｅ＇心的特征、测年误差及可靠性等问题。１９９２－１９９３年在渤、黄、东、南海沿岸采集的１００余个风成沙样品ＥＳＲ测年实验表明，绝大部分海岸风成沙的年龄为１－７万年。     

不同树龄桐花树茎上白条地藤壶分布特征的研究

研究了广西英罗港红树林区向海林带不同树龄的桐花树茎上白条地藤壶的分布特征。结果表明，白条地藤壶在茎上的附着高度（h)随树龄和树高增大而增大。在最大树龄17龄植株上平均达到182cm，此高度为潮高约512cm海水才能浸及，在一年中约有将近90％的时间暴露在空气中。附着高度（h)与树高（H）比值h/H以5龄树最大，达91．9％。树层最大密度达46600Ind/m^2，最小为172Ind/m^2。在同一树龄的不同树层，密度表现为先随树高增大逐渐增大，达到最大密度后又下降。在不同树龄的同一树层，密度高低变化，分布一般出现多个峰。白条地藤壶最适宜附着和生长在桐花树茎上100－120cm树层（浸及此树层的海水潮高约为430－450cm)。树层最大生物量为1719．05g/m^2，最小为5．39g/m^2。生物量分布与密度的相似。     

Objective prism survey of qsos in the field centered at 10h40m + 00°00′

QSO objective prism survey was done for the field centered at 10^h40^m + 00°00. For the 348 objects selected, we present in this paper their positions,B _J magnitudes, spectra, and finding charts. Based on the sample containing 163 QSO candidates with higher reliabilities (F 3), the surface density of QSO candidates withB _J 20 is estimated to be about 4.5 per square degree.Work based on UKST plates.     

Slip-weakening constitutive relation and the structure in the vicinity of a shear crack tip

Shear-crack model with a cohesive zone (or breakdown zone) is appropriate for the analysis of a fault surface in which slip distribution is strongly nonuniform. As the slipped portion advances, slip-weakening occurs over the so-called cohesive zone, a distance behind the fault tip. For a prescribed strength vs. displacement constitutive relation, however, the zone structure is difficult to determine by an analytical method except for some simple cases, thus it often requires a certain numerical procedure. This work proposes a numerical procedure to obtain approximated solutions of the problem by combining a series of elastic solutions derived bySmith (1974). The series is linearly combined and the unknown coefficients are determined by a nonlinear least square method. This method can fit a wide range of prescribed strength vs. displacement relations which may be simple algebraic relations or curves obtained by laboratory tests. By examining the residual errors and in comparison with a derived result in which linear stress is assumed within the zone, it could be concluded that the results provide good accuracy. Moreover, because the results are written in formulae, they can be easily referred to or used. By fitting constitutive curves in many different shapes, it is found that the stress distribution within the zone is more sensitive to the constitutive curve shape than the displacement. The most interesting fact is that the zone size is not sensitive to the curve shape, i.e., the zone size can be estimated by $$R = 3\mu \zeta \upsilon _c /\{ 2(1 - \upsilon )(\tau _c - \tau _f )\}$$ with ζ=1±0.11 for most cases.