Figure 14. Models previously proposed to explain the geodynamic evolution of the Alboran region. These models may be categorized in terms of roll-back or detachment of lithosphere and whether or not crust is involved in recycling of the lithosphere into the mantle. (a) Retreat from east to west of an east dipping subducting slab during the Early Miocene . (b) Break off of a NW dipping slab at the Oligocene-Miocene boundary perhaps subducted during earlier (mainly Cretaceous) eastward movement of Iberia relative to Eurasia . (c) Delamination (in the sense of) of lithosphere thickened during Paleogene convergence initiated during Early Miocene but still active today . (d) Convective removal during the Early Miocene of mantle lithosphere thickened during Paleogene convergence .