ROLE OF ATTACHMENT KINETIC FEEDBACK IN THE OSCILLATORY ZONING OF CRYSTALS GROWN FROM MELTS

The kinetics of attachment of endmember units of a solid solution from melt is shown to allow for the development of autonomous oscillatory zoning through feedback associated with the chemical kinetics of crystal growth. Such oscillatory zoning arises without the intervention of externally imposed periodicities in the state (pressure, temperature, or composition) of the melt from which the crystals grow. A mathematical model of crystal growth from a melt is presented. Topological arguments are used to demonstrate that the model can account for oscillatory zoning. A variety of distinct oscillatory profiles is demonstrated. It is also shown that bifurcation analysis may be used to obtain criteria for the existence of oscillatory zoning. © 1990.