Spilling into confinement: submarine slope valleys as pollutant and carbon sinks

Organic carbon and pollutant concentrations in the modern ocean are poorly constrained. In particular, ocean floor channels on slopes, which are the main conduits for particulate transfer from continents to oceans, are not considered as important sinks for particulates. In part, this is because modern erosionally-confined systems form complicated geomorphologies, but their erosional nature and present-day inactivity means little is known about their evolution. Whilst channels are dominated by erosion for much of their lifespan, their corresponding overbank deposits have not been investigated. However, the sedimentary processes of these features are poorly constrained because they are rarely identified in the rock record, or intersected by wells in modern systems. The dynamic morphology and complex fluid dynamics of the flows within these channels has never been captured experimentally or numerically. Novel physical experiments will comprise a larger outer surface to represent the slope valley confinement, and smaller inset sinuous channel forms, both leveed and terraced, will mimic the thalweg channel. In parallel, the 3D CFD modelling component (ANSYS CFX) will aim to replicate the erosion and deposition from different levels of density stratified flows from the physical experiments where the input parameters and boundary conditions are well constrained.