Erosion and deposition

What evidence of erosion do you see in this picture? The process by which water, ice, wind or gravity moves fragments of rock and soil. What evidence of erosion do you see in this picture?

Deposition Deposition is a constructive process in which sediment settles out of water or wind, or is laid down, and creates new landforms.

Erosion is Movement of Sediment! This process, known as Erosion, is gradually wearing down the surface of the earth. Erosion is the process by which weathered rock and soil (sediment) are moved  from one place to another. Erosion carves the Earth's surface creating canyons, gorges, and even beaches. What do you think has caused this rock to look this way?

The intensity of wind erosion is determined by: As the wind blows it picks up small particles of sand/sediment and blasts large rocks with the abrasive particles, cutting and shaping the rock. The intensity of wind erosion is determined by: Sum (amount) Speed Slope Surface

Wind Erosion Creates sand dunes Greatest impact in deserts Removes fertile topsoil

Water Causes Erosion runoff, rivers and, streams Creates MOST of the changes in the Earth's landscape!

Water causes Erosion When rain falls to the Earth it can evaporate, sink into the ground, or flow over the land as Runoff. When it flows over land, erosion occurs. Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land. Rivers and streams are a constant flow of runoff- they constantly weather and erode!

How much erosion takes place is determined by the: Water causes Erosion How much erosion takes place is determined by the: Sum (amount) Slope Speed Surface The 4 S’s

Ice Causes Erosion Glaciers wear down the landscape; by picking up and carrying debris that moves across the land along with the ice.

Ice Causes Erosion Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses. Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!

**Sum (Glaciers are massive!) Ice Causes Erosion How much erosion takes place is determined by the: **Sum (Glaciers are massive!) Slope Speed Surface

Gravity causes erosion Creep, Slump, Landslides, Mudslides, and Avalanches. Slower Faster These are examples of mass movement (or called mass wasting) landslide clip.mpeg

Gravity causes Erosion How much erosion takes place is determined by the: Sum **Slope Speed **Surface

Plants CAN PREVENT erosion

Together, Erosion and Deposition build new landforms. Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere else Deposition is the process by which sediments (small particles of rock) are laid down in new locations. Together, Erosion and Deposition build new landforms. Deltas Canyons Meanders Floodplains

Delta Where rivers meet the ocean is called the mouth of the river. Soil and dirt carried by these rivers is deposited at the mouth, and new land is formed. The new, soil-rich land is known as a Delta

Canyons are large valleys created by a river or stream. This simple animation provides you with a visualization of how the Colorado River has "downcut" into the rock layers of the Grand Canyon. How long it took to carve the Grand Canyon is debated by geologists. Some estimates are between 6 and 8 million years, which is very recent by comparison. Canyons are large valleys created by a river or stream.

This constant motion creates a series of S-shaped “loops”. Meanders Meandering streams wander side to side as they constantly seek out the lowest elevation. This constant motion creates a series of S-shaped “loops”.

Meanders Stream Velocity varies from one side to the other side of the “S”, resulting in erosion in some places and deposition of sediments in others.

Floodplains Floodplains form along the banks of mid-order streams and larger rivers. These are low-lying areas along the sides of a river channel that have regular times of heavy waterflow to cause the river to spill over and flood the land.

Discussion What are some factors that affect the rate of erosion? Weather, climate, the shape of land (topography), and type of rock affect the rate of erosion. How are erosion and deposition related? When agents of erosion slow down, some sediment can fall out of wind or water and be deposited.

Challenge How can erosion affect the shape of sediment? As rock fragments are eroded, they bump against each other, which can change the shape from poorly rounded to well-rounded. How can erosion sort sediment? Sediment that is eroded over a short distance is poorly sorted, with grains of different sizes. As sediment erodes over a longer distance, it becomes moderately sorted (with grains of a small range of sizes) and then well-sorted (with grains of all about the same size).