西阿尔卑斯Dora Maira地块含柯石英白片岩的稳定同位素地球化学与相平衡

用氧同位素温度计测定了西阿尔卑斯ＤｏｒａＭａｉｒａ地块含柯石英—镁铝榴石白片岩的峰期变质温度。石英（柯石英较变后）的δ￣（１８）Ｏ（８．１‰～８．６‰，ｎ＝６），多硅白云母的（６．２‰～６．４‰，ｎ＝３）、蓝晶石的（６．１‰，ｎ＝２）、石榴石的（５．５‰～５．８‰，ｎ＝９）、ｅｌｌｅｎｂｅｒｇｅｒｉｔｅ的（６；３‰，ｎ＝１）和金红石的（３。３‰～３．６‰，ｎ＝３）δ￣（１８）Ｏ（ＳＭＯＷ）值反映了同位素平衡。以石英—石榴石—金红石分馏为基础测定的温度为７００～７５０℃。以对压力敏感的反应：镁铝榴石＋朽石英＝蓝晶石十顽火辉石为依据确定的最小压力为３．１～３．２ＧＰａ。为了通过对温度敏感的脱水反应：滑石十蓝晶石＝镁铝榴石十柯石英十水，来稳定镁铝榴石和柯石英，在７００～７５０℃时，α（Ｈ＿２Ｏ）必须减小到０．４～０。７５。当镁铝榴石在ｘ（ＣＯ＿２）＞０．０２（Ｔ＝７５０℃，Ｐ＝３．０ＧＰａ）不稳定时，α（Ｈ＿２Ｏ）的减少不会是由于ＣＯ＿２的稀释所引起的。当缺乏较多的外来流体稀释剂（即ＣＨ＿４或Ｎ＿２时，就需要有熔体相）。在α（Ｈ＿２Ｏ）＝１．Ｏ时，花岗岩的固相线温度为６８０℃／３．０ＧＰａ，在α（Ｈ＿２Ｏ）＝０．     

山东胶南隆起长英质岩石超高压高压岩石特征及其P—T演化

胶南隆起含榴辉岩高压变质带为大别超高压带的东延部分。超高压变质作用的主要矿物共生组合为Ｇｒｔ＋Ｋｙ＋Ｒｕｔ＋Ｊｄ＋Ｑ；Ｓｐ＋Ｚｏ＋Ａｂ±Ｇｒｔ±Ｏｍｐ；变质作用的温压条件为Ｔ＝６００～７００℃，Ｐ＝２３～２６ＧＰａ。超高压岩石及高压岩石均经历了两期退变质作用，且具有相似的顺时钟Ｐ—Ｔ演化轨迹。     

山东胶南隆起长英质岩石超高压高压岩石特征及其P—T演化

胶南隆起含榴辉石高压变质带为大别超高压带的东延部分，超高压变质作用的主要矿物共生组合为Ｇｒｔ＋Ｋｙ＋Ｒｕｔ＋Ｊｄ＋Ｑ；Ｓｐ＋Ｚｏ＋Ａｂ±Ｇｒｔ±Ｏｍｐ；变质作用的温压条件为Ｔ＝６００～７００℃，Ｐ＝２．３～２．６ＧＰａ。超高压岩石及高压岩石均经历了两期退变质作用，且具有相似的顺时钟Ｐ－Ｔ演化轨迹。     

热液体系中Si的络合作用

在不同温度、ＰＨ和硅浓度条件下,实验标定了Ａｕ－ＳｉＯ以及Ｓｎ－ＳｉＯ２之间的络合反应：Ａｕ＾＋＋Ｈ３ＳｉＯ４＾－之间的络合反应：Ａｕ＾＋＋Ｈ４ＳｉＯ＝ＡｕＨ３ＳｉＯ４ ｌｇＫ＝－１．６５４３６＋９６１１．２１／Ｔ;Ｓｎ＾４＋＋４Ｈ３ＳｉＯ４＾－＝Ｓｎ（Ｈ３ＳｉＯ４）４;ｌｇＫ２００ｃ＝４２．７３。通过与Ａｕ－Ｃｌ、Ａｕ－ＨＳ以及Ｓｎ－ＯＨ络合物迁移能力的比较,表明在具地质意义的Ｐ睡ＥＨ条件下,Ａ     

大别山榴辉岩（牌楼）P－T－t轨迹

本文重点研究了大别山潜山，牌楼地区榴辉岩Ｐ－Ｔ－ｔ轨迹，探讨了大别山地区榴辉岩成因，认为榴辉岩原岩主要是碱性玄武岩，少部分洋脊拉斑玄武岩岩浆早期结晶分异堆晶岩及部分钙质沉积岩。它们在华北与杨子板块碰撞时（２６０±３０Ｍａ），地壳向下俯冲到４０－６０ｋｍ处，温度５５０°－８３０°Ｃ，压力１．１－２．１ＧＰａ的条件下形成的。在构造抬升过程中，榴辉岩产生了角闪岩相、绿片岩相退变质作用，角闪岩相温压条件：４６０°－５７０℃，０．４－０．７ＧＰａ。流体包裹体研究表明：流体包体成分主要为ＮａＣｌ－Ｈ＿２Ｏ，Ｈ＿２Ｏ，ＮａＣｌ－ＣＯ＿２－Ｈ＿２Ｏ体系，变质作用过程从早至晚由氧化向还原环境转化。熔融包体的发现表明：榴辉岩形成具有局部深熔作用。从榴辉岩产状、岩石化学、地球化学特征表明本地区榴辉岩不是一种成因，同时具有Ｂ类、Ｃ类榴辉岩特征。     

胶东早元古代荆山群富铝片麻岩中矿物共生的P—T—X关系及其演化

根据显微构造和矿物微区化学成分的详细研究,确定了胶东早元古代荆山群富铝片麻岩中存在平衡组合Ｇｒｔ－Ｃｒｄ－Ｂｔ－Ｓｉｌ－Ｋｆｓ－Ｐｌ－Ｑｔｚ,反映变质峰期Ｇｒｔ＋Ｓｉｌ＋Ｑｔｚ→Ｃｒｄ,Ｂｔ＋Ｓｉｌ＋Ｑｔｚ→Ｇｒｔ＋Ｃｒｄ＋Ｋｆｓ＋Ｈ２Ｏ和Ｐｌ（Ａｎ）→Ｇｒｔ（Ｇｒｓ）＋Ｓｉｌ＋Ｑｔｚ①等转换反应和Ｆｅ－Ｍｇ交换反应均基本保持平衡状态。实验资料和地质温压计估算确定其峰期Ｐ－Ｔ－Ｘ关系：Ｐ为０．６０～０．７０ＧＰａ,Ｔ为７００℃～７５０℃,ＸＧｒｔＭｇ为０．２１～０．２６,ＸＣｒｔＣａ为０．０４４～０．０５３,ＸＣｒｄＭｇ为０．６５～０．７２,ＸＢｔＭｇ为０．５０～０．５７,ＸＰｌＡｎ为０．２８５～０．３８８。但Ｇｒｔ、Ｂｔ和Ｐｌ又都有明显的微区成分变化,反映峰期后降温过程各种交换反应的效应,其封闭温度在５００℃～６００℃之间,压力为０．４０～０．５０ＧＰａ。研究确立逆时针的ＰＴｔ轨迹,其样式反映早元古代陆缘壳内拗陷带的闭合过程。     

流动CO2—H2O系统中方解石溶解动力学机制：扩散边界层效应和CO2转？…

利用旋转盘实验装置和高分子生物催化剂技术,笔者研究了流动ＣＯ２－Ｈ２Ｏ系统中方解石溶解动力学及其控制机制。实验发现,方解石的溶解既受到固－液界面间扩散边界层（ＤＢＬ）的控制,还受到扩散边界层内ＣＯ２慢速转换反应（ＣＯ２＋Ｈ２Ｏ←→Ｈ＾＋＋ＨＣＯ＾）的控制。然而,高ＣＯ２分压（Ｐｃｏ２〉０．０１ａｔｍ）时,溶解主要为ＣＯ２慢速转换控制,而低ＣＯ２分压（Ｐｃｏ２〈０．０１ａｔｍ）时,溶解主要为扩散为边     

大别山北部石榴二辉麻粒岩变质结构特征

通过对大别山北部石榴二辉麻粒岩中的变质结构及变质反应特征的研究,认为石榴二辉麻粒岩在变质作用过程中,经历了四个主要的变质演化作用阶段：（１）Ｓ１阶段以早期的残留矿物,并呈包体的形式产于石榴石中为特征,以Ｃｐｘ＋Ｑ（Ｃｓ）＋Ｒｕ＋Ｇｔ组合为代表,Ｔ＝６１２～７５０℃,表明石榴二辉麻粒岩曾经历过榴辉岩相阶段的变质作用;（２）Ｓ２阶段是以Ｏｐｘ＋Ｃｐｘ＋Ｇｔ＋Ａｍｐ＋Ｑ＋Ｔｉ＋Ｍｔ矿物组合为牲,其相应的Ｔ＝８３７～８８７℃,Ｐ＝１．０３～０．９５Ｇｐａ,此时的变质条件为麻粒岩相;（３）Ｓ３阶段,矿物组合为Ｃｐｘ＋Ｇｔ＋Ａｍｐ＋Ｐｌ＋Ｍｔ,Ｔ＝５３０～６６０℃,Ｐ＝０．８５～０．９５Ｇｐａ,此时的温故知新压条件代表岩石已经进入了角闪岩相阶段;和（４）晚期的低角闪岩相阶段Ｓ４,其形成的温压条件为Ｔ＝４９５℃,Ｐ＝０．５６～０．７０Ｇｐａ。     

高温高压模拟实验气态产物碳同位素演化特征

对泥炭、褐煤样品进行了高压（０．１～２ＧＰａ）、高温（２００～８００℃）模拟实验,并用微量气体同位素测定系统（ＧＣ－Ｃ－ＭＳ）测定了气态产物的碳同位素值。在４００℃的温度条件下,乙烷、丙烷、正丁烷碳同位素值有随压力升高而变重的趋势,并出现了碳同位素局部反序的特征（δ＾１３Ｃ２〉δ＾１３Ｃ３）;在６００℃、１ＧＰａ和１．５ＧＰａ的温压条件下,甲烷和乙烷的δ＾１３（ＰＤＢ）值偏重,分别约为－１５．０‰     

晋蒙交界孔兹岩系熔体参与变质反应的结构特征及其动力学意义

晋蒙交界孔兹岩系变质反应结构与矿物相转变机制研究结果表明,在麻粒岩相变质及其与之相伴随的重熔作用过程中,存在一类特殊的有熔体参与的变质反应,即未熔矿物与熔体之间的反应。结合天然块状岩石高温高压实验,确定研究区孔兹岩系熔体参与变质反应如下：①２Ｇｔ＋（９ＳｉＯ２＋４Ａｌ２Ｏ３）熔体＝３Ｃｒｄ;②Ｇｔ＋（２ＳｉＯ２＋２Ａｌ２Ｏ３）熔体＝Ｓｐ＋Ｃｒｄ;③２Ｇｔ＋（３ＳｉＯ２）熔体＝２Ｏｐｘ＋Ｃｒｄ;④１４Ｇｔ＋（２５ＳｉＯ２＋４Ｈ２Ｏ）熔体＝４Ｃｕｍ＋７Ｃｒｄ。这类熔体参与变质反应不仅受控于温压条件,而且与寄主岩石脱水熔融、长英质矿物部分熔融存在密切成因关系。该项理论与实验研究对于深化变质反应理论、探讨孔兹岩系矿物相转变成因机制及其动力学过程有着重要的意义。     

Perturbation theory based equation of state for polar molecular fluids: I. Pure fluids

Based on the thermodynamic perturbation theory an equation of state (EOS) for molecular fluids has been formulated which can be used for many fluid species in geological systems. The EOS takes into account four substance specific parameters. These are the molecular dipole moment, the molar polarizability and the two parameters of the Lennard-Jones potential. For many fluids these parameters can be evaluated directly or indirectly from experimental measurements. In the absence of direct experimental determinations, as a first approximation, for a pure fluid the parameters of the Lennard-Jones potential can be evaluated using the critical temperature and the critical density if for polar molecules in addition the dipole moment is known with reasonable accuracy. The EOS with its model potential has the appropriate asymptotic behaviour at high pressures and temperatures and can be used to calculate both vapor-liquid equilibria and thermodynamic properties of single phase fluids up to at least 10 GPa and 2000 K. Currently, parameters for 98 inorganic and organic compounds are available. In this article the EOS for pure fluids is presented. In a further communication the EOS is extended to fluid mixtures (Churakov and Gottschalk, 2003).     

宽广温压范围内纯流体pVT性质的预测

一个具有 1 9个参数的半经验状态方程 ,可以很容易地转化为关于体积的多项式方程 ,应用起来十分方便。对于气体和超临界流体 ,该方程可以在很宽的温压范围内保持较高的精度。用该方程计算 H2 O、CO2 、CH4、H2 、CO、O2 等流体的 p VT关系 ,结果令人满意。在从常温常压直到 4 0 0 0～ 50 0 0 K和 90～ 60 0 GPa的范围内 ,预测的体积误差为 :平均偏差小于 1 % ,最大偏差小于 6% ,标准偏差小于 1 .5%。     

A general equation of state for supercritical fluid mixtures and molecular dynamics simulation of mixture PVTX properties

A general Equation of State (EOS), which we previously developed for pure nonpolar systems, is extended to polar systems such as water and to mixtures in this study. This EOS contains only two parameters for each pure component and two additional parameters for each binary mixture (no higher order parameters are needed for more complicated mixture systems). The two mixing parameters can be eliminated for nonaqueous mixtures with a slight loss of accuracy in both total mole volume and in excess volume (or nonideal mixing). Comparison with a large amount of experimental PVTX data in pure systems (including H₂O) and in the mixtures, H₂O-CO₂, CO₂-N₂, CH₄-CO₂, and N₂-CO₂-CH₄ results in an average error of 1.6% in density. Comparison with commonly used EOS for supercritical fluids shows that the EOS of this study covers far more T-P-X space with higher accuracy. We believe that it is accurate from supercritical temperature to 2000 K and from 0 to 25,000 bar or higher with an average error in density of less than 2% for both pure members and mixtures in the system H₂O-CO₂-CH₄-N₂-CO-H₂-O₂-H₂S-Ar and possibly with additional gases. Comparison with the published simulated data suggests that this EOS is approximately correct up to 300,000 bar and 2800 K.We also simulated the PVTX properties of a number of supercritical fluid mixtures using molecular dynamics (MD) simulation. These results and those of other authors are well predicted by the EOS of this study.     

Equation of state of the H2O, CO2, and H2O-CO2 systems up to 10 GPa and 2573.15 K: Molecular dynamics simulations with ab initio potential surface

Based on our previous development of the molecular interaction potential for pure H₂O and CO₂ [Zhang, Z.G., Duan, Z.H. 2005a. Isothermal-isobaric molecular dynamics simulations of the PVT properties of water over wide range of temperatures and pressures. Phys. Earth Planet Interiors149, 335-354; Zhang, Z.G., Duan, Z.H. 2005b. An optimized molecular potential for carbon dioxide. J. Chem. Phys.122, 214507] and the ab initio potential surface across CO₂-H₂O molecules constructed in this study, we carried out more than one thousand molecular dynamics simulations of the PVTx properties of the CO₂-H₂O mixtures in the temperature-pressure range from 673.15 to 2573.15 K up to 10.0 GPa. Comparison with extensive experimental PVTx data indicates that the simulated results generally agree with experimental data within 2% in density, equivalent to experimental uncertainty. Even the data under the highest experimental temperature-pressure conditions (up to 1673 K and 1.94 GPa) are well predicted with the agreement within 1.0% in density, indicating that the high accuracy of the simulation is well retained as the temperature and pressure increase. The consistent and stable predictability of the simulation from low to high temperature-pressure and the fact that the molecular dynamics simulation resort to no experimental data but to ab initio molecular potential makes us convinced that the simulation results should be reliable up to at least 2573 K and 10 GPa with errors less than 2% in density. In order to integrate all the simulation results of this study and previous studies [Zhang and Duan, 2005a, 2005b] and the experimental data for the calculation of volumetric properties (volume, density, and excess volume), heat properties, and chemical properties (fugacity, activity, and possibly supercritical phase separation), an equation of state (EOS) is laboriously developed for the CO₂, H₂O, and CO₂-H₂O systems. This EOS reproduces all the experimental and simulated data covering a wide temperature and pressure range from 673.15 to 2573.15 K and from 0 to 10.0 GPa within experimental or simulation uncertainty.     

An improved and extended internally consistent thermodynamic dataset for phases of petrological interest,involving a new equation of state for solids

The thermodynamic properties of 254 end‐members, including 210 mineral end‐members, 18 silicate liquid end‐members and 26 aqueous fluid species are presented in a revised and updated internally consistent thermodynamic data set. The PVT properties of the data set phases are now based on a modified Tait equation of state (EOS) for the solids and the Pitzer & Sterner (1995) equation for gaseous components. Thermal expansion and compressibility are linked within the modified Tait EOS (TEOS) by a thermal pressure formulation using an Einstein temperature to model the temperature dependence of both the thermal expansion and bulk modulus in a consistent way. The new EOS has led to improved fitting of the phase equilibrium experiments. Many new end‐members have been added, including several deep mantle phases and, for the first time, sulphur‐bearing minerals. Silicate liquid end‐members are in good agreement with both phase equilibrium experiments and measured heat of melting. The new dataset considerably enhances the capabilities for thermodynamic calculation on rocks, melts and aqueous fluids under crustal to deep mantle conditions. Implementations are already available in thermocalc to take advantage of the new data set and its methodologies, as illustrated by example calculations on sapphirine‐bearing equilibria, sulphur‐bearing equilibria and calculations to 300 kbar and 2000 °C to extend to lower mantle conditions.     

Perturbation theory based equation of state for polar molecular fluids: II. Fluid mixtures

The equation of state (EOS) for 98 pure organic and inorganic fluids formulated by Churakov and Gottschalk (2003) is extended to complex fluid mixtures. For the calculation of the thermodynamic properties of mixtures, theoretical combining rules from statistical mechanics are used. These mixing rules do not involve any empirical parameters. The properties of the fluid mixtures are directly derived from those of the pure constituents. As an example we show that the EOS describes accurately the thermodynamic relations in the H₂O-CO₂ binary at high pressures and temperatures. At subcritical conditions the EOS is able to reproduce accurately the phase relations within mixtures of non-polar fluids. In particular the EOS predicts phase separations within various fluid mixtures of polar and non-polar molecules.     

Molecular dynamics simulation of the CH4 and CH4-H2O systems up to 10 GPa and 2573 K

Based on our previous study of the intermolecular potential for pure H₂O and the strict evaluation of the competitive potential models for pure CH₄ and the ab initio fitting potential surface across CH₄-H₂O molecules in this study, we carried out more than two thousand molecular dynamics simulations for the PVTx properties of pure CH₄ and the CH₄-H₂O mixtures up to 2573 K and 10 GPa. Comparison of 1941 simulations with experimental PVT data for pure CH₄ shows an average deviation of 0.96% and a maximum deviation of 2.82%. The comparison of the results of 519 simulations of the mixtures with the experimental measurements reveals that the PVTx properties of the CH₄-H₂O mixtures generally agree with the extensive experimental data with an average deviation of 0.83% and 4% in maximum, which is equivalent to the experimental uncertainty. Moreover, the maximum deviation between the experimental data and the simulation results decreases to about 2% as temperature and pressure increase, indicating that the high accuracy of the simulation is well retained in the high temperature and pressure region.After the validation of the simulation method and the intermolecular potential models, we systematically simulated the PVTx properties of this binary system from 673 K and 0.05 GPa to 2573 K and 10 GPa. In order to integrate all the simulation results and the experimental data for the calculation of thermodynamic properties, an equation of state (EOS) is developed for the CH₄-H₂O system covering 673-2573 K and 0.01-10 GPa. Isochores for compositions <4 mol% CH₄ up to 773 K and 600 MPa are also determined in this paper. The program for the EOS can be downloaded from www.geochem-model.org/programs.htm.     

An equation of state for carbon dioxide valid from zero to extreme pressures

A new form of equation of state is described with application to carbon dioxide from 215 K to T>2000 K and from zero pressure to more than 10⁵ bar (10 GPa). The equation was calibrated using properties predicted by existing formulations at low to moderate PT conditions, original experimental PVT data at higher pressures, corresponding states comparisons at higher temperatures and using shock compression data at still higher PTs. Extensive comparisons illustrating the correlation of our new EOS with available phase equilibria and volumetric data are provided. Fugacities of carbon dioxide at high pressures and temperatures predicted using our EOS are in agreement with mineral equilibria calculated from internally consistent thermodynamic data for minerals.     

Synchrotron powder diffraction study of phengite 3T from the Dora-Maira massif: P -V -T equation of state and petrological consequences

X-ray powder diffraction measurements have been carried out at ESRF (Grenoble, France) on the ID30 beamline to study the equation of state of 3T phengite (Dora-Maira massif, Italian western Alps) by a large volume cell up to P = 50 kbar and T = 1000 K. Several equations of state (EOS) models (the Vinet EOS, the Birch-Murnaghan EOS and its variants, a VT-polynomial expansion) have been used to interpolate the experimental data and discussed in the light of the results achieved. The thermoelastic properties of 3T phengite (bulk modulus, its derivatives versus pressure or temperature, bulk thermal expansion) have been obtained and an isochoric curve with slope P/T = 0.02 kbar/K has been calculated by means of the Vinet EOS. This slope value supports either the occurrence at the peak conditions (about 30 kbar and 1000 K) of an originally Mg/Si-richer and stiffer phengite or a non-isochoric P-T retrograde path. Received: 5 June 1998 / Revised, accepted: 12 December 1998     

Molecular dynamics studies of CaAl2Si2O8 liquid. Part II: Equation of state and a thermodynamic model

A thermodynamic model and equation of state (EOS) is developed from the molecular dynamics simulation experiments of Spera et al. (2009) for CaAl₂Si₂O₈ liquid over the temperature range 3500-6000 K and pressure interval 0-125 GPa. The model is constructed utilizing the isothermal Universal EOS of Vinet et al. (1986) combined with an expression for the temperature-dependence of the internal energy derived from density functional theory (Rosenfeld and Tarazona, 1998). It is demonstrated that this model is more successful at reproducing the data than the temperature-dependent Universal EOS (Vinet et al., 1987) or the volume-explicit EOS of Ghiorso (2004a). Distinct parameterizations are required to model low (<20 GPa) and high (>20 GPa) pressure regimes. This result is ascribed to the affect of liquid structure on macroscopic thermodynamic properties, specifically the interdependence of average cation-oxygen coordination number on the bulk modulus. The thermodynamic transition between the high- and low-pressure parameterizations is modeled as second order, although the nature of the transition is open to question and may well be first order or lambda-like in character.Analysis of the thermodynamic model reveals a predicted region of liquid-liquid un-mixing at low-temperatures (<1624 K) and pressures (<1.257 GPa). These pressure-temperature conditions are above the glass transition temperature but within the metastable liquid region. They represent the highest temperatures yet suggested for liquid-liquid un-mixing in a silicate bulk composition. A shock wave Hugoniot curve is calculated for comparison with the experimental data of Rigden et al. (1989) and of Asimow and Ahrens (2008). The comparison suggests that the model developed in this paper underestimates the density of the liquid by roughly 10% at pressures greater than ∼20 GPa.