矿物热力学数据的获取     

殷辉安 《地球科学进展》1993,8(2):33-39

简介矿物热力学数据获取方法发展现状,重点评述量热法和相平衡法的近期发展状况。  相似文献   

Peristerite compositions in quartzofeldspathic schists, Franz Josef-Fox Glacier Area, New Zealand     

RODNEY GRAPES  MASAYUKI OTSUKI 《Journal of Metamorphic Geology》1983,1(1):47-61

Plagioclase compositions vary from An_0.1–2.5 to An₃₂ with increasing grade in chlorite zone to oligoclase zone quartzofeldspathic schists, Franz Josef-Fox Glacier area, Southern Alps, New Zealand. This change is interrupted by the peristerite composition gap in rocks transitional between greenschist and amphibolite facies grade. Oligoclase (An_20-24) and albite (An_0.1–0.5) are found in biotite zone schists below the garnet isograd. With increasing grade, the plagioclase compositions outline the peristerite gap, which is asymmetric and narrows to compositions of An₁₂ and An₆ near the top of the garnet zone. In any one sample, oligoclase is the stable mineral in mica-rich layers above the garnet isograd, whereas albite and oligoclase exist in apparent textural equilibrium in adjacent quartz-plagioclase layers. The initial appearance of oligoclase in both layers results from the breakdown of epidote and possibly sphene. Carbonate is restricted to the quartz-plagioclase rich layers and probably accounts for the more sodic composition of oligoclase in these layers. The formation of more Ca-rich albite and more Na-rich oligoclase near the upper limit of the garnet zone coincides with the disappearance of carbonate and closure of the peristerite gap. Garnet appears to have only a localized effect on Ca-enrichment of plagioclase in mica-rich layers within the garnet zone. The Na-content of white mica increases sympathetically with increasing Ca-content of oligoclase and metamorphic grade. Comparison of the peristerite gap in the Franz Josef-Fox Glacier schists and schists of the same bulk composition in the Haast River area, 80 km to the S, indicates that oligoclase appears and epidote disappears at lower temperatures, and that the composition gap between coexisting albite and oligoclase is narrower in the Franz Josef-Fox Glacier area. It is suggested that a higher thermal gradient (38-40°C/km) and variations in Si/Al ordering during growth of the plagioclases between the two areas may account for these differences. In the Alpine schists the peristerite gap exists over a temperature and pressure interval of about 370-515°C and 5.5-7 kbar (550-700 MPa) P_H2O.  相似文献   

High-pressure Partial Melting of Mafic Lithologies in the Mantle   总被引：17，自引：2，他引：15  

KOGISO  T.; HIRSCHMANN  M. M.; PERTERMANN  M. 《Journal of Petrology》2004,45(12):2407-2422

We review experimental phase equilibria associated with partialmelting of mafic lithologies (pyroxenites) at high pressuresto reveal systematic relationships between bulk compositionsof pyroxenite and their melting relations. An important aspectof pyroxenite phase equilibria is the existence of the garnet–pyroxenethermal divide, defined by the enstatite–Ca-Tschermakspyroxene–diopside plane in CaO–MgO–Al₂O₃–SiO₂projections. This divide appears at pressures above 2 GPa inthe natural system where garnet and pyroxenes are the principalresidual phases in pyroxenites. Bulk compositions that resideon either side of the divide have distinct phase assemblagesfrom subsolidus to liquidus and produce distinct types of partialmelt ranging from strongly nepheline-normative to quartz-normativecompositions. Solidus and liquidus locations are little affectedby the location of natural pyroxenite compositions relativeto the thermal divide and are instead controlled chiefly bybulk alkali contents and Mg-numbers. Changes in phase volumesof residual minerals also influence partial melt compositions.If olivine is absent during partial melting, expansion of thephase volume of garnet relative to clinopyroxene with increasingpressure produces liquids with high Ca/Al and low MgO comparedwith garnet peridotite-derived partial melts. KEY WORDS: experimental petrology; mantle heterogeneity; partial melting; phase equilibrium; pyroxenite  相似文献   

三元体系K+,Mg2+/B4O2-7-H2O 25℃相关系研究          下载免费PDF全文

靳治良  孙柏  李刚  李武 《盐湖研究》2004,12(2)

对三元体系K+,Mg2+/B4O2-7-H2O25℃的溶解度进行了研究,该体系属简单共饱型,两段溶解度曲线对应于体系的两种原始组分K2B4O7·4H2O、MgB4O7·9H2O的结晶区,共饱点组成为K2B4O713 96%,MgB4O70 53%。  相似文献   

加筋路堤稳定性综合分析方法   总被引：4，自引：0，他引：4  

陈建峰  石振明  孙红 《岩土力学》2004,25(Z2):433-436

软土路基上加筋路堤的稳定性可以采用圆弧滑动极限平衡法进行分析,加筋路堤的破坏可以归纳为圆弧内加筋的破坏、圆弧外加筋的破坏以及加筋路堤的整体破坏.提出了计算加筋路堤稳定系数K的3个不同的稳定系数表达式,分别称之为圆弧内部稳定系数Kn、圆弧外部稳定系数Kw和整体稳定系数Kz,加筋路堤稳定系数K取其中的最小值.采用该方法对一加筋路堤破坏实例进行稳定性综合分析,得到的对应于最小稳定系数的滑移面与实际滑移面比较吻合.  相似文献   

柴东盆地五道梁地区航放异常特征及成因分析   总被引：2，自引：0，他引：2  

金和海 《铀矿地质》2004,20(4):235-244

本文着重分析了柴达木盆地东部五道梁地区航放异常的展布特征、异常性质、产出位置 ,异常区铀、镭含量及铀镭平衡状态。认为该航放异常系镭异常 ,具有点源、深源性质 ,与五道梁断裂密切相关  相似文献   

对矿山生态环境治理必要性的讨论   总被引：1，自引：0，他引：1  

陈桥　胡克冯军  李福来 《地质通报》2004,23(4):310-313

目前普遍认为矿山牛态环境在开采的同时必须治理，这种思维忽略了生态环境具有一定的自然适应性，即较小的扰动使生态系统有所变化，进而产生新的生态系统，新系统仍能维持良性循环。本文以生物阻抗性和自然恢复性及自然系统加大作用力效应模式为基础，提出一个新的矿业活动生态环境作用效应模式，为矿山生态环境治理的投资、政策引导等方面提供建设性的建议。  相似文献   

Influence of a low-viscosity layer between rigid inclusion and viscous matrix on inclusion rotation and matrix flow: A numerical study   总被引：1，自引：0，他引：1  

Fernando O. Marques  R. Taborda  J. Antunes 《Tectonophysics》2005,407(1-2):101-115

We have used 2-D finite element modelling to investigate the influence of a permanent low-viscosity layer between matrix and inclusion on matrix flow and inclusion rotation under viscous simple shear flow. Rigid inclusions of different shape (circle, square, ellipse, lozenge, rectangle and skewed rectangles) and aspect ratio (R) were used. The calculated matrix flow pattern is neither bow tie nor eye-shaped. It is a new flow pattern that we call cat eyes-shaped, which is characterized by: (i) straight streamlines that slightly bend inwards at the inclusion's crests; (ii) elongate eye-shaped streamlines on each side of the inclusion; (iii) stagnation points in the centre of the eyes; (iv) absence of closed streamlines surrounding the inclusion; (v) changes in flow configuration with inclusion orientation; the lines of flow reversal bend and tilt, closed streamline circuits may disappear, and streamlines may bend outwards at the inclusion's crests.Concerning inclusion rotation, the numerical results show that: (i) a low-viscosity layer (LVL) makes inclusions with R = 1 rotate synthetically, but the rotation rate depends upon shape (circle or square) and orientation. Therefore, shape matters in the slipping mode. (ii) All studied shapes with R > 1 rotate antithetically when starting with the greatest principal axis (e₁) parallel to the shear direction ( = 0°); (iii) rotation is limited because there is a stable equilibrium orientation (_se) for all studied shapes with R > 1. (iii) There is also an unstable equilibrium orientation (_ue), and both _se and _ue depend upon inclusion's R and shape.The present numerical results closely agree with previous results of analogue experiments with a permanent low viscosity interface. Only minor deviations related with small shape differences were detected.  相似文献   

Urban transformation of river landscapes in a global context   总被引：8，自引：1，他引：8  

Anne Chin   《Geomorphology》2006,79(3-4):460

Over the past 50 years considerable progress has been made in understanding the impacts of urban development on river processes and forms. Such advances have occurred as urban population growth has accelerated around the world. Using a compilation of research results from more than 100 studies conducted in a range of areas (58 addressing morphological change), this paper describes how urbanization has transformed river landscapes across Earth’s surface, emphasizing the distribution of impacts in a global comparative context. Urban development induces an initial phase of sediment mobilization, characterized by increased sediment production (on the order of 2–10 times) and deposition within channels, followed by eventual decline that couples with erosion from increased runoff to enlarge channels. Data from humid and temperate environments around the world indicate that channels generally enlarge to 2–3 times and as much as 15 times the original size. Although research has emphasized temperate environments, recent studies of tropical areas indicate a tendency for channel reduction resulting from strong sediment erosion and deposition responses because of intense precipitation and highly weathered soils. Embryonic research in arid environments further suggests variable river responses to urbanization that are characterized by rapid morphological change over short distances. Regardless of location, the persistence of the sediment production phase varies from months to several years, whereas several decades are likely needed for enlarging channels to stabilize and potentially reach a new equilibrium. Urbanizing streams pose particular challenges for management given an inherent changing nature. Successful management requires a clear understanding of the temporal and spatial variations in adjustment processes.  相似文献   

基于三维有限元分析的土钉支护结构优化设计研究     

张远芳  高盟 《水文地质工程地质》2006,33(5):106-109

通过建立三维有限元模型，对土钉支护的变形和受力性能进行分析，得出土钉力的合理分布。在此基础上，考虑土钉支护的水平位移，采用遗传算法＋复合形法，对土钉支护的结构优化设计进行研究，建立了土钉支护结构的优化设计数学模型，并编制了相应的计算程序。通过算例分析，并与基于极限平衡分析的优化结果相比较，得出合理的土钉支护结构设计的参考结论。  相似文献