Erosion and Deposition

Before we begin… Write down the following questions. You will answer these as we go through the powerpoint.

1. What is erosion? What is deposition?

2. What are the four agents that cause erosion?

3. What is the most influential agent of erosion?

4. What different landforms can streams create?

5. What is created when the roof of a cave collapses?

6. How are sea caves, sea arches, and sea stacks created?

7. How does wind erode rocks?

8. Name three things that gravity can cause due to erosion.

9. How do glaciers cause erosion?

Erosion and Deposition

Erosion- process that moves weathered sedimentsfrom one place to another

Deposition- the dropping of sediments that havebeen eroded

Sediment- The tiny grains of broken down rock

Erosion and deposition are two parts of the same process.

Erosion only occurs when there is enough energy to carry the sediments. Deposition occurs when the energy decreases.

There are four main forces that causeerosion and deposition:

1. Gravity

2. Running Water

3. Glaciers

4. Wind

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Water

The most influential force of erosion is water due to its ability to move materials from one location to another and its vast presence over earth.

Examples include bodies of water such as rivers and streams.

Water

Rivers and streams in the landscape cause erosion and deposition and constantly shaping the land.

Moving water works with gravity to affect the landforms that the water makes.

Channel- the path that a stream follows due to the erosion from water on soil and rock. As the channel gets wider and deeper, canyons and valleys can form.

Floodplains

When a stream floods, a layer of sediment is deposited over the flooded land. Many layers of deposited sediment can form a flat area called a floodplain.

Delta

When a stream empties into a body of water, such as a lake of an ocean, its current slows and deposits its load. Streams often deposit their load in a fan shaped pattern called a Delta.

Alluvial Fan

Alluvial fan is a fan-shaped deposit that forms on dry land when a stream flows onto a flat land surface from mountains or hills.

Groundwater

Groundwater is the water located within the rocks below earth’s surface.

Slightly acidic groundwater can cause erosion by dissolving rock leading to the formation of caves

Sinkhole- occurs when the roof of a cave collapses, leaving a circular depression.

Sinkhole Current Event Link

http://www.cnn.com/2013/11/14/us/florida-sinkhole/

What forces shape a shoreline?

Waves play a major part in building up and breaking down a shoreline.

The first parts of the shoreline that waves meet are the headlands. The waves slowing waves bend towards the headlands, which concentrates the waves energy. A huge amount of energy is released when waves crash into headlands, causing the land to erode.

What coastal landforms are made by erosion?

Sea cliff- a cliff that is formed when waves strike a cliff’s base, wearing away the rock.

Sea Caves, Arches, and Stacks

As the rock making up sea cliffs erodes, it breaks and cracks. Waves can then cut deeply into the cracks and form large holes that continue to erode, which are known as sea caves.

Sea arch- A sea cave that has eroded even further.

Sea stacks- isolated rock that forms when the tops of sea arches collapse.

Wind

Wind can erode rocks over a long period of time.

When wind blows sand and other particles against a surface, it can wear down the surface over time.

The grinding and wearing down of rock surfaces over time is known as abrasion.

Gravity

Gravity works with other agents of erosion and deposition which can result in landslides, mudslides, and sinkholes.

The force of gravity can move water and ice and make rock, soil, snow, or other material move downhill.

Glacier A glacier is a large mass of moving ice that forms by the

compacting of snow.

As glaciers move due to gravity, they pick up materials that become embedded in the ice. As the glacier moves forward, the materials scratch and abrade the rock and soil underneath the glacier, causing more erosion

Glaciers are also agents of deposition. When a glacier melts, it drops materials that it carried.

A Glacial drift is the term for all of the materials carried and deposited by a glacier.

Alpine glacier- A glacier that forms in a mountainous area

Glaciers