Erosion and Weathering

What is erosion? (geology) the mechanical process of wearing or grinding something down (as by particles washing over it) The wearing away of the earth’s surface by natural processes corrosion: erosion by chemical action

Types of Erosion Water Wind Glacier Soil Sea

Water Occurs from chemicals in the water and the force and flow of water Chemicals break down certain rocks like limestone or chalk Force of water creates cracks and crevasses These get bigger and bigger as it gets eroded, particles of the rock get carried in the water and further aid erosion

Wind The wind picks up smaller particles of rock (pebbles and sand) These hit landforms and take pieces off them This friction causes the break up of landforms

Glacier Erosion What is a GLACIER?: A huge mass of ice slowly flowing over a land mass, formed from compacted snow in an area where snow accumulation exceeds melting These large bodies of ice that pick up rocks and earth and erode the earth’s surface Powerful eroding machine, picking up pieces of rock the size of houses in some places Glaciers are so powerful they can carve valleys and create landforms

Sea Erosion Salts and other chemicals in the water erode coastal rocks These are dragged out to sea and deposited in other areas (Long shore Drift) Wave power creates erosion. Also particles of rock and sediment aid to the erosion process

Soil Erosion Biggest problem for farmers Wind and rain remove topsoil and nutrients Makes the soil infertile and it breaks up leaving dongas

Deposition

Definition Deposition- the process in which sediment is laid down in new locations –The end result of erosion

Water Deposition Alluvial fan- fan shaped deposit of sediment on land –Usually form when a stream slows down and enters a flat plain Delta- sediment from a stream deposited where a river enters a large body of water –Triangular shape

Alluvial fan and Delta

Glacial Deposition As a glacier melts, it creates landforms by depositing its sediment load –Till-unsorted mixture of sediment containing fragments of various sizes –Moraine-mounds of sediment at the downhill end of the glacier and along its side Long Island is a glacial moraine

Till and Moraines

Wind Deposition Sand dunes- large deposits of sand dropped from wind –Sand dunes can move as the wind picks up sand from the back of the dune and blows it to the front

Sand Dunes