Wave-cut platforms form where the sea erodes into the land. Because surf erosion cannot dig down below the base of the surf zone, a fairly level surface results, the wave-cut platform, made up of the wave-cut bench at the cliff base and the abrasion platform farther offshore. Remnant rock knobs are called chimneys.
Fluctuating sea level creates wave-cut platforms at different elevations, either above or below the present sea level. The land, too, may change its elevation.
This gallery shows two kinds of "fossil" wave-cut platforms. On tectonically active coasts, land movements due to plate tectonics may raise the wave-cut platform above the sea. This is very slow compared to sea-level changes. On glacial coasts, the land is depressed by thick ice, ready to rise again when the ice melts. During this period of isostatic rebound, the sea may cut a platform that emerges as the land rises. Isostatic rebound is comparable in speed to sea-level changes. This gallery shows both tectonic and isostatic platform types.
Fossil platforms are commonly called wave-cut terraces or marine terraces. But "terrace" refers to a platform that is built up by deposition, not carved by erosion.
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