What causes rocks near a river to become smooth and rounded
Please see your later post, which I saw first.
Sra
P.S. If you are not Ravin, look at his answer.
Sra
The process of rocks near a river becoming smooth and rounded is called "riverine erosion." It occurs due to the combined effects of various environmental factors at work. Here's an explanation of the process:
1. Water Flow: The force of moving water is the primary factor responsible for wearing down and shaping rocks. As a river flows, it carries sediments, sand, and smaller rocks with it. When these particles come into contact with larger rocks, they get dragged along and act like sandpaper, abrading the surface of the rocks.
2. Hydraulic Action: The force of water hitting rocks causes small fragments to break off. The water gets trapped in cracks and crevices, exerting pressure that gradually weakens the rock and contributes to its erosion.
3. Abrasion: As mentioned earlier, the sediment particles carried by the river act like natural abrasives, continuously rubbing against the rocks. This grinding action over time results in the rocks becoming smoother and more rounded.
4. Tumbling: When rocks are in fast-flowing water, they can move and collide with each other. These impacts cause bits of rock to chip off, resulting in rounding and smoothing over time.
5. Chemical Weathering: River water also contains dissolved chemicals that can interact with the minerals in rocks. Over time, these chemical reactions can weaken the rock, making it more susceptible to physical erosion.
It is important to note that the degree of smoothness and rounding also varies depending on the type and hardness of the rock, as well as the speed and volume of the river's flow.