Nucleation, Growth, Melting, Dissolution, Chemical Zoning and Morphology

Abstract

Crystal growth involves nucleation and subsequent transport and rearrangement of atoms in disequilibrium to near equilibrium processes. Even after the establishment of large faces, an energy barrier still controls further growth. Many experimental data are available on growth from the melt, on melting and dissolution of feldspars, and on incubation times and nucleation rates in relationship to the structure of liquids. The dependence of oscillatory zoning on local kinetic factors relative to changing physicochemical conditions in a magma is being studied. The growth of new grains and their formation from subgrains during deformation and crystal morphology are briefly treated. Nucleation and growth during exsolution is discussed in Chapter 19. This chapter deals mainly with new developments and experimental data since 1973, due in large measure to the impetus of the Apollo project. Readers should refer to 1, 196–302 for a detailed review of optical data on zoning in feldspars and of crystal morphology and habit, most of which is still valid.