Oceanic flood sedimentation: a new perspective

A new type of flood, an oceanic flood, is recognized. In contrast to seasonal floods that characterize moderate to large rivers, oceanic floods occur over short time periods on small rivers. A key aspect of oceanic floods is that the river–ocean system responds to the same storm system. Therefore, sediment is delivered to the ocean under a narrow range of oceanographic conditions. Because large quantities of fine-grained sediment are rapidly introduced to the sea during oceanic floods, the sediment dispersal capacity of the coastal ocean is often overwhelmed. New phenomena (e.g., fluid-mud flows) may therefore arise. Oceanic flood sedimentation is likely to be globally significant, especially with respect to the supply of fine-grained material to slope environments. Long-term changes in precipitation intensity suggest that oceanic floods will be even more common in the future. Studies of oceanic flood sedimentation require novel sampling strategies, such as event-driven coring.