Publications

The Seram Trough is situated in a complex region where convergence between the Eurasian, Indo-Australian and Pacific plates has been active since at least the Oligocene. It has been interpreted as a subduction trench, a zone of intra-plate deformation, and of strike-slip faulting. Many studies in the Banda Arc, especially the Seram Trough, have discussed its geological evolution, but its nature remains enigmatic. High resolution multibeam bathymetry and seismic data offer an opportunity to assess different hypotheses related to the character and significance of the Seram Trough. North of Seram, at the western end of the trough, the Buru Basin is dominated by E-W trending extensional faults. Further east, offshore of north Seram, the trough trends E-W, then bends through 90° and structures change from E-W to N-S trending thrust faults and folds associated with strike-slip faults. The Seram Trough lacks most features of a subduction trench and is interpreted as a deformation front of a fold thrust belt resulting from oblique young convergence between the Outer Banda Arc and Bird’s Head of New Guinea. The Buru Basin is structurally distinct from the Seram Trough. Contraction in the Late Miocene formed the Misool-Onin-Kumawa Ridge (MOKR), followed by formation of an Early Pliocene unconformity. The development of the Seram fold thrust belt began in the Late Pliocene. The fold thrust belt zone is narrower in the west and widens to the southeast. Thrusting in Seram increased crustal loading and caused subsidence and tilting to the north and east of the trough. Thrusting at the trough started in the Late Pleistocene. Younger deformation includes strike-slip faulting. To the north of west Seram, left-lateral strike-slip faults indicate that the trough is beginning to develop into the Buru Basin.