Weathering and erosion

Mason Malan

What is weathering?

Weathering is the process of breaking down rock by physical/mechanical weathering, chemical weathering and biological weathering.

Physical/mechanical weathering

When rocks heat up then cool down they expand and contract after repeatedly going through this process they can crack. Wind can also break down rocks by blowing particles in the wind and scraping them against rocks wearing them down. Water can also weather rocks. There is something called frost wedging also which breaks rocks apart by the process of freezing and thawing because when water freezes it expands.

Chemical weathering

Chemical weathering can be caused by acid rain that can soak into the ground then acid wear down rocks forming caves. Also when water breaks down into H positive and OH negative ions it can react with rocks and create new substances. Oxidation is an example and happens when oxygen combines with rock and its elements and forms other kinds of rock. Carbonation can occur when carbon dioxide reacts with some rocks and makes a solution which can be taken away by water.

Biological weathering

Biological weathering is the process of animals, plants or any living thing breaking down rocks by animals burrowing , plants roots growing between rocks causing them to crack. The most common one is weathering by plant roots that grow deep in the rock looking for water and nutrients and then crack it.

What is erosion?

Erosion is the transportation of weathered rock and sediments from place to place by wind, water, gravity and glaciers.

Erosion by wind

Wind erosion is when it picks up and carries tiny particles like sand and dirt and moves it around. It happens when the strength of the lifting air is able to lift up the object and exceed the gravity of the particle on the surface.

An example is sand dunes which wind erosion can create and destroy them. Another example of wind erosion are rock formations in deserts which wind moves air through to change the structures.

Erosion by water

Water erosion is when water such as a river or rain detaches and removes soil or sand wearing it away from the earths surface and transports it to another area. The erosion can change the shape of a coast line quickly. Or erosion can change the landscape very slowly like when the Colorado River carved out the Grand Canyon.

Erosion by gravity

Erosion by gravity can be caused indirectly by rain or flowing water and glaciers because it pulls debris downhill by the force of gravity. Erosion can also be caused directly by gravity by pulling rocks, mud, or soil down hills. Landslides are caused by gravity and can be very dangerous and cause a lot of damage. Gravity can also create many landforms with the help of ice, wind and water by pulling rock and soil downward.

Erosion by glaciers

Erosion by glaciers is the movement of large masses of ice that can change the landscape by making mountains and creating valleys. The glaciers will leave behind deposits of particles of all sizes when it melts and also creates lakes this way. There are landforms called moraines that are areas with many rounded hills that contain rocks and soil that built up at the edges of glaciers.