What process creates deltas?

Explanation:

A delta is a process that forms by river deposition into an ocean or marine environment.

Sediments carried by rivers in their old stage are brought near the mouth of an ocean. As the velocity of the river reduces, sediments begins to settle out. Small river tributaries breaks out into the ocean. Delta forms at an interphase between a small and large body of water. The deposited sediments forms distinct shapes as they enter the larger body of water.