Publications

The modern slope offshore Brunei provides an outstanding opportunity to document the relationships between water bottom bathymetry, depositional gradients, and sediment dispersal patterns. The study covered an area of 10,000 km2 extending from depths of 950 m to 2800 m reflecting a middle slope to basin floor setting. In contrast to the elliptical salt withdrawal intraslope basins of the Gulf of Mexico, the bathymetric profile offshore Brunei is best described as a “stepped slope characterized by elongate, structurally controlled mini-basins. Progressive basinward thrusting, driven by regional tectonism and up-dip sediment loading of the Baram delta, has divided the area into alternating, shelf edge parallel, thrust-cored structures and elongate mini-basins (Figure 1). The mini-basins are 2-10 km in width and 20-60 km in length. Sediment dispersal pathways are quite tortuous across the irregular bathymetric relief. An additional structurally induced complexity is the fact that local flow vectors are commonly oriented in shelf edge parallel directions within individual mini-basins. The yellow vs. blue flow lines (Figure 2) highlight the alternation in axial flow paths within individual mini-basins (NE-SW vs. SW-NE). A single flow path can extend for >60 km and cross a variety of depositional elements along its length. These elements include: 1) submarine canyons, 2) sediment dispersal fairways and slope channel systems which include straight erosional channels and sinuous leveed channels, 3) distributary channel/lobe complexes, and 4) local cohesive slump complexes up to large scale mass transport complexes (McGilvery and Cook, 2003, McGilvery and Cook, this volume).