New Guinea is a mountainous island in a tectonically active setting with regions experiencing rapid uplift rates as shown by the celebrated emergent coral reef terraces of the Huon Peninsula. In the northern Bird's Head Peninsula of northwestern New Guinea, rapid uplift has been a feature of the tectonic history over the past 2.7 Ma with the development of the mountainous and highly dissected Kemum High (up to 2200 m) associated with the formation of the Central Bird's Head Monocline, implying a long-term uplift rate approaching 0.8 m/ka. In this work, Late Quaternary uplift rates of up to 1.28 m/ka were determined for emergent coral reefs in the Manokwari region (northeast of the much larger Kemum High). The rapid uplift rates are based on 230Th-U ages (2.7 ± 0.3 to 246.3 ± 8.0 ka with most ages in the range 69–128 ka) on corals and coralline algae, sampled from calcarenites at elevations of 2.45–77.5 m above present sea level. The rapid uplift indicates neotectonic ac
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