REPEATING PATTERNS IN MINERAL ENERGETICS

Several recurring themes emerge from years of study of the thermodynamics of mineralogical and ceramic systems. These common features are as follows: (1) acid-base interactions determine the energetics of formation of crystals, glasses, and melts; (2) entropy terms arising from configurational, vibrational, and electronic factors are important at high temperature and pressure; (3) in many cases, short-range interactions and local order dominate energetics; and (4) structural states at high temperature and pressure are often not quenchable to ambient conditions, making in-situ study essential for a reliable picture of mineral properties under conditions within the crust and mantle. Examples illustrating each of these themes are presented. The relations among microscopic interatomic interactions and macroscopic physical properties are crucial to understanding processes on a geologic scale.