Numerical modeling of flow patterns around subducting slabs in a viscoelastic medium and its implications in the lithospheric stress analysis |
| |
| Authors: | Nishant Kumar Shamik Sarkar Nibir Mandal |
| |
| Institution: | 1.Indian Institute of Science Education and Research-Kolkata,Kolkata,India |
| |
| Abstract: | This paper presents results obtained from numerical model experiments to show different patterns of mantle flow produced by
lithospheric movement in subduction zones. Using finite element models, based on Maxwell rheology (relaxation time ∼ 1011S), we performed three types of experiments: Type 1, Type 2 and Type 3. In Type 1 experiments, the lithospheric slab subducts into the mantle by translational movement, maintaining a constant
subduction angle. The experimental results show that the flow perturbations occur in the form of vortices in the mantle wedge,
irrespective of subduction rate and angle. The mantle wedge vortex is coupled with another vortex below the subducting plate,
which tends to be more conspicuous with decreasing subduction rate. Type 2 experiments take into account a flexural deformation
of the plate, and reveal its effect on the flow patterns. The flexural motion induces a flow in the form of spiral pattern
at the slab edge. Density-controlled lithospheric flexural motion produces a secondary flow convergence zone beneath the overriding
plate. In many convergent zones the subducting lithospheric plate undergoes detachment, and moves down into the mantle freely.
Type 3 experiments demonstrate flow perturbations resulting from such slab detachments. Using three-dimensional models we
analyze lithospheric stresses in convergent zone, and map the belts of horizontal compression and tension as a function of
subduction angle. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
