Submarine channel flow processes and deposits: A process-product perspective

• Synthesise process-product experiments on submarine channels
• Develop spatial and temporal model of helical flow in submarine channels
• Examine the underlying factors controlling helical flow
• Propose new models for the development of inner bend sedimentary accumulations
• Propose process-orientated models of intra-channel sedimentation

Process-product studies have been central to the development of process sedimentology over the past few decades, with the ability to first measure flows, and then examine the resulting deposits, removing much of the ambiguity associated with previous interpretations. However, perhaps uniquely for large geomorphic systems on Earth, there are no field-scale process-product studies of submarine channels. In fact, there are remarkably few direct measurements even of the flow dynamics as a result of the difficulties of measuring these powerful, infrequent, and often inaccessible flows. Over the past decade, physical experimentation has provided the first process-product studies for model submarine channel systems, enabling us to link flow behaviour and sedimentation patterns. This has been supplemented by numerical simulations, particularly of submarine channel flow dynamics. Here for the first time, we synthesise these observations, in the context of our direct knowledge of submarine channels, to derive an overview of submarine channel flow dynamics, and process-orientated intra-channel architecture models for low and high latitude systems. In addition, we propose new models for the development and evolution of point bars and for inner bend sedimentary accumulations that can comprise point bars overlain by finer-grained oblique accretion deposits. The work reveals a rich range of flow behaviour and associated sedimentation patterns in submarine channels that are far more complex than in fluvial systems.