Recent GPS observations in central and southeast Asia indicate that the entire eastern margin of Asia is moving eastward, independent of Tibet motion. This result argues that the eastward motion of south China is not a result of the India-Eurasia collision. Therefore, we investigate an alternative source that may be responsible for driving the observed eastward motion. Specifically, we investigate stresses associated with (1) lithospheric density variations and (2) basal tractions resulting from large-scale density buoyancies, with interest in the effects resulting from the eastern subduction systems. Using a self-consistent set of GPS observations and Quaternary fault slip data we first determine a continuous model strain rate and velocity field for central and southeast Asia. Deviatoric stresses associated with lithospheric density variations are determined from the CRUST2.0 data set. These calculations are performed globally to avoid boundary effects but only considered within the region of interest. We then solve for stress field boundary conditions in this region, which represent the effects of large- scale mantle flow associated with deeper density buoyancies. Separately, we use CitcomS combined with published tomographic models and history of slab subduction to determine mantle flow and associated stress field at the base of the lithosphere. By detailed comparisons between the stress field boundary conditions and the deviatoric stress fields resulting from mantle convection, we isolate the relationship between the eastward motion of central Asia and surrounding subduction systems.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 8104 Continental margins: convergent;
- 8120 Dynamics of lithosphere and mantle: general (1213);
- 8164 Stresses: crust and lithosphere