Figure8

Three dimensional models of accretion of (A) a 250 km and (B) a 500 km radius oceanic plateau (shown with orange markers) into a deformable margin (snapshots of movies from Moresi and Willis (2015)showing only their marker surfaces). The oceanic plate is grey with a yellow strain-marker grid. The continental crust is dark blue with a light grid. Transitional crust is cyan with a grey grid. The indenting plateau is orange. The plate boundary is a purple dotted line. The dark, dashed line indicates the position of the trench at the onset of collision. The colored lines indicate the cross-sectional view of the pre-collision lower-plate lithosphere (green), the plateau (red), and the post-collision lower-plate lithosphere (blue). (C) shows the correspondence between the high-resolution 2D, thermal-mechanical models of Cooper and Miller (2014) and the compositional-mechanical 3D models. (D) is a cross section through the collision of a 125 km radius plateau showing all material elements (Betts et al., 2015) and illustrating a geometry similar to that of the Yakutat subduction and accretion.