Summary of Basic Thermodynamic Concepts: A Refresher

Abstract

One goal of geological research is to understand the physical and chemical processes responsible for the origin and evolution of the earth. In terms of time and space, most such processes are not accessible to direct observation, but they can be reconstructed by deciphering the physicochemical frameworks of formation of rocks and mineral deposits which formed in response to them. Supposing the observed mineral assemblage preserved in a rock records the state of chemical equilibrium, thermodynamics can help translate the compositional data on the coexisting minerals to temperature and pressure of their equilibration. What thermodynamics cannot do is to tell us how long a quenched mineral assemblage is likely to survive once it is outside its field of stability, or what the mechanism of a certain mineral reaction will be. Such questions — geologically of equal importance — can be answered by kinetics, a subject not treated in this book.