by 1 Cylivers
Rock-cut basins are formed by the action of fast running water currents that cause small boulders to move in a circular motion or Vortex.
The friction created by these kolks propelling small boulders in a circular motion erodes the natural rock substrate to create concavities called rock-cut basins, that increase in depth and circumference over the years. One or more rounded stones may be found within them, often of varying sizes as these stones also wear away with the physical abrasion effect.
The conditions on the river bed must be just right, so that the 'abrasion stones' remain in approximately one area as they circle, allowing the processes which create the rock-cut basins to occur.
During times of heavy flood, river currents provide considerable energy to stones lying on the bottom, as can be witnessed beside many rivers where audible sounds are made by boulders as they are tumbled downstream over the bedrock or as they clash against other boulders. The term Bed load is used to describe the material carried by a river by being bounced or rolled along its bed.
