ANALOGIES TO OCEANIC BEHAVIOR IN THE CONTINENTAL BREAKUP OF THE WESTERN WOODLARK BASIN

THE Woodlark basin/D'Entrecasteaux Island region off northeast Papua N ew Guinea (Fig. 1) offers a rare glimpse of the propagation of active rifting and continental breakup(1) into orogenically thickened (and su bsequently extended) lithosphere(2-10). Rifting, continental breakup, and the subsequent formation of oceanic lithosphere by sea-floor sprea ding often involve rupture controlled by propagation of a rift tip(11- 20). We recognize several tectonic elements in the evolving western Wo odlark intracontinental system that are close geometric analogues of w holly oceanic propagators, and a kinematic development that can be vie wed as an extrapolation of oceanic tectonics. The response to deformat ional stresses in the final stages of breakup in a thick, relatively h ot, and hence weak continental lithosphere appears akin to that of oce anic lithosphere.