Supplementary material for: Mantle conveyor beneath the Tethyan collisional belt

The surface mechanical boundary conditions for most of our models are shear stress free (free slip), such that plate velocities are driven self-consistently by density contrasts within the mantle (Ricard and Vigny, 1989). The lithosphere in our models is defined rheologically as a relatively stiff layer from the surface to 100 km depth that is “broken” by weak zones of reduced viscosity, as in previous modeling (e.g. King and Hager, 1990; King et al., 1992; Zhong et al., 2000; Yoshida et al., 2001; Faccenna and Becker, 2010). The location of the weak zones used for most models (Fig. 2A) was assigned for the major plate boundaries following the NUVEL-1 geometry, and, for the case of Asia, located at the boundary of the actively deforming region (e.g. England and Molnar, 2005). All velocities are plotted in an Eurasia fixed reference frame (from a best-fit of the velocities within that plate, which typically show large intraplate deformation), and the core-mantle boundary is set to free-slip.