Jacques Daniel

Seabeam survey at the southern end of the Manila trench. Transition between subduction and collision processes, offshore Mindoro Island, Philippines

Abstract The morphological and structural study conducted at the southern tip of the Manila trench, reveals that convergence between the South China Sea basin and Luzon is accommodated differently depending on the nature of the subducted slab. When the oceanic crust is subducted, a simple accretionary prism-fore arc basin pattern is developed. Conversely, where the continental margin of this basin is subducted, intraplate deformation is randomly distributed across the major part of the fore arc area which is fragmented into various crustal microblocks. Results of seabeam mapping and detailed geophysical surveying conducted at this subduction-collision transition zone, during the POP2 cruise, with R.V. “Jean Charcot” are presented and discussed here and allow us a new insight into the mechanism of such a subduction-collision transition zone.