An internally consistent thermodynamic database on minerals: Application to the earth's crust and upper mantle.

详细信息   

• 作者：Chatterjee ; Nilanjan.
• 学历：Doctor
• 年：1989
• 毕业院校：City University of New York
• CBH：9009720
• Country：USA
• 语种：English
• FileSize：6406097
• Pages：202

文摘

An internally consistent thermodynamic data base with fifty two common minerals found in the earth's crust and upper mantle in the system Na$\sb2$O-K$\sb2$O-CaO-FeO-MnO-MgO-Al$\sb2$O$\sb3$-TiO$\sb2$-SiO$\sb2$-H$\sb2$O is created by systematization of available calorimetric data and experimental phase equilibrium data. An optimization of the two data sets is carried out through the program MINUIT,in which numerical techniques are used. These techniques include the Monte Carlo search,the simplex and the gradient methods. The data base also includes interaction parameters of forty four different binary solid solutions of common crustal and upper mantle minerals. The method adopted is to work on small sub-systems and then combine them to test for internal consistency. The sub-systems studied extensively are MgO-Al$\sb2$O$\sb3$-SiO$\sb2$,CaO-Al$\sb2$O$\sb3$-SiO$\sb2$,CaO-MgO-Al$\sb2$O$\sb3$-SiO$\sb2$,FeO-MgO-Al$\sb2$O$\sb3$-SiO$\sb2$,MgO-SiO$\sb2$-H$\sb2$O,K$\sb2$O-Al$\sb2$O$\sb3$-SiO$\sb2$-H$\sb2$O,Na$\sb2$O-Al$\sb2$O$\sb3$-SiO$\sb2$-H$\sb2$O and K$\sb2$O-FeO-MgO-Al$\sb2$O$\sb3$-SiO$\sb2$-H$\sb2$O. Recommended thermodynamic properties of most of the minerals studied are within their originally stated calorimetric error limits with the exception of the enthalpies,entropies and heat capacities of gehlenite and Ca-tschermak； the enthalpy and entropy of almandine； the enthalpies of anorthite,spinel,talc and anthophyllite； the entropy and heat capacity of monticellite； the entropy of sanidine and the heat capacity of paragonite. The test of internal consistency is done through computation of phase equilibrium relations in a system of fixed composition by the technique of minimization of total Gibbs free energy of a system. This technique is implemented in Eriksson's program SOLGASMIX (Eriksson,1975). The data base is managed through a program called RETR,which is used to inspect and retrieve thermodynamic properties of pure phases and solid solutions. The data base is used in thermometry and barometry of natural assemblages. It is also used in the calculation of phase equilibria. Two programs,THERMO and REAC,are presented for thermometry and barometry. Thirteen different thermometric reactions are considered in program THERMO. In program REAC,any reaction can be defined from the set of phases being considered. In both programs,the Bertrand-Kohler (Bertrand et al.,1983) model for multicomponent solid solutions is used. The fugacity models of Saxena and Fei (1987a,b),for real gases,are also incorporated in program REAC.