• Deposition – process by which wind, water, ice, and gravity leave eroded sediments in new locations • What types of landforms are caused by deposition? • • • • • Deltas Sandbars Islands Sand Dunes Alluvial Fans Deltas • Deltas occur at the end of a river. • The end of a river is usually a large body of water such as a lake, bay, ocean or gulf. Mississippi River Delta Notice the sediment that is flowing down the river and out into the Gulf of Mexico. This sediment is building the delta. Nile River Delta • Typical delta shape - like a triangle. Gulf Coast Plains and Marshes • Wave action, a cause of weathering, erosion and deposition, is constant along the Texas Coastline. • Sediments are weathered and eroded along beaches and carried out into the ocean to form sand bars and islands. Mustang Island • Mustang Island in Port Aransas, Texas. • How was this formed? Sandbar • Sandbars happen on the sides of the river. • As the river slows down, it allows the heavier sediment to drop out of the water and deposits it in the sandbar. Sandbars • Sandbars can be large and long lasting. • This one was named in 1898 Whitaker’s Point and has stayed in place since then. Sand Dunes • Wind erosion deposits the sand. Waves and Deposition • http://app.discoveryeducation.com/player/vie w/assetGuid/B0A92767-4528-41D4-BD06C8076220E272 Alluvial Fan • This landform is shaped like a delta. • It happens when rainwater from the mountains runs through a canyon. • The deposits are left in the valley rather than the ocean. Alluvial Fan • This alluvial fan is in Death Valley, California. • Notice the road that has been built around it. Death Valley, Ca. • Death Valley, Ca. is a valley with no outlet. • The water that comes into the valley can not get out. • It just evaporates leaving white deposits of minerals. Death Valley • The white deposits are sodium borate. • This chemical poisons the small ponds that are formed and so no animals or plants can live there. • Which of the following landforms is not formed by deposition? • alluvial fan • delta • river valley • Which of the following landforms is found at the end of a river where it enters a large body of water? • alluvial fan • delta • sandbar • How can you tell the difference between a delta and an alluvial fan? • An alluvial fan is at the bottom of a mountain • A delta is at the bottom of a mountain • Deltas only occur in deserts • Why do sandbars for in the curve of a river? • The river speed up and drops the sand • The river loses speed and drops the sand • There is a pile of rocks that catches the sand • Which of these processes is in the correct order? • weathering, deposition, erosion • deposition, weathering, erosion • weathering, erosion, deposition • Explain what would happen over time to a rock cliff on the ocean’s edge. Describe the whole process and what the result might be.