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Modelling of viscoelastic plume-lithosphere interaction using the adaptive multilevel wavelet collocation method

Vasilyev, Oleg V. ; Podladchikov, Yuri Yu ; Yuen, David A.

In: Geophysical Journal International, 2001, vol. 147, no. 3, p. 579-589

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    Title
    • Modelling of viscoelastic plume-lithosphere interaction using the adaptive multilevel wavelet collocation method
    Author
    • Vasilyev, Oleg V.. Department of Mechanical and Aerospace Engineering, University of Missouri-Columbia, Columbia, MO 65211, USA. E-mail:VasilyevO@missouri.edu
    • Podladchikov, Yuri Yu. Geologisches Institut, ETH-Zurich, Sonneggstrasse 5, CH 8092, Zurich, Switzerland. E-mail: yura@erdw.ethz.ch
    • Yuen, David A.. Minnesota Supercomputing Institute and Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55415, USA. E-mail:davey@krissy.msi.umn.edu
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:297871
    Summary
    Modelling of mantle flows with sharp viscosity contrasts in a viscoelastic medium is a challenging computational problem in geodynamics because of its multiple-scale nature in space and time. We have employed a recently developed adaptive multilevel wavelet collocation algorithm to study the dynamics of a small rising diapir interacting with a stiff lithosphere in a Maxwell viscoelastic mantle. In this kinematic model we have prescribed the upward velocity of the diapir and then we need to integrate in time onlythe momentum equation governing the temporal evolution of the pressure, stress andvelocity components, which together constitute a sixth-order system in time. The total number of collocation points did not exceed 104, compared to more than 106 gridpoints using conventional evenly spaced grid methods. The viscosity of the diapir is10−4 times lower than that of the surrounding mantle, while the viscosity of the thinlithosphere, about 5-10 per cent of the entire layer depth, is 104-108 times stiffer than the ambient mantle. Our results demonstrate the efficacy of wavelets to capture thesharp gradients of the stress and pressure fields developed in the diapiric impingement process. The interaction of the viscoelastic lithosphere with therisingviscoelastic diapir results in the localization of stress within the lithosphere. The magnitude of the stress fields can reach around 100-300 MPa. Our simple kinematic model shows clearly that viscoelasticity canpotentially play an important role in the dynamics of thelithosphere, especially concerning the potential severage of the lithosphere by mantle upwellings