Ridge Jumps and Mantle Exhumation in Back-Arc Basins

Back-arc basins in continental settings can develop into oceanic basins, when extension lasts long enough to break up the lithosphere and allow mantle melting that generates new crust. Often, basement of these is not only composed crust, but also exhumed mantle, fragments intrusive magmatic bodies, a complex mid-ocean ridge system characterised by distinct relocations spreading centre. To better understand dynamics lead characteristic structures back-arc we performed 2D numerical models with asymmetric time-dependent boundary conditions simulate episodic trench retreat. We find that, all models, leads rift and/or jumps. In our parameter space, length jump ranges between 1 65 km timing necessary produce varies 0.4 7 Myr. With shortest duration first extensional phase, observe strong asymmetry margins basin, margin further from being outcropping lithospheric section thinned other cases, creates two consecutive leaving fragment basins. Finally, phase form well-developed basin (>35 long), very short intra-oceanic jump. Our are able reproduce many observed today, showing transient nature retreat episodes fast slow cause jumps, exhumation, formation.