Levee (Submarine)

A submarine levee is a raised, wedge-shaped ridge of fine sediment flanking a submarine channel, built by the overspill of turbidity currents. As a flow exceeds the channel depth, its upper, dilute, fine-grained part spills over the banks and drops out, aggrading levees that confine and steer later flows much as river levees do on land. Levees are higher on the outer bank of channel bends and decay downfan as flows lose confinement. They are typically muddy and thinly bedded, in contrast to the sandy channel fill, and they record the flow regime that built a deep-sea fan.