Ostwald processes and mineral paragenesis in sediments

Abstract

The sequential formation in time (paragenesis) of minerals in sediments frequently results in the formation of phases not predicted by equilibrium thermodynamics. For several important groups of minerals paragenesis follows the qualitative Ostwald step rule for sequential reactions, and in some cases (silica) the process of Ostwald ripening is intimately associated with such diagenetic sequences. Kinetic theories of grain coarsening provide considerable insight into the growth of minerals during diagenesis. Because the time during diagenesis often translates into sediment depth, these relations provide a way to test the importance of Ostwald ripening as a major process of diagenesis. -from Authors