Dynamical effects of subducting ridges: insights from 3-D laboratory models

摘要: SUMMARY We model using analogue experiments the subduction of buoyant ridges and plateaus to study their effect on slab dynamics. Experiments show that simple local (1-D) isostatic considerations are not appropriate predict behaviour during a ridge perpendicular trench, because rigidity plate forces subduct with dense oceanic lithosphere. Oceanic parallel trench have stronger process they simultaneously affect longer segment. Large segments sink more slowly into asthenosphere, result in diminution velocity plate. We observe steeping below those anomalies, resulting smaller radius curvature augments energy dissipated folding further diminishes subduction. When 3-D geometry plateau is modelled, dip above decreases, as larger ‘normal’ both sides plateau. Such perturbation maintains long time after has been entirely incorporated zone. compare present-day zone South America. suggest modest such Juan Fernandez enough modify geometry. Already subducted anomalies within plate, contrast, may be responsible for some aspects Nazca at depth.