INTRODUCTION TO THE THEORY OF FORCED EQUILIBRIA - GENERAL-PRINCIPLES,BASIC CONCEPTS, AND DEFINITIONS

Until now, only a small amount of work has been done to verify the con straints of using fundamental regularities of the exact sciences in ge ochemistry and mineralogy. As for the chemical thermodynamics, the mos t important problem is the inadequate presentation of the thermodynami c state of real mineral systems. Our contention is that this state can not be rigorously referred to any conventional type, if examined by th e traditional chemical thermodynamics, and must be analyzed in terms o f forced-equilibrium theory. The forced equilibrium is defined as a sp ecific thermodynamic state resulting from the action of forcing factor s, that is, the conditions or constraints which restrict possible vari ations of principal or internal thermodynamic system parameters. The a dvantage of this approach is that it proceeds from the operative forci ng factor to the actual type of equilibrium of the real system, wherea s the traditional analysis usually postulates the type of equilibrium state without proof of adequacy. The equilibrium conditions for thermo elastic solids with a coherent interphase boundary are a good example of forced equilibrium. The numerical modelling of forced equilibria in some real mineral systems and the comparison of the results with expe rimental and natural data show that the actual thermodynamic states of mineral systems more often represent stable or metastable forced equi libria than kinetically depressed or metastable states in their tradit ional understanding. Copyright (C) 1997 Elsevier Science Ltd.