On the problem of the mechanism of postglacial rises

Abstract

Summary In this paper one of the possible mechanisms for postglacial uplift is considered. It is based on the known fact of the phase boundary reaction to change in pressure in the medium. Unlike the mathematical model for such mechanisms considered previously in a number of publications, we propose a model that takes into account the supercooling (superheating) on the crystallization (melting) front responsible for a phase transition. The algorithm for a numerical solution to the mathematical model is derived. The solution leads to the following conclusions: 1. Geological data on postglacial uplift are accounted for if the following conditions are observed, (a) There is one phase boundary in the layer subjected to a phase transition. If the layer is bounded by phase boundaries on two sides its thickness should be no less than 200 km. (b) The transition temperature curve and that of the temperature of the medium are close to each other, (c) The latent heat is close to 10 cal g−1. (d) Properties of the mantle rocks are such that the parameter characterizing overheating in the phase transition should satisfy a certain condition. 2. In view of strict limitations set by this work on the phase mechanism, the latter is less probable in a real medium than the mechanism related to viscosity of the mantle.