weathering & Erosion -hailey

Weathering & Erosion

by Hailey Saunders

Erosion moves the sediments to other locations by water, wind, and gravity.

Erosion

weathering is the process by which rocks are broken down into sediments slowly over time.

Weathering

weathering breaks down rocks into smaller pieces, called sediments. Mechanical weathering changes the shape and size of a rock, but it doesn't change the rock's chemical composition. Wind and water are the two main agents that cause mechanical weathering. other agents are living things and temperature changes.

Mechanical Weathering

Chemical weathering breaks down rocks through chemical processes that change the rock's chemical composition for example, when carbon dioxide in air dissolves in rainwater, carbonic acid is formed, this can dissolve some rocks

​​Chemical Weathering

​Flowing water is an important agent for erosion. It can carry rocks, sediments, and soil downstream. Rocks can scrape against each other causing mechanical weathering at the same time as erosion.

Flowing water

​Glaciers can also cause mechanical weathering, ripping chunks of rock out of the ground as they move across land, rocks caught in a glacier are carried along the glaciers path causing erosion.

Glaciers

wind can usually carry smaller sediments that can scrape against rocks and cause weathering at the same time as erosion.

​Wind

Gravity constantly pulls water, ice, rocks, and sediment downhill. Many rocks break as they erode downhill, causing additional mechanical weathering.

Gravity

​Agents Of Erosion

​Differential weathering

​Differential weathering is when a region contains many rock types, some that are more resistant to weathering and some that are not as resistant. causing the less resistant rocks to weather away while the more resistant rocks will take longer to break down which can leave layers of highly resistant rocks and holes or spots where less resistant rocks have been broken down.

Water can weather rocks by getting into cracks and freezing, when the water freezes it expands causing the rocks to push apart.

Ice, Plants, and Changes in Temperature Can Break Rocks

​Plants growing in the cracks of rock can also push apart rocks in a similar manner to how water can break rocks.

​Changes in temperature from fire or volcanic activity can also cause rocks to crack or break down as they expand and contract from heating and cooling.

once rocks and sediments stop moving after they get eroded somewhere else. This process is called Deposition. When sediment sare eroded they are deposited in horizontal layers called strata. The oldest layer of sediment is at the bottom and mor recent deposits are at the top.

​​Deposition

As a river flows into the ocean, sediments carried by the flowing water begin to pile up around the mouth of the river. These sediments create deposits of land, called Deltas. Delta's are good places to farm because the soil contains a lot of nutrients picked up along the river's path to sea.

Delta

Multiple Choice

what is the movement of sediment?

• Erosion

• weathering

• Deposition

• Delta

Multiple Choice

what is deposition?

• the process of which sediment gets dropped into a new place after being eroded

• the process of which rocks are broken down into smaller pieces called sediment

• the process of which rocks are moved by water, wind, gravity, and glaciers.

Multiple Choice

can weathering happen at the same time as erosion?

• yes

• no

Multiple Choice

what are the 4 main agents of mechanical weathering?

• wind, dirt, sand, and gravity

• water, glaciers, wind, and oxygen

• water, glaciers, gravity, and wind

• water, wind, gravity, and the sun

Multiple Choice

what is delta?

• Delta is the sediment pile that flows from the river into the ocean.

• delta is what rocks are called after they get chemically weathered

• delta is what rocks are called after they are mechanically weathered.

• delta is what sediments are called when they are being eroded by wind