贵州及邻省区与蒸发岩和油气有关的汞矿成矿物理化学条件

对区域汞矿床中辰砂及其共生的脉石矿物的同位素组成和矿物包裹体成分的研究，讨论了所论汞矿成矿的物理化学条件。结合四川、重庆等地现代卤水（黄卤、黑卤）的对比研究和分析，认为黄卤和黑卤是具有成矿潜力的封存热卤水。     

矿物包裹体研究在成因矿物学中的应用

矿物的形成与分布主要受温度、压力、介质性质等物理化学条件所制约。研究者们为了了解这些物理化学参数曾多方面进行探索。应用矿物中包裹体所包含的原始成岩成矿介质来探讨矿物形成的温度、压力、介质浓度及成分,矿物共生组合及空间分布规律、成矿物质来源等问题有着指导意义。目前地质研究者广泛应用这一手段解决成岩、     

夹皮沟金矿成矿物理—化学参数的计算

根据夹皮沟地区金矿床的围岩蚀变特征，矿物组合及载金矿物石英包裹体成分等，利用国内外研究金成矿时所得到的实验数据，推导出夹皮沟地区金矿床成矿时的某些物理化学参数。     

大水沟碲矿床成矿物理化学条件研究

本文在对大水沟碲矿床各成矿阶段矿物共生分析、成矿温度、矿液成分研究的基础上,对成矿的其它物理化学条件,如pH、f_O2、f_S2、f_Te2等作了热力学计算,并结合矿床地质资料,计算与分析了成矿过程中碲的迁移形式及富集机理。     

黄铁矿、黄铜矿的稳定性实验研究

在热液条件下,实验研究影响矿物的稳定性的主要因素、变化过程和特征以及矿物的共生组合演变,对于研究成矿作用的物理化学条件,进而探讨成矿机理,都具有重要意义,一、实验条件的选择我们过去研究资料认为,斑岩铜矿床的成矿温度主要为250～350℃.因此确定实验的温度为200～400℃,压力为50～350大气压.根据国内外对斑岩铜矿床中矿物包裹体成分的研究,成矿溶液中富含KCl、NaCl及多种重     

滇东北茂租热液型铅锌矿床矿物组合共生分异的热力学Eh—pH相图

滇东北地区广泛分布的热液型铅锌矿床具有普遍的矿物组合分带特征,研究矿床矿物组合的共生分异特征,是了解该类型矿床的成矿流体在演化过程中,成矿元素迁移和沉淀的核心问题之一,通过共生矿物的热力学Eh—pH相图可以有效的诠释成矿流体中成矿元素在迁移、沉淀过程中的物理化学条件。本文以滇东北茂租铅锌矿床为例,对滇东北热液型铅锌矿床的金属矿物共生组合在时间、空间分带特征进行热力学相图分析,选取373K、423K、473K、523K四个温度截面对金属矿物共生组合稳定存在的Eh—pH范围进行计算,相图显示成矿流体中矿物迁移、沉淀机制主要是由于成矿流体的Eh、p H值双重制约:Eh值的变化控制着硫化物沉淀的时间分带,成矿流体从深部向浅部运移,Eh值将会逐渐增大,主要矿物从黄铁矿→方铅矿→闪锌矿依次开始析出;p H值控制硫化物的空间分带,随着p H值的增大,成矿元素从离子的形式转变为硫酸盐矿物进行迁移。研究表明,控制成矿流体中硫化物迁移、沉淀的物理化学条件除了温度、压力、金属离子浓度及流体的氧硫逸度之外,流体的酸碱度及氧化还原电位同样是控制矿物组合共生分异的重要影响因素,此研究对该类型矿床的成矿流体的演化和成矿机制提供了一定的理论依据。     

矽卡岩石榴石研究现状

<正>矽卡岩矿床是在中酸性侵入体和碳酸盐类等岩石的接触带及其附近,由含矿热液交代作用而形成的热液矿床,也称为接触交代矿床,与许多金属和非金属矿床有密切关系,常见矽卡岩型Fe、Cu、W、Mo、Pb、Zn等矿床。矽卡岩矿物成分比较复杂,矿物组合及矿物自身的特征与围岩、岩浆岩及矿化条件有着密切的关系。矿物共生组合关系是矽卡岩矿床分带的重要依据。矽卡岩矿物的结构构造和化学成分,可以揭示矽卡岩形成过程中重要的物理化学信息,同时为成矿过程及成矿环境的研究提供依据。常见的矽卡岩     

锗的重要迁移形式——锗氢化物

经对锗及其氢化物的物理化学性质、有关矿床矿物流体包裹体化学成分、主要含锗矿物及锗矿物的化学成分、内生锗矿物的共生伴生矿物特征等相关问题的研讨,认为锗氢化物、锗合金氢化物是锗成矿的重要迁移形式。     

新疆齐求Ⅰ金矿床蚀变矿物与金矿化

蚀变矿物-钠长石、含镁方解石、绢云母与自然金属同一成矿阶段的产物.钠长石、含镁方解石、自然金具有成分环带,在成矿过程中,局部成矿物理化学环境的改变是造成其成分环带的主要因素之一.     

某水晶矿床成矿溶液研究及矿床成因

在某水晶矿床的普查勘探工作中，我们利用矿物包裹体对矿床成因，特别是成矿溶液来源、性质、成分、温度、盐度等问题进行了研究。通过研究使我们对矿区成矿溶液的物理化学性质以及石英脉和水晶的形成有了一些认识，现就这方面的问题试作某些粗浅的讨论。     

物相之间氧同位素分馏的高温高压实验研究

应用理论计算、实验测定和经验估计三种方法均能获取含固体矿物体系的氧同位素分馏系数,其中高温高压实验研究不仅能够得到物相之间的同位素平衡分馏系数,而且能够提供与同位素交换动力学和机理有关的信息。同位素分馏系数的实验校准方法已经由原来的两相体系（矿物Ｈ２Ｏ、矿物ＣＯ２和矿物ＣａＣＯ３）交换发展为三相体系（ＣａＣＯ３矿物流体）交换,化学合成、重结晶和矿物反应技术得到了进一步应用。本文评述了近十年来这一领域的研究进展,着重介绍了Ｈ２Ｏ、ＣＯ２和ＣａＣＯ３作为交换介质进行氧同位素分馏系数校准的技术原理和结果,探讨了热液和碳酸盐交换实验结果不一致的原因。     

H2O in metamorphism and unexpected behaviour in the preservation of metamorphic mineral assemblages

The preservation of mineral assemblages that were fluid‐present during their prograde history is primarily related to the consumption of the fluid by growth of more hydrous minerals as the retrograde history begins. The range of behaviour relating to the preservation of mineral assemblages is examined using calculated phase diagrams for fluid‐saturated conditions, contoured for the H₂O content of the mineral assemblage. At equilibrium, as a mineral assemblage crosses contours of decreasing H₂O content along a pressure–temperature path, it dehydrates, the fluid being lost from the rock. If the assemblage crosses contours of increasing H₂O content, the mineral assemblage starts to rehydrate using any fluid on its grain boundaries. When the rock has consumed its fluid, the resulting mineral assemblage is that preserved in the rock. Conditions relating to the preservation of mineral assemblages are discussed, and examples of the consequences of different pressure–temperature paths on preservation in a metapelitic and a metabasic rock composition are considered on phase diagrams calculated with thermocalc .     

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。     

Phase equilibria in the hornblende-bearing basic gneisses of the Uvete area, central Kenya

Abstract The hornblende-bearing basic gneisses in the Uvete area, central Kenya, were metamorphosed under a narrow range of P and T (6.5 ± 0.5kbar and 530 ± 40°C) of the staurolitekyanite zone in the Mozambique metamorphic belt. They show a wide variety of divariant and trivariant mineral assemblages consisting of hornblende, cumminatonite, gedrite, anthophyllite, chlorite, garnet, epidote, clinopyroxene, plagio-clase and quartz. The bulk and mineral chemistries and the graphical representation of phase relations show that each mineral assemblage approaches chemical equilibrium and defines a unique composition volume in the A'(Al + Fe³⁺− (13/7)Na)-F(Fe²⁺)-M'(Mg)-C'(Ca-(3/7)Na) tetrahedron. The composition volumes are distributed quite regularly and do not overlap each other.
The phase relations in the Uvete area are in contrast with those in the staurolite-kyanite zone amphibolites in the Mt. Cube quadrangle, Vermont. The amphibolites there contain low-variance mineral assemblages formed under different values of μ_H2O and μ_CO2. These assemblages define overlapping composition volumes in the A'-F'-M'-C'tetrahedron.
The mineral assemblages in the Uvete area are interpreted as having formed in equilibrium with fluid at a high and nearly constant μH₂O value. Such a fluid composition was externally controlled by the supply of H₂O-rich fluid expelled from the surrounding pelitic and psammitic rocks. The body size of the basic gneisses in the Uvete area (less than 400m in thickness) was small enough for the fluid to migrate completely.     

Pressure and equilibrium in deforming rocks

It is widely proposed that tectonic pressure (the difference between the mean stress and the pressure arising from a lithostatic load) is large, and has a significant influence on mineral phase equilibria in deforming metamorphic rocks. The implication/assertion is that the mean stress is equivalent to the thermodynamic pressure which characterizes mineral phase equilibria and is a measure of how the energy changes as the volume changes. We distinguish two useful thermodynamic pressures. The first is an equilibrium thermodynamic pressure, characteristic of non‐dissipative systems and related directly to equilibrium values of the chemical potentials that define stable, equilibrium phase assemblages. The second is a non‐equilibrium thermodynamic pressure characteristic of dissipative systems with zero net entropy production and related to non‐equilibrium chemical potentials that define stable non‐equilibrium phase assemblages. In many dissipative metamorphic systems discussed in the literature, the concepts of thermodynamic pressure and chemical potential are not usefully defined because the system is not at equilibrium and/or no volume change is involved in the deformation. The conclusion of this note is that the influence of tectonic pressure on phase equilibria is minor. The role of tectonic pressure is an important issue but is only relevant to phase equilibrium when an equilibrium thermodynamic pressure can be defined; in such cases, the influence of tectonic pressure is small compared to many proposals in the literature. Except for elastic deformations, the mean stress is not useful in discussing mineral phase equilibrium.     

An internally consistent thermodynamic data set for phases of petrological interest

The thermodynamic properties of 154 mineral end-members, 13 silicate liquid end-members and 22 aqueous fluid species are presented in a revised and updated data set. The use of a temperature-dependent thermal expansion and bulk modulus, and the use of high-pressure equations of state for solids and fluids, allows calculation of mineral–fluid equilibria to 100  kbar pressure or higher. A pressure-dependent Landau model for order–disorder permits extension of disordering transitions to high pressures, and, in particular, allows the alpha–beta quartz transition to be handled more satisfactorily. Several melt end-members have been included to enable calculation of simple phase equilibria and as a first stage in developing melt mixing models in NCKFMASH. The simple aqueous species density model has been extended to enable speciation calculations and mineral solubility determination involving minerals and aqueous species at high temperatures and pressures. The data set has also been improved by incorporation of many new phase equilibrium constraints, calorimetric studies and new measurements of molar volume, thermal expansion and compressibility. This has led to a significant improvement in the level of agreement with the available experimental phase equilibria, and to greater flexibility in calculation of complex mineral equilibria. It is also shown that there is very good agreement between the data set and the most recent available calorimetric data.     

Mechanical and transport constitutive models for fractures subject to dissolution and precipitation

Transient changes in the permeability of fractures in systems driven far‐from‐equilibrium are described in terms of proxy roles of stress, temperature and chemistry. The combined effects of stress and temperature are accommodated in the response of asperity bridges where mineral mass is mobilized from the bridge to the surrounding fluid. Mass balance within the fluid accommodates mineral mass either removed from the flow system by precipitation or advection, or augmented by either dissolution or advection. Where the system is hydraulically closed and initially at equilibrium, reduction in aperture driven by the effects of applied stresses and temperatures will be augmented by precipitation on the fracture walls. Where the system is open, the initial drop in aperture may continue, and accelerate, where the influent fluid is oversaturated with respect to the equilibrium mineral concentration within the fluid, or may reverse, if undersaturated. This simple zero‐dimensional model is capable of representing the intricate behavior observed in experiments where the feasibility of fracture sealing concurrent with net dissolution is observed. This zero‐order model is developed as a constitutive model capable of representing key aspects of changes in the transport parameters of the continuum response of fractured media to changes in stress, temperature and chemistry. Copyright © 2009 John Wiley & Sons, Ltd.     

Calculation of pH and mineral equilibria in hydrothermal waters with application to geothermometry and studies of boiling and dilution

Using chemical analyses and 25° pH measurements of quenched high-temperature waters, we calculate in situ pH and distribution of aqueous species at high temperature. This is accomplished by solving simultaneous mass action equations for complexes and redox equilibria and mass balance equations, on all components, including a H⁺ equation with as many as 60 terms (depending on water composition). This calculation provides accurate values for the activities of aqueous ions in a given water at high temperature, which are used to calculate an ion activity product (Q) for each of more than 100 minerals. The value of log(Q/K) for each mineral, where K is the equilibrium constant, provides a measure of proximity of the aqueous solution to equilibrium with the mineral. By plotting log Q/Kvs. T for natural waters, it is possible to determine: a) whether the water was in equilibrium with a host rock mineral assemblage, b) probable minerals in the equilibrium assemblage and c) the temperature of equilibrium. In cases where the fluid departs from equilibrium with a host rock assemblage, it is possible to determine whether this may result from boiling or dilution, and an estimate of amount of lost gas or diluting water can be determined.The calculation is illustrated by application to geothermal waters from Iceland, Broadlands, and Sulphur Bank, hot spring waters from Jemez, Yellowstone and Blackfoot Reservoir (Idaho) and fluid inclusions from the Sunnyside Mine, Colorado. It is shown that most geothermal waters approach equilibrium with a subsurface mineral assemblage at a temperature close to measured temperatures and that some hot springs also approach equilibrium with the host rock at temperatures above outlet temperatures but commonly below the Na-K-Ca temperatures. The log Q/K plots show that some discrepancies between Na-K-Ca temperatures on spring waters and actual temperatures result from a failure of alkali feldspars to equilibrate with the fluid and with each other.Calculations on Sulphur Bank fluids show that boiling probably caused cinnabar precipitation near 150°C and that the boiled fluids equilibrated with secondary minerals near 150° even though temperatures up to 185° have been measured at depth. For the fluid inclusions, the measured bubble temperatures are close to those calculated for equilibration of the fluid with the observed sulfide mineral assemblage.New estimates of stability constants for aluminum hydroxide complexes are included at the end of the paper.     

Determining the direction of contact metamorphic fluid flow: an assessment of mineralogical and stable isotope criteria

ABSTRACT One-dimensional fluid advection-dispersion models predict differences in the patterns of mineralogical and oxygen isotope resetting during up- and down-temperature metamorphic fluid flow that may, in theory, be used to determine the fluid flow direction with respect to the palaeotemperature gradient. Under equilibrium conditions, down-temperature fluid flow is predicted to produce sharp reaction fronts that separate rocks with isobarically divariant mineral assemblages. In contrast, up-temperature fluid flow may produce extensive zones of isobarically univariant mineral assemblages without sharp reaction fronts. However, during contact metamorphism, mineral reaction rates are probably relatively slow compared with fluid velocities and distended reaction fronts may also form during down-temperature fluid flow. In addition, uncertainties in the timing of fluid flow with respect to the thermal peak of metamorphism and the increase in the variance of mineral assemblages due to solid solutions introduce uncertainties in determining fluid flow directions. Equilibrium down-temperature flow of magmatic fluids in contact aureoles is also predicted to produce sharp δ¹⁸O fronts, whereas up-temperature flow of fluids derived by metamorphic devolatilization may produce gradational δ¹⁸O vs. distance profiles. However, if fluids are channelled, significant kinematic dispersion occurs, or isotopic equilibrium is not maintained, the patterns of isotopic resetting may be difficult to interpret. The one-dimensional models provide a framework in which to study fluid-rock interaction; however, when some of the complexities inherent in fluid flow systems are taken into account, they may not uniquely distinguish between up- and down-temperature fluid flow. It is probably not possible to determine the fluid flow direction using any single criterion and a range of data is required.     

Physicochemical crystallization conditions of Al-F sphene in metasomatic rocks with ore mineralization at the Berezitovoe Deposit

Al-F sphene (grothite) was found in mineralized rocks at the Berezitovoe Deposit in the Russian Far East. The paper is devoted to the mineral assemblages and composition of the mineral and its thermodynamic crystallization conditions. The average Al and F concentrations (p.f.u., microprobe data) in the grothite are 0.45 and 0.42 in sample 1374, 0.32 and 0.32 in sample 1306, and 0.35 and 0.33 in sample 96. Grothite was found in the rocks in association with chlorite, ilmenite (pyrophanite), and magnetite, and this mineral assemblage was obviously overprinted on the primary garnet-biotite assemblages. We estimated the temperature of grothite crystallization at 400–500°C. With regard for available experimental data on the mineral equilibrium between Al-F sphene, fluid, and anorthite, a tool is proposed for evaluating F concentrations in fluids by the equilibrium of Al-F sphene with plagioclase, rutile, and F-bearing aqueous fluid. Our model simulations indicate that the maximum F concentration in fluid during the crystallization of Al-F sphene richest in F at the temperatures and pressures of metasomatic rocks at the Berezitovoe deposit could reach 300–500 mg per kg of the aqueous solution. The level of F concentration in the fluid during the crystallization of Al-F sphene at the deposit is comparable with the F concentration in fluid during the development of greisens and rare-metal pegmatites, but these high F concentrations were reached only during the final evolutionary stages of the deposit.