What controls turbidity currents flow modes? New insights from direct measurements worldwide

Recent advances in technology are now enabling first high-resolution measurement of active turbidity currents. New data are answering key questions such as what flow modes exist for field-scale turbidity currents? Which are the factors that control flow behaviour? By analysing direct measurements of turbidity currents at different locations worldwide from 65 m to 2300 m water depth we tested whether commonalities in flow mode exist, independent of location, thickness, velocity and flow duration. Our study shows that two main flow modes are possible. Sand-rich systems are typical of canyons with coarse axial sediments (<10% mud) and oceanographic-triggers. Mud-rich systems are those where sediments comprise c.10-40% mud and canyons are directly linked to the rivers activity. We suggest that the grain size is the more significant control factor on setting up flow mode.