Interactions between a transform fault and arc volcanism in the Bismarck Sea, Papua New Guinea

Abstract

We present a new interpretation of the geological evolution of the western branch of the Bismarck Sea Seismic Lineation (BSSL) region, offshore the northwestern coast of Papua New Guinea, from mapping and interpretation of bathymetry and backscatter data acquired aboard R/V Kilo Moana in 2004. At present, the Schouten Islands parallel the Papua New Guinea coast, but this distribution results from the left-lateral displacement of some of these volcanic islands by the Bismarck Sea Seismic Lineation. The trend of the islands and seamounts was initially aligned N-S and then displaced by the BSSL. Wei Island lies on a large submarine edifice that may have formed as part of a leaky transform. Subsequent to forming, Wei Island was bisected, and its pieces were displaced 45 km. Using this distance together with the strikeslip rate for the Bismarck Sea Seismic Lineation (predicted from the North Bismarck Plate-South Bismarck Plate pole), the division occurred approximately 385,000 years ago.