The contribution of pressure-induced phase changes to glacial rebound

Abstract

Estimates of the possible magnitude of land surface depression resulting from phase changes produced by continental glaciation are given. Of the possible mineral transformations postulated to explain density increases within the earth, that at the Mohorovicic discontinuity would make the most significant contribution. If this discontinuity is assumed to represent a transformation from eclogite to basalt, ice sheets could from this source alone produce up to 200 meters of land surface depression. However, the most reasonable choice of parameters leads to estimates of between 40 and 120 meters. As the actual land depression produced during the Pleistocene lies between 200 and 800 meters, phase change is probably not the dominant mechanism responsible for glacial rebound. The analysis indicates that because of the adiabatic character of the process glacial loading will not only cause an upward migration of a phase boundary but will transform it into a gradational zone of partial transformation.