Viskoelasticita Maxwellova typu v malých i velkých deformacích plášťů terrestrických planet

Patočka, Vojtěch

Title: Maxwell-type viscoelasticity in small and large deformations of planetary mantles Author: Mgr. RNDr. Vojtěch Patočka Department: Department of Geophysics Supervisor: prof. RNDr. Ondřej Čadek, CSc., Department of Geophysics Abstract: A present limitation of global-scale simulations of planetary interi- ors is that they assume a purely viscous or viscoplastic flow law for solid rock, i.e. elasticity is ignored. This is not a good assumption in the cold and strong outermost mantle layer known as the lithosphere, which seems to maintain its elastic properties even on time scales corresponding to the geological processes of subduction or sedimentation. Here we overcome such simplification and present a numerical tool for modelling visco-elasto-plastic mantle convection. The most promising new feature of the resulting models is related to the ability of vis- coelastic materials to remember deformation experienced in the past. Thus, the growing viscoelastic lithosphere of a cooling planet, when subject to internal or surface loading, can store information about its thickness at the time of loading. This phenomena is consistent with datasets of the effective elastic thicknesses determined in flexure studies and we label it here as the "stress memory effect". Attention is also paid to the theoretical foundations...

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