Glacial isostasy: Models for the response of the Earth to varying ice loadsRalf GREVE AbstractTwo types of models for glacial isostasy, the response of the body of the Earth to temporally varying ice loads, are reviewed. The first class, referred to as "simple models", comprises a lithosphere and an asthenosphere layer, the dynamics of which are parameterized in a simple fashion. The lithosphere is treated either as locally responding or as a thin elastic plate, the asthenosphere either as relaxing or as a viscous fluid in a thin layer. The combinations of these approaches generate four different variants of simple models. A physically more adequate description is achieved by modelling the Earth as a self-gravitating, viscoelastic, n-layer (SGVE) body, which reflects the structure of the Earth more realistically and allows for a three-dimensional computation of the fields of displacement, stress, density and gravity. The isostasy models are compared by coupled simulations with a dynamic/thermodynamic model for the Antarctic ice sheet. It turns out that, of the simple models, the lithosphere uplift pattern of the elastic lithosphere/relaxing asthenosphere combination agrees best with the SGVE result. Continuum Mechanics and Applications in Geophysics and the Environment (eds. B. Straughan, R. Greve, H. Ehrentraut and Y. Wang), pp. 307-325 (2001). Springer, Berlin, Germany etc. |
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