Corrosion occurs when water in the form of waves dissolves rock minerals. Minerals are instantly swept away by the solution wave. They are also prone to erosion caused by precipitation and sea spray. Most effectively: constructive waves, since the intensity of contact is irrelevant, and the spilled wave lengthens the time it takes for the chemical reaction to occur.
Convergent boundaries work similarly to constructive waves. Here the risk is that at some point the two sides will meet and merge, causing a barrier against further movement. Barriers can be overtopped by more intense waves or removed entirely. A common example is a riverbank eroded away by the action of the stream itself. Re-emerging as grassy meadows shows how effective the flow was in removing the rocky material from around its base.
Divergent boundaries arise where parts of the boundary move away from each other. There are two main types of divergent boundary: those formed by cliffs or rocks, and those formed by soft sedimentary deposits such as silt or clay. In both cases, the energy of the water has been taken advantage of to break down the hard surface, creating new land. The main difference between the two types of divergence is how far they go before meeting again. With cliffs this is usually only a few hundred meters, but with sediments the distance could be much greater. For example, if the cliff is made of shale then it might only be a meter deep but extend for many kilometers along the coast.
The right example of natural erosion is waves washing over rocks on the beach because waves from any body of water are naturally formed by the impact of wind and gravity and can wipe the surface materials existing over the rocks on the beach.
Waves are the most common form of natural erosion, and they can wear away rock layers on a coastline. The shape of the coast itself can also play a role in how fast it erodes. Where there are steep cliffs or deep valleys, the rock falls into these features and is never seen again. Where the land is more level, wave action wears it away until nothing remains but the sand below.
Waves come in different shapes and sizes. Flat beaches are usually made of fine white sand that gets washed away by waves and currents. Rocky coasts are made of stone and are worn away by pounding surf. Beaches with mixed material compositions include those with cobblestones, which come from eroded rocks, and shells, which come from the ocean floor. All types of shoreline can be affected by erosion caused by humans. For example, where gravel pits remove top soil and rock from areas near roads, less of this material is available to hold back water and create gully erosion.
Erosion is the direct or indirect physical removal of earth's surface materials.
Erosion may be classified into four categories. The sheer strength of the waves as they crash against the cliff is referred to as hydraulic action. Air becomes trapped in the crevices of the rock, causing it to break apart. Abrasion occurs when pebbles grind along a rock platform, similar to sandpaper. Chemical erosion takes place when acid in rain or snow dissolves the surface layer of rocks, forming holes or pits. Physical erosion removes material from the face of a cliff by means of water, wind, ice, or gravity. This type of erosion forms gorges and valleys.
Hydraulic action is one of the most important factors in determining how fast a cliff will erode. The energy of the waves is transmitted through the water to the bottom of the cliff, where it can do some damage. The amount of damage done depends on several factors, such as the hardness of the rock, its size, and how far away it is from the shore. Harder rocks resist erosion because the waves have to work harder to wear them down. Larger rocks are able to hold more water than small ones, so they absorb more wave energy. Far-out rocks are not affected as much by hydraulic action because the waves have more room to travel before they reach them.
Rocks near the coast are subjected to both physical and chemical erosion by the waves and ocean currents. As they drift farther from land, these rocks are only subject to physical erosion by water and wind.