Q:

How are sea stacks formed?

A:

Quick Answer

Sea stacks form as a result of the constant crashing of oceanic waves against a cliff. Erosion creates sea caves out of the cliff, and arches develop over time. As the rock is worn down further, the arches become sea stacks.

Know More

Full Answer

Sea caves form when the strong energy of the waves creates cracks in the rock surface. Over time, the cracks become larger, eventually forming blowholes. The waves continue to erode the blowholes, and they become sea caves. If the cliff juts out into the ocean, the waves can break down both sides of the rock, turning sea caves into arches. If one half of the arch is softer than the other, the softer side breaks down faster, leaving one side to become a sea stack.

A sea stack located off the coast of Oregon called Jump-Off Joe was made of sandstone, eroding over the course of the 20th century. Other sea stacks in Bandon Beach, Ore. are composed of sandstone or chert, rocks that are relatively hard when measured on the Mohs scale. Waves erode rocks through corrosion and hydraulic action, but the waves can only quickly break down rock that is soft. The inner part of the headland or cliff that is harder takes a longer time to break down into sea caves or arches. The process continues until the waves push the coastal landscape further inland.

Learn more about Landforms

Related Questions

  • Q:

    How are cliffs formed?

    A:

    Cliffs form through tectonic activity, water movement, weathering, erosion and glacier activity. Earthquakes and landslides also form cliffs. Cliffs tend to form on coasts, in mountainous areas, along rivers or as the walls of canyons.

    Full Answer >
    Filed Under:
  • Q:

    How are floodplains formed?

    A:

    The Center for Earth and Environmental Science describes that floodplains are formed as rivers erode their own banks. Floodplains are the flat lands that lie adjacent to a river; they encompass the area that floods when the river's water level rises. As the river flows, it washes material downstream. When a flood occurs, this material is resuspended in the water and added to the floodplain.

    Full Answer >
    Filed Under:
  • Q:

    How are islands formed?

    A:

    Islands form in several ways. The most common events that lead to island formation are volcanic activity and continental drift. Islands also form due to erosion, buildup of sediment and coral that grows enough to penetrate the surface of the water.

    Full Answer >
    Filed Under:
  • Q:

    How is a strait formed?

    A:

    A strait is either formed by tectonic shifts or land that has subsided or been eroded. If a strait is created by people rather than geological forces, it is generally referred to as a canal.

    Full Answer >
    Filed Under:

Explore