Analogies to oceanic behaviour in the continental breakup of the western Woodlark basin

THE Woodlark basin/D'Entrecasteaux Island region off northeast Papua New Guinea (Fig. 1) offers a rare glimpse of the propagation of active rifting and continental breakup(1) into orogenically thickened (and subsequently extended) lithosphere(2-10). Rifting, continental breakup, and the subsequent formation of oceanic lithosphere by sea-floor spreading often involve rupture controlled by propagation of a rift tip(11-20). We recognize several tectonic elements in the evolving western Woodlark intracontinental system that are close geometric analogues of wholly oceanic propagators, and a kinematic development that can be viewed as an extrapolation of oceanic tectonics. The response to deformational stresses in the final stages of breakup in a thick, relatively hot, and hence weak continental lithosphere appears akin to that of oceanic lithosphere.