Chemical equilibria of thermal waters for the application of geothermometers from the Guanzhong basin, China

In this study, representative samples from thermal wells and springs were chemically analyzed and geothermometers were used to calculate the deep temperatures of geothermal reservoirs on the basis of water–mineral equilibrium. In some cases, however, the chemical components are not in equilibrium with the minerals in the reservoir. Therefore, log(Q/K) diagrams are used to study the chemical equilibrium for the minerals that are likely to participate. The Na–K–Mg triangular diagram is also applied to evaluate the equilibrium of water with reservoir rocks. Standard curves at the reference temperatures are prepared to reveal which type of silica geothermometer is appropriate for the specified condition. This study shows that water samples from geothermal wells W9 and W12 are in equilibrium with the selective minerals, and chalcedony may control the fluid–silica equilibrium. It is estimated that there is an exploitable low-temperature reservoir with possible temperatures of 80–90°C in the Guanzhong basin.     

姑山铁矿东帮河堤的稳定性分析

基于极限平衡理论，采用以简化毕肖普法为主，费伦纽斯法作为参照的分析方法，对姑山铁矿采矿场东帮及青山河河堤防渗加固后的稳定性进行了分析评价，根据不同的爆破震动大小，得出背水面和迎水面多个安全系数值，取得了较为可靠的分析结果。     

含矿流体混合反应与成矿作用的动力平衡模拟研究

本文在约定热液体系中成矿元素成矿速率(成矿过程中单位时间内单位体积所合成矿元素重量的变化)的基础上。借助于物质-热-化学-成矿四重全耦合的研究思路，构建了均匀热液体系、层状热液体系、岩浆侵入热液体系下成矿元素的迁移、富集、溶解与沉淀作用数值模型。模拟结果表明；(1)硫化物(H2S)和硫酸盐(SO42-)流体的混合反应是成矿热液体系中铅、锌、铁成矿元素成矿的重要控制因素；(2)均匀介质、岩浆侵入或地质构造的存在，对成矿元素在成矿流体运移的速度、流线、温度分布和成矿元素的溶解与沉淀分布都有着各自的特征．不同的成矿环境或成矿背景制约了成矿元素的迁移与富集以及矿体的产出定位。暗示成矿环境及成矿速率对热液体系中成矿元素的沉淀与溶解具重要作用；成矿流体的混合反应是成矿作用发生的重要机制之一。在成矿理论研究中必须充分考虑不同地质构造因素的约束。     

高斯平面坐标换算到测区平均高程面上的方法

依据高斯投影原理，提出了一种在高斯平面与任决高程平面间进行坐标转换的方法，并设计了相应的计算软件。     

正常椭球内部场的内蕴几何与密度分布

将重力场内蕴几何结构的研究引入到正常椭球内部场的研究中，深入探讨了内蕴几何量及其与内部物理量之间的关系，并据此建立了弱平衡条件下的基本微分方程，进而给出确定椭球内部内蕴几何量与场源密度分布的方法。研究表明，平衡形状理论中的Ｗａｖｒｅ公式和Ｃｌａｉｒａｕｔ方程可由内蕴几何与内部物理量之间的关系导出，它们是在平衡假设下取椭球近似的结果。     

橄榄岩中尖晶石的O同位素继承性与晶体结构转换

应用增量法计算的矿物对O同位素分馏曲线，得到正尖晶石-矿物对O同位素温度高于尖晶石在地幔中的熔点，而用反尖晶石-矿物对计算的O同位素温度低于尖晶石的熔点，较为合理。因此，地幔橄榄岩中镁铝尖晶石的O同位素组成可能继承了其母体反尖晶石特征，即使反结构尖晶石在发生相变作用变成正结构尖晶石时未发生O同位素再平衡。     

Disequilibrium for Ca during growth of pelitic garnet

Compositional zoning in hundreds of almandine-rich garnets in amphibolite by facies micaceous quartzites from the Picuris Range, north-central New Mexico USA, indicates that although Mn, Mg and Fe achieve chemical equilibrium at hand-sample scale during garnet growth, Ca does not. Instead, Ca concentrations at the surface of growing garnets appear to depend strongly on kinetic factors that govern the local chemical environment, yielding disequilibrium for Ca at scales larger than the region immediately surrounding an individual porphyroblast. Detailed zoning profiles were obtained for 371 garnet crystals in a small volume of a single sample of garnetiferous quartzite, and core analyses were made of 97 additional crystals. Each analysis was made on a section that passed precisely through the morphological centre of the crystal, located by means of 3-D imagery from computed X-ray tomography. The data reveal strong correlations between crystal size and concentrations of Mn, Mg and Fe (but not Ca) in garnet cores; a relationship between crystal size and isolation; rigorous cross-correlations among concentrations of Mn, Mg and Fe (but not Ca); and systematic variations in Ca concentrations as a function of crystal size and core composition that are anomalous in comparison to the behaviour of the other divalent cations. We interpret these observations as the result of thermally accelerated diffusion-controlled garnet growth, in circumstances that promoted rapid intergranular diffusion and thus rock-wide equilibration of Mn, Mg and Fe, but that prevented equilibration at similar scale for Ca because of its more sluggish intergranular diffusion. The anomalous behaviour of Ca is made evident in these garnets by the presence of sharp spikes in Ca concentration, which are demonstrably not a consequence of any simultaneous rock-wide event, such as a change in pressure, temperature, or some other intensive parameter. Instead, Ca concentrations probably reflect the local extent of reaction in the immediate vicinity of each porphyroblast. To the degree that such kinetic factors introduce departures from chemical equilibrium for Ca, thermobarometric estimates that involve grossular contents of pelitic garnet will be in error.     

博斯腾湖的水盐平衡与矿化度

博斯腾湖曾是中国内陆区最大的淡水湖，因人类活动影响约在１９６８年演变为微咸水湖。本文依据湖泊水平衡太矿化度基本原理，结合博斯滕湖实际，分析计算了该湖各个时期的水盐平衡与矿化度；经推地整理，提出了预测矿化度的计算式，经检验与实测值基本吻合。     

流体的热力学前缘研究

总结了当前国内外关于流体的热力学前缘研究领域如下：（１）流体体系的ｐ－Ｖ－Ｔ－ｘ相关系研究，主要对象是Ｈ２Ｏ－ＣＯ２－盐类多组分体系高温高压下相图的实验和理论研究。（２）矿物在流体中的溶解度及溶解后在流体中溶解类型的形式和热力学性质——平衡常数（或Ｇｉｂｂｓ自由能）及各种偏摩尔性质的研究。（３）流体热力学模型化研究，已研制出大量的计算机软件，包括多种矿物、溶解类型的热力学数据库和模拟热液平衡、矿物溶解性质、反应路径和水—岩相互作用的实用程序。（４）超临界流体的相关系和化学反应等有许多特殊的性质，对认识地球内部的演化将有重要意义。（５）新技术新方法的发展，使分析单个矿物包裹体成分变成了现实。