Relief-forming activity of bottom currents in the abyssal zone of the ocean

Abstract

A great geological work is done by stationary or quasi-stationary oceanic bottom currents connected with processes of bottom water masses forming. The currents velocity is about a few centimeters to tens centimeters per sec. The currents (Atlantic Western Boundary Undercurrent, for example) transport huge masses of sediments and deposit them where velocities decrease, giant forms thus being built during millions and tens millions years (like those of Newfoundland or Blake-Bahama «ridges»). In case of great velocities the abyssal bottom currents are able to create linear erosional forms, which could be called «abyssal valleys», some of them being of thousands kilometers long. Some of turbidity currents may contribute to their formation. In general the relief-forming activity of ocean currents, bottom currents in particular, deserves a close consideration as it is a most widespread exogenous geomorphic f actor.