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Chapter 12:Agents of Erosion & Deposition Section 1: Shoreline Erosion & Deposition < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Energy • When waves crash into rocks over long periods of time, the rocks are broken down into smaller and smaller pieces until they become sand. • Waves usually play a major role in building up and breaking down the shoreline. A shoreline is the boundary between land and a body of water. • As the wind moves across the ocean surface, it produces ripples called waves. The size of a wave depends on how hard the wind is blowing and how long the wind blows. < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Energy, continued The wind that results from summer hurricanes and severe winter storms produces large waves that cause dramatic shoreline erosion. < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Energy, continued • Wave Trains Waves travel in groups called wave trains. When wave trains reach shallow water, the bottom of the wave drags against the sea floor, slowing the wave down. • The upper part of the wave moves more rapidly and grows taller, and begins to curl and break. These breaking waves are known as surf. • The time interval between breaking waves is called the wave period. < Back Next > Preview Main < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Energy, continued • The Pounding Surf Tremendous energy is released when waves break. Crashing waves can break solid rock and throw broken rocks back against the shore. • Breaking waves also wash away fine grains of sand, which are picked up by the waves and wear down and polish coastal rock. • The process continues until rock is broken down in smaller and smaller pieces that eventually become sand. < Back Next > Preview Main < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Erosion • Shaping a Shoreline Wave erosion produces a variety of features along a shoreline. Much of the erosion responsible for coastal landforms takes place during storms. • Sea cliffs are formed when waves erode and undercut rock to produce steep slopes. • Sea caves are formed when waves cut large holes into fractured or weak rock along the base of sea cliffs. < Back Next > Preview Main •Sea arches form when wave action continues to erode a sea cave completely cutting through the rock. •Sea stacks are offshore columns of resistant rock that were once connected to the mainland. < Back Next > Preview Main < Back Next > Preview Main < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Deposits • Beaches are areas of the shoreline made up of material deposited by waves. Some beach material is also deposited by rivers. • Waves carry a variety of materials, including sand, rock fragments, dead coral, and shells. • The colors and textures of beaches vary because the type of material found on a beach depends on its source. < Back Next > Preview Main < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Deposits, continued • Wave Angle and Sand Movement Waves moving at an angle to the shoreline push water along the shore and create longshore currents. • Longshore currents move sand in a zigzag pattern along the beach. < Back Next > Preview Main Chapter 12 Section 1 Shoreline Erosion and Deposition Wave Deposits, continued • Offshore Deposits When waves erode material from the shoreline, longshore currents can transport and deposit the material offshore, which creates landforms in open water. • A sandbar is an underwater or exposed ridge of sand, gravel, or shell material. • A barrier spit is an exposed sandbar connected to the shoreline. < Back Next > Preview Main