Define abrasion in the context of coastal processes.

In the context of coastal processes, abrasion refers to the grinding away of rock surfaces by particles that are carried by waves. This process involves the physical wearing down of rock formations along the coast as a result of the action of moving water, which transports loose sediments and other materials that collide with and scrape against the rock surfaces. Over time, this action can significantly shape coastal landscapes, leading to the formation of features such as cliffs and shore platforms.

This process is essential in understanding coastal erosion and sediment transport. Compared to the other options, which describe different geological processes, abrasion specifically highlights the mechanistic interaction between waves and coastal materials, making it a crucial element in coastal geomorphology. For instance, dissolution of rocks by seawater involves chemical processes rather than physical grinding, while the gravitational pull of tides deals more with water movements rather than direct contact actions like abrasion. Similarly, the buildup of sediment on beaches relates to deposition rather than the wear and tear caused by moving particles, which is at the core of abrasion.