Agents of Erosion & Deposition

1. Agents of Erosion & Deposition By: Myesha & KaShawn

2. Shoreline Erosion & Deposition • Shoreline- where land & a body of water meet • Beach- an area of a shoreline made up of material deposited by waves • Longshore current- movement of water near & parallel to the shoreline

3. -The wind from storms usually produces the large waves that cause shoreline erosion. -Waves break when they enter shallow water, becoming surf.-Beaches are made of any material deposited by waves.-Sandbars & spits are depositional features caused by long shore currents.-Sea cliffs, sea caves, sea arches, & seastacks are coastal formations caused by erosion.

4. This is an example of shoreline erosion.

5. Wind is an important agent for erosion & deposition in deserts & along coastlines. • Saltation is the process of the wind bouncing sand grains downwind along the ground. • Deflation is the removal of materials by wind. If deflation removes all fine rock materials, a barren surface called desert pavement is formed. • Abrasion is the grinding & wearing down of rock by other rock of sand particles.

7. Wind Erosion & Deposition • Saltation- movement of sand size particles by a skipping & bouncing action in the direction the wind is blowing • Deflation- lifting & removal of fine sediments by wind • Abrasion- grinding & wearing down of rock surfaces by other rock or sand particles • Dunes- mounds of wind deposited sand • Loess-thick deposits of windblown fine grain sediments

8. Before After

9. Erosion & Deposition by Ice • Icebergs- large pieces of ice that break off an ice shelf & drift into the ocean • Crevasse- a large crack that forms where the glacier picks up speed or flows over a high point • Glacial drift- the general term used to described all material carried & deposited by glaciers • Stratified drift-rock material that has been sorted & deposited in layers by water flowing from the melted ice • Till- the second type of a glacier drift

10. Because glaciers are very heavy and have the ability to move cross the earth’s surface, they are capable of eroding moving, and depositing large amounts of rock materials. One common type of alpine glacier is a valley glacier which form from valleys originally created by stream erosion. These glaciers flow slowly downhill, widening and straightening the valleys into broad U-shapes as they travel. Continental glaciers continue to get larger, spreading across entire continents. Continental ice sheet is the largest type of glacier. The thickness of the ice and the steepness of the slope determines how fast a glacier will move. Glaciers move by 2 different methods: 1) they move when the weight of the ice causes the ice at the bottom to melt.(the water from the melted ice allows the glacier to move forward, like a partially melted ice cube moving across the kitchen counter.2)solid ice crystals within the glacier slip over each other, causing a slow forward motion.(like placing a deck of cards on a table and tilting it.

11. There are main types of glacial deposits stratifiedtillsome of the landforms deposited by glaciers include outwash plains and moraines.Outwash plain- streams carry an abundance of sorted material which is deposited in front of the glacier in an broad area.Moraines- are the most common till deposits which generally form ridges along the edges of glaciers.

12. Gravity’s Effect on Erosion & Deposited • Mass Movement- the movement of any material, such as rock, soil, or snow, down slope • Rock Fall- when a group of loose rocks falls down a steep slope • Landslide- the sudden & rapid movement • Mudflow-a rapid movement of a large mass of mud • Creep- the extremely slow movement of material down slope

13. Mass movement is controlled by the force of gravity and can occur rapidly or slowly.The angel of repose is the steepest slope at which loose material will remain at rest .(if the slope on which a material rest is less than the angle of response, the material will stay in place. If the slope is greater than the angle of repose, the material will move down slope)Rapid mass movement – the most destructive mass movements occur suddenly and rapidlyRock falls, landslides, and mudflows are all types of rapid mass movementsSlow mass movement- happen little at a timecreep is an example