A Study of High-Temperature and High-Pressure Experiment of Correlativity between Deformational System of Au-Bearing Rocks and Element Adjustment

Modelling of migration and accumulation of elements Au and Ag in rocks under temperatures of 350–450°C and a confining pressure of 300 MPa and axial pressure of 100–150 MPa is conducted. It is found that the contents of gold and silver get higher in metallic sulphides such as pyrite, chalcopyrite and sphalerite as well as in quartz and muscovite, and get lower in chlorite, biotite, seriate, albite and calcite, showing that tectono-dynamics is one of the important factors for petrogenesis and metallogenesis.

An experimental study of interaction between pure water and alkaline feldspar at high temperatures and pressures

Due to the important scientific significance of the interaction between alkaline feldspar and high-temperature and high-pressure fluids. We have conducted a series of autoclave experiments of feldspar dissolution and secondary mineral precipitation in conditions of 250–500℃, 8-50 MPa, and pH = 3.0 and 5.5. Based on the interaction experiments between alkaline feldspar and fluid of high-temperatures and high-pressures, we get the main results as follows:(1) The law that people have grasped below the critical point about the influence of temperature, pressure, and pH value on the alkaline feldspar dissolution behavior is still held above the critical point.(2) Due to the experimental techniques of autoclave flip 180°—sharp quenching and based on electron microprobe analysis of mineral new formed, theoretical analysis has determined that the new altered minerals distributed on the island dissolution surface of feldspar are products of precipitation on a feldspar surface after saturation of the relative ion concentration in water fluid.

The Research Status and Major Problems of High Temperature and High Pressure Experiment on Petrogenesis and mineralization

1 Introduction In contrast,1experimental geochemistry is a young subject,but in recent years,the research on experiment of high temperature and high pressure has become an important branch in the parallel subjects of traditional mineralogy,petrology,geochemistry and geophysics.It is not only an important and essential way and window to understand geological processes in depth and geological

Experimental study on liquid immiscibility of lamprophyre-sulfide melt at high temperature and high pressure and its geological significance

With lamprophyre and pyrite from the Laowangzhai gold deposit, Yunnan Province, China, as starting materials, and at pressures from 1.5 to 3.0 GPa and temperatures from 1160 to 1560℃ , an experimental study was carried out on the liquid immiscibility of lamprophyre-sulfide melt at high temperature and ultra-high pressure in the DS-29A cubic 3600T/6-type high pressure apparatus. Results showed that the liquid immiscibility of lampro-pyre-sulfide melt in the magmatic system would happen during the early magmatic evolution (high temperature and high pressure conditions) and was controlled by temperature and pressure. The sulfide melt which was separated from the lamprophyric melt would make directional movement in the temperature and pressure field and assemble in the low-temperature and low-pressure region. Because the density of SM is higher than that of the lamprophyric melt, the former would gather together at the bottom of the magma chamber and there would exist a striking boundary between the two melts. On the other hand, the results also suggested that there would be little possibility for lampro-phyric magma to carry massive gold, and lamprophyres can't provide many of oreforming materials (Au) in the processes of gold mineralization.

Evolution Characteristics of Saturated Hydrocarbons of Enclosed Organic Matter in Carbonate Minerals in Tieling Limestone Under High Temperature and High Pressure

The enclosed organic matter chiefly releases lower carbon\|number n\|alkanes under high temperature and high pressure, while the kerogen mainly produces higher carbon\|number n\|alkanes. The residual hydrocarbons generated by both kerogen and enclosed organic matter in the Tieling limestone contain abundant tricyclic terpanes, pentacyclic triterpanes and steranes, but the contents of tetracyclic terpanes and 25\|norhopane are lower. The residual enclosed organic matter shows the same distribution characteristics of n\|alkanes, steranes and terpanes as that of the original bitumen A, i.e., the higher contents of triterpanes and tetracyclic terpanes, the higher ratios of 25\|norhopanes over regular hopanes and markedly degraded steranes. By comparing the residual hydrocarbon, residual enclosed organic matter and original enclosed organic matter, it can be concluded that steranes and terpanes in the residual hydrocarbons are produced mainly by the kerogen and subordinately by the residual enclosed organic matter, the steranes and terpanes do not enter into the residual enclosed organic matter, and the thermal evolution of the residual enclosed organic matter maintains its unique character. Furthermore, pressure retards the pyrolysis of higher carbon\|number alkanes and influences the isomerization ratios of C\-\{29\}\|steranes, making 20S/(20S+20R) lower under the higher pressure than that under lower pressure. Higher pressure retards the thermal evolution of organic matter.

Compressional elastic wave velocities of serpentinized pyroxenite at high pressures and high temperatures and its geological significance

Center for Analysis and Prediction, China Seismological Bureau, Beijing 100036, China 2) Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China

Quantitative temperature imaging at elevated pressures and in a confined space with CH4/air laminar flames by filtered Rayleigh scattering

Laminar methane/air premixed flames at different pressures in a newly developed high-pressure laminar burner are studied through Cantera simulation and filtered Rayleigh scattering(FRS).Different gas component fractions are obtained through the detailed numerical simulations.And this approach can be used to correct the FRS images of large variations in a Rayleigh cross section in different flame regimes.The temperature distribution above the flat burner is then presented without stray light interference from soot and wall reflection.Results also show that the extent of agreement with the single point measurement by the thermocouple is<6%.Finally,this study concludes that the relative uncertainty of the presented filtered Rayleigh scattering diagnostics is estimated to be below 10%in single-shot imaging.

Molecular Dynamics Simulation of MgO Melting at High Pressure

Molecular dynamics simulation was used to study the melting of MgO at high pressures. The melting temperature of MgO was accurately obtained at elevated temperature and high pressure after corrections based on the modern theory of melting. The calculated melting curve was compared with the available experimental data and other theoretical results at the pressure range of 0-135 GPa. The corrected melting temperature of MgO is in good agreement with the results from Lindemann melting equation and the two- phase simulated results below 15 GPa.

极端条件下含能材料的模拟研究思考

含能材料在军事、民用和航天等领域具有广泛应用,极端条件下其物理化学性质会发生显著变化。通过模拟研究预测和优化含能材料性能具有重要意义,包括性能预测、优化设计、安全评估、成本效率控制等。为此,综述了极端条件下含能材料的研究背景、基本性质、模拟研究方法及进展、关键问题以及相关实验研究进展。其中,详细介绍了量子力学、分子动力学、蒙特卡罗和有限元等模拟方法及其研究进展,阐述了高压、高温、激光作用和界面效应等极端条件下模拟研究的关键问题,并列举了含能材料在撞击感度、化学释能规律、3D打印、绿色电合成、爆轰机理和超高含能材料合成等方面的实验研究进展。通过遴选代表性研究,展示了模拟研究在实际问题中的应用和解决方案。同时,介绍了一些最新研究成果,以反映该领域的最新进展和未来趋势。此外,详细讨论了跨学科研究的实现方式以及含能材料在极端条件下的安全性问题,包括可能的风险和预防措施。

Experimental study of the electrical conductivity of hydrous minerals in the crust and the mantle under high pressure and high temperature

Hydrous minerals are important water carriers in the crust and the mantle, especially in the subduction zone. With the recent development of the experimental technique, studies of the electrical conductivity of hydrous silicate minerals under controlled temperature, pressure and oxygen fugacity, have helped to constrain the water distribution in the Earth's interior. This paper introduces high pressure and temperature experimental study of electrical conductivity measurement of hydrous minerals such as serpentine, talc, brucite, phase A, super hydrous phase B and phase D, and assesses the data quality of the above minerals. The dehydration effect and the pressure effect on the bulk conductivity of the hydrous minerals are specifically emphasized. The conduction mechanism of hydrous minerals and the electrical structure of the subduction zone are discussed based on the available conductivity data. Finally, the potential research fields of the electrical conductivity of hydrous minerals is presented.

Genesis of granulite in Himalayan lower crust:Evidence from experimental study at high temperature and high pressure

Here we present an insight into the genesis of Himalayan granulitic lower crust based on the experimental studies on the dehydration melting of natural biotite-plagioclase gneiss performed at the temperatures of 770-980°C and the pressures of 1.0-1.4 GPa. The experiments produce peraluminous granitic melt and residual phase assemblage (Pl+Qz+Gat+Bio+Opx±Cpx+Ilm/Rut±Kfs). The residual mineral assemblage is similar to those of granu-lites observed at the eastern and western Himalayan syntax-ises, and the chemical compositions of characteristic minerals-garnet and pyroxene in the residual phase and the granu-lite are identical. Additionally, the modeled wave velocities of the residual phase assemblage are comparable well with those of the top part of lower crust beneath Himalayas. Hence, we suggest that (1) the top part of lower crust beneath Himalayas is probably made up of garnet-bearing intermediate granulite; (2) the formations of granulite and leucogranites in Himalayas are interrelated as the

Do lamprophyric magma carry gold?——Evidence from high temperature and ultrahigh pressure experiments

By taking lamprophyres in the Laowangzhai gold orefield, Yunnan Province, as starting materials, the melting experiments of lamprophyre + gold have been conducted under 1.5 and 3.0 GPa in a DS-29A cubic-type 3 600 t ultrahigh-pressure apparatus. The experimental results showed that gold powder (less than 0.045 mm) which even contributed in the samples be-

Possible seismic reflector in the lower crust: Evidence from fabrics and experiments of seismic velocity on layered gabbro at high temperature and high pressure

Lattice preferred orientations (LPO) of plagioclase and augite are measured on layered gabbro from the Panxi region, Sichuan Province. The LPO concentration [010] of plagioclase and [100] of augite are perpendicular to the foliation, which indicates a kind of growth fabric associated with crystallizing habits of minerals when the magma is solidifying under the compaction. Calculated seismic velocities based on LPO data of minerals give rise to rather strong anisotropy 5.81% and 5.54% for compressional seismic wave (Vp) and shear seismic wave (Vs), respectively. The experiments at high temperature and high pressure show that the P-wave velocity of layered gabbro is 6.44-6.97 km/s with the maximum Vp anisotropy 5.22% and the Poisson's ratio is between 0.28-0.31. According to the comparison of fabrics with seismic velocities of layered gabbro, it is uggested that the large-scale layered intrusive body or the similar layered geological body may exist in the lower crust of this area. Such a layered intrusive body which has strong seismic anisotropy may be the seismic reflector in the lower crust.

Mixing processes and patterns of fluids in alkane-CO_(2)-water systems under high temperature and high pressure——Microscopic visual physical thermal simulations and molecular dynamics simulations

Various types of geofluids exist in deep and ultra-deep layers in petroliferous basins.The geofluids are much more active under high-temperature and high-pressure(HTHP)conditions,but their properties are unclear.We simulated the mixing of different fluids in CH_(4)/C_(3)H_(8)/C_(6)H_(14)/C_(8)H_(18)-water systems and C_(6)H_(14)/C_(8)H_(18)-CO_(2)-H_(2)O systems at temperatures of 25℃ to 425℃ and pressures of 5 MPa to 105 MPa,using an in-situ micron quartz capillary tube thermal simulation system and molecular dynamics numerical simulation software.The mixing processes,patterns,and mechanisms of various fluids were analyzed at microscale under increasing temperature and pressure conditions.The results show that the miscibility of fluids in the different alkane-H_(2)O and alkane-CO_(2)-H_(2)O systems is not instantaneous,but the miscibility degree between different fluid phases increases as the temperature and pressure rise during the experiments.The physical thermal experiments(PTEs)show that the mixing process can be divided into three stages:initial miscibility,segmented dynamic miscibility,and complete miscibility.The molecular dynamics numerical simulations(MDNSs)indicate that the mixing process of fluids in the alkane-H_(2)O and alkane CO_(2)-H_(2)O systems can be divided into seven and eight stages,respectively.The carbon number affects the miscibility of alkanes and water,and the temperature and pressure required to reach the same miscibility stage with water increase with the carbon number(C_(3)H_(8),C_(6)H_(14),CH_(4),C_(8)H_(18)).CO_(2) has a critical bridge role in the miscibility of alkanes and water,and its presence significantly reduces the temperatures required to reach the initial,dynamic,and complete miscibility of alkanes and water.The results are of great significance for analyzing and understanding the miscibility of geofluids in deep and ultra-deep HTHP systems.

Experimental study of the metamorphic reaction involving melt under high temperature and high pressure

High P_T experiment with natural massive rock sample of garnet biotite plagioclase gneiss indicates that the metamorphic reaction involving melt (reaction between relic mineral phase and melt) is the most important reaction in granulite_facies metamorphism and accompanies anatexis process.

SiO_2 Solubility in Rutile at High Temperature and High Pressure

Silicon-bearing rutile has been found in chromitite from the Luobusa （罗布莎） ophiolite, Tibet. However, the extent of SiO2 solubility in rutile and the nature of its origin are still unclear. At high pressure, SiO2 takes a rutile structure with Si in 6-fold coordination. Thus, high pressures may enhance its solubility in rutile because of possible isovalent exchange in the octahedral site. In this study, we report new experimental results on SiO2 solubility in rutile up to 23 GPa and 2 000℃. Starting materials were mixtures of powdered pure rutile and pure quartz, with compositions of （Ti0.5Si0.5）O2, （Ti0.93Si0.07）O2, and （Ti0.75Si0.25）O2. The mixtures were loaded into either platinum capsules （for a 10/5 assembly） or rhenium capsules （for an 8/3 assembly）. The experiments were carried out using multi-anvil high-pressure apparatus with a rhenium resistance heater. Sample temperatures were measured with a W5%Re-W26%Re thermocouple and were controlled within ±1 ℃ of the set temperature. TiO2-rich and SiO2-rich phases were produced in all the quenched samples. Microprobe analyses of the phases show that the solubility of SiO2 in rutile increases with increasing pressure, from 1.5 wt.% SiO2 at 10 GPa to 3.8 wt.% SiO2 at 23 GPa at a temperature of 1 800 ℃. The solubility also increases with increasing temperature from 0.5 wt.% SiO2 at 1 500 ℃ to 4.5 wt.% SiO2 at 2 000 ℃ at a pressure of 18 GPa. On the other hand, the solubility of TiO2 in coesite or stishovite is very limited, with an average of 0.6 wt.% TiO2 over the experimental P-T ranges. Temperature has a much larger effect on the solubility of SiO2 in ruffle than pressure. At high pressure, the melting point of SiO2 is definitely higher than that of TiO2 and the eutectic point moves towards SiO2 in the TiO2-SiO2 system. Lower oxygen fugacity decreases the solubility of SiO2 in ruffle, whereas water has little effect on the solubility. Our experimental data are extremely useful for determining the depth of origin of the SiO2-bearing rutfle found in nature.

Upper Limit for Rheological Strength of Crust in Continental Subduction Zone:Constraints Imposed by Laboratory Experiments

The transitional pressure of quartz coesite under the differential stress and highly strained conditions is far from the pressure of the stable field under the static pressure. Therefore, the effect of the differential stress should be considered when the depth of petrogenesis is estimated about ultrahigh pressure metamorphic (UHPM) rocks. The rheological strength of typical ultrahigh pressure rocks in continental subduction zone was derived from the results of the laboratory experiments. The results indicate the following three points. (1) The rheological strength of gabbro, similar to that of eclogite, is smaller than that of clinopyroxenite on the same condition. (2) The calculated strength of rocks (gabbro, eclogite and clinopyroxenite) related to UHPM decreases by nearly one order of magnitude with the temperature rising by 100 ℃ in the range between 600 and 900 ℃. The calculated strength is far greater than the faulting strength of rocks at 600 ℃, and is in several hundred to more than one thousand mega pascals at 700-800 ℃, which suggests that those rocks are located in the brittle deformation region at 600 ℃, but are in the semi brittle to plastic deformation region at 700-800 ℃. Obviously, the 700 ℃ is a brittle plastic transition boundary. (3) The calculated rheological strength in the localized deformation zone on a higher strain rate condition (1.6×10 -12 s -l ) is 2-5 times more than that in the distributed deformation zone on a lower strain rate condition (1.6×10 -14 s -1 ). The average rheological stress (1 600 MPa) at the strain rate of 10 -12 s -1 stands for the ultimate differential stress of UHPM rocks in the semi brittle flow field, and the average rheological stress (550-950 MPa) at the strain rate of l0 -14 - 10 -13 s -l stands for the ultimate differential stress of UHPM rocks in the plastic flow field, suggesting that the depth for the formation of UHPM rocks is more than 20-60 km below the depth estimated under static pressure condition due to the effect of the differential stress.

Partial Melting and Its Implications for Understanding the Seismic Velocity Structure within the Southern Tibetan Crust

In order to constrain the crustal wave velocity structure in the southernTibetan crust and provide insight into the contribution of crustal composition, geothermal gradientand partial melting to the velocity structure, which is characterized by low average crustalvelocities and widespread presence of low-velocity zone(s), the authors model the crustal velocityand density as functions of depth corresponding to various heat flow values in light of velocitymeasurements at high temperature and high pressure. The modeled velocity and density are regarded ascomparison standards. The comparison of the standards with seismic observations in southern Tibetimplies that the predominantly felsic composition at high heat flow cannot explain the observedvelocity structure there. Hence, the authors are in favor of attributing low average crustalvelocities and low-velocity zone(s) observed in southern Tibet mainly to partial melting. Modelingbased on the experimental results suggests that a melting percentage of 7-12 could account for thelow-velocity zone(s).

An experimental study of phase transformations in olivine under pressure and temperature conditions corresponding to the mantle transition zone

High-pressure polymorphs of olivine (wadsleyite and ringwoodite) are major minerals in the mantle transition zone (MTZ).Phase transformations in olivine are important for a series of geodynamic problems such as the mineralogical and evolutionary history of the mantle,mantle convection patterns,and deep focus earthquakes in subduction zones.In this study,we examine phase transformations in olivine with two compositions,namely Mg 2 SiO 4 (Fo 100) and (Mg 0.9 Fe 0.1) 2 SiO 4 (Fo 90),at pressures between 14.1 and 20 GPa and a constant temperature of 1400°C,using the newly installed multi-anvil system at the Laboratory for Studies of the Earth's Deep Interior (SEDI),China University of Geosciences (Wuhan).At 14.1 GPa,Fo 90 transformed completely into the wadsleyite structure (β),while Fo 100 remained as olivine (α).Between 14.8 and 15.6 GPa,both Fo 100 and Fo 90 transformed into the wadsleyite structure.Wadsleyite crystals were identified by two characteristic Raman peaks between 722 and 723 and 917 and 919 cm 1.They exhibit a bimodal grain size distribution:large-crystals with average grain sizes greater than 100 μm and microcrystals less than 10 μm.The population of microcrystals increased with pressure,apparently due to the increase in over-pressure (the difference between the experimental pressure condition and the equilibrium transformation pressure at 1400°C),which promotes nucleation and retards grain growth.All run charges contained large numbers of wadsleyite microcrystals,because of the low activation energy of the nucleation process.The experimentally observed microstructure may shed light on the morphology of wadsleyite observed in shocked meteorites.At 19.5 GPa,wadsleyite coexisted with ringwoodite (γ) in Fo 100,but was absent in Fo 90.At 20 GPa,both samples transformed completely into ringwoodite,which was characterized by the 798 and 840 cm 1 Raman lines.Ringwoodite crystals are euhedral grains (average grain size 10-20 μm),with well-developed triple junctions.The complex upper mantle structure in eastern China determined from seismological studies cannot be explained by the simple transformation sequence of the olivine system alone.Phase transformations in other pyroxene-normative components (including pyroxenes and garnets) and the interaction of these components with olivine may be responsible for the complex structure.High-pressure and high-temperature experimental studies on complex systems (e.g.olivine-pyroxene),combined with data from geophysical exploration,may help in establishing a more realistic geological-petrological model for eastern China and further our understanding of the possible physical mechanisms that are responsible for the complex structure.Such studies will have profound implications for understanding the dynamic processes in the deep Earth interior.

黏温黏压下径向柱塞泵滑靴副温度分布与泄漏量分析

针对高压大排量径向柱塞泵滑靴副摩擦失效和泄漏问题,以XDP1000型径向柱塞泵为例,对滑靴副温度分布与泄漏量进行了流场仿真和数值计算。首先,根据滑靴柱塞组件运动学特性分析,求解了滑靴偏转角变化规律,并通过建立滑靴副不同通道流量计算公式的方式,建立了滑靴副静压支承特性方程;然后,建立了滑靴副泄漏功率损失和摩擦功率损失模型,求解了滑靴副最佳油膜厚度,并分析了最佳油膜厚度的变化规律;最后,在考虑了油液黏温黏压特性的基础上,通过流场数值计算的方式,研究了滑靴副温度分布与泄漏量随径向柱塞泵工况参数的变化规律。研究结果表明:额定工况下,滑靴副最佳油膜厚度值约为14μm,滑靴副最佳油膜厚度值随着转子转角的增大而增大,随着工作压力和温度的增大而减小;滑靴运动方向侧油膜温度较另一侧高13 K,滑靴副温度值基本不受工作压力的影响,而随着转速的增大而升高;滑靴副阻尼孔泄漏量较滑靴边界泄漏量大0.02 kg/s,而且泄漏量随着压力、转速和油液温度的增大而增大。该研究结论可为高压大排量径向柱塞泵滑靴副设计及优化提供参考。