2. 2 Weathering, Erosion, Deposition, and Landscapes Weathering – the breakdown of rocks into smaller pieces, called sediments. Erosion – the process where the sediments are transported by wind, gravity, glaciers, and running water. Deposition – the process whereby these sediments are dropped by their transporting agents. Weathering breaks down the rocks, erosion moves the particles, and deposition drops the sediments in another location.

3. Erosion:  Gravity is the main force causing erosion Deposition:  Can be moved by wind or flowing water Weathering Χ Can be physical or chemical Χ Has to happen before erosion. The rocks have to be broken into smaller pieces before they can erode away.

4. 1. Release of Pressure 2. Freezing & Thawing 3. Animal Actions 4. Plant Growth

5. Root/Plant Wedging/Action Ice/Frost Wedging/Action Rusting Action WEATHERING

6. Release of Pressure Χ As the surface of a rock is eroded, the rock begins to release pressure. Χ Causes top layers of the rock to crack and flake off.

7. Freezing & Thawing When water in the cracks of rocks freezes it expands causing the crack to enlarge or get bigger. The ice melts & refreezes over & over, breaking the rock apart.

9. Animals dig (burrow) through the ground to make their homes. This loosens the soil & breaks apart rocks.

10. Plants roots can grow into cracks in the rock, slowly breaking them apart.

11.  Moving water causes much of the erosion that shapes the Earth’s surface  Sediments that have been transported through running water appear rounded and smooth and are deposited in sorted piles.  Water can deposit materials in other places to create new landforms.  Sediments are deposited in sorted piles.

12.  Can loosen sediments and carry them away  Can cause flooding  Damages soil, roads, and buildings

13.  Cause erosion along coastlines  Sand in the waves acts like sandpaper  Weathers away rock  Grasses and plants can help hold soil in place

14.  Gravity pulls glaciers down along a valley  Grind rocks beneath them into sediments  Over a long time, creates a U shaped valley

15.  Gravity causes rivers to flow  Carry sediments  Rock, sand, and soil  Deposited materials found at the bottom of cliffs or steep slopes  Can form deltas  Appear angular and unsorted.

16.  Caused by wind blowing dust, soil, or sand from one place to another  Sediments appear pitted (random holes) and frosted (glazed look) and are deposited in sorted piles  Only very small particles can be transported by wind.  Changes sand dunes and fields  Sediments are deposited in sorted piles.

17.  Large, loose deposits of sand  Size and shape depend on speed and direction that winds are blowing  More common in drier landscapes  Easier for particles to move through the air  Less plant life to hold down soil

18.  Bare, plowed fields can become dry  Winds blow topsoil off fields  Farmers plant trees along edges of fields to stop wind  Less they plow, less erosion