The Paleozoic to Early Mesozoic Pacific-facing active margin of East Gondwana has been shown to extend into the Kemum Block of northern Bird Head Peninsula (western New Guinea), and was associated with Mid Paleozoic orogenic deformation and Devonian to Triassic silicic magmatism and foreland basin deposition. In the Mawi Bay area of the eastern Bird Head Peninsula, the (?) Permian Mawi Complex is a multiply-deformed unit with a pre-Late Triassic D1 deformation formed in an Andean back-arc setting associated with active margin tectonism. The D1 deformation is characterized by recumbent, isoclinal to tight, north-northeast facing folds with an axial planar S1 cleavage formed at a low metamorphic grade, and predated the unconformably overlying Upper Triassic - Middle Jurassic Tipuma Formation. South of the Mawi Complex, the Mesozoic-Paleogene succession of the northern Lengguru Fold Belt is affected by north-northwest trending folds, cleavage, and most of the succession dips moderately to
This thesis aims to establish how the late Cenozoic oblique convergence of the Pacific- Caroline and Australian plates has affected the tectonic history of the eastern Bird’s Head Peninsula in northwestern New Guinea. Emphasis is placed on insights provided by >5 magnitude earthquakes since 1976 and the structural geology of Miocene-Pleistocene sediments in the Manokwari area and Permian to Paleogene units of the northern Lengguru Fold Belt around Mawi Bay. The Bird's Head Peninsula is moving west- southwest relative to the Australian Plate based on GPS data, but slower than the west- southwest movement of the Pacific-Caroline Plate. This accounts for plate convergence between the Pacific-Caroline Plate and the Bird's Head Peninsula consistent with earthquakes caused by gently south dipping thrusts in an arc along the northern Bird’s Head coastline and indicating subduction along the Manokwari Trough. Southwards subduction along the New Guinea Trench to the northeast o