Brian Taylor, Andrew Goodliffe, R. N. Hey and F. Martinez (SOEST, University of Hawaii, 2525 Correa Road, Honolulu, HI, 96822; andrew@mano.soest.hawaii.edu)
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 m.y. 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 preexisting 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.