Agents of Erosion & Deposition

By: Myesha & KaShawn

                                                                  

 

 

Shoreline Erosion & DepositionShoreline- where land & a body of water

meetBeach- an area of a shoreline made up of

material deposited by wavesLongshore current- movement of water near

& parallel to the shoreline

-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, & sea stacks are

coastal formations caused by erosion.

This is an example of shoreline erosion.

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.

Wind Erosion & DepositionSaltation- 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 sandLoess-thick deposits of windblown fine grain

sediments

Before After

Erosion & Deposition by IceIcebergs- large pieces of ice that break off an

ice shelf & drift into the oceanCrevasse- a large crack that forms where the

glacier picks up speed or flows over a high pointGlacial drift- the general term used to described

all material carried & deposited by glaciersStratified 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

 

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.

There are main types of glacial deposits stratifiedtill

some 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.

Gravity’s Effect on Erosion & DepositedMass 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 movementMudflow-a rapid movement of a large mass of

mudCreep- the extremely slow movement of

material down slope

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 rapidly

Rock falls, landslides, and mudflows are all types of rapid mass movements

Slow mass movement- happen little at a timecreep is an example