Synchronous reorientation of the Woodlark Basin spreading center

A sidescan and multibeam bathymetry survey of the Woodlark Basin reveals that its 500 km long spreading center reoriented synchronously, without propagation, about 80 ka. There is no evidence of the V-shaped pseudofault geometry typical of spreading center propagation, nor of the progressive fanning of seafloor fabric characteristic of spreading center rotation. The reorientation is recognized by a sharp contact between two seafloor fabric trends, and ruptured off-axis lithosphere formed up to 0.7 Myr previously. The length of the reoriented spreading segments and the tendency to fault pre-reorientation seafloor fabric are controlled by the strength of the lithosphere, the angle of the reorientation, and the length of pre-existing spreading and transform segments. We document the process of synchronous reorientation in the Woodlark Basin and propose that it may occur in other ocean basins.