About: Slab detachment

In plate tectonics, slab detachment or slab break-off may occur during continent-continent or arc-continent collisions. When the continental margin of the subducting plate reaches the oceanic trench of the subduction zone, the more buoyant continental crust will in normal circumstances experience only a limited amount of subduction into the asthenosphere. The slab pull forces will, however, still be present and this normally leads to the breaking off or detachment of the descending slab from the rest of the plate. The isostatic response to the detachment of the downgoing slab is rapid uplift. Slab detachment is also followed by the upwelling of relatively hot asthenosphere to fill the gap created, leading in many cases to magmatism.