Table of Contents

Mass Movement

Water Erosion

Glacial Erosion

Wave Erosion

Wind Erosion

Human Activity and Erosion

Erosion and Deposition

pg. 348-357

pg. 358-363

pg. 364-367

pg. 344-347

pg. 368-371

pg. 372-377

Mass Movement

Cycle of Erosion and Deposition

Erosion is the process by which weathered rock and soil, or sediment, is moved from one place to another.

Deposition occurs when erosion deposits, or lays down, the sediment.

Mass MovementMass Movement

Gravity is the force that pulls objects downward (towards the Earth). Gravity also causes mass movement of sediment. It can occur rapidly or slowly.

The different types of mass movement include landslides (when rock and soil slide quickly down a steep slope), mudflows (the rapid downhill movement of water, rock, and soil), slump (when rock and soil suddenly slips down a slop in one large mass), and creep (the very slow movement of sediment).

Match the Mass Movement type with the correct diagram.

Creep

Slump

Landslide

Mudflow

• Glaciers are any large mass of ice that moves slowly over land. They can only form in areas where more snow falls than melts.

• Continental glaciers can flow in all directions as they move and they cover much of a continent or large island. Today, continental glaciers cover about 10% of Earth’s land.

• Valley glaciers are long, narrow glaciers that form in the valley of mountains. They can move at a rate of a few centimeters to a few meters a day.

• When glaciers move they pick up huge rocks and small sediment. Cuts and scratches, also called abrasions, in bedrock are evidence of glacial movement.

Glacial Erosion

Valley GlaciersWhen glaciers recede, they leave behind evidence of their existence.

Glacial Erosion

Wave Erosion• Energy in waves comes from the wind. • Waves shape the coast through:oerosion by breaking down rock causing headland, sea arches, sea stacks, caves, and wave-cut cliffs.

odepositing sediment, forming coastal features such as beaches, sandbars, barrier beaches, and spits.

Wave Erosion

Wave Erosion

Page 366-367What are the different landforms called? Were they formed by erosion or deposition?

Wind Erosion

Wind ErosionWind can be a powerful force in shaping the land, especially where there are few plants to hold the soil in place. The wind causes erosion through deflation, the process by which wind removes surface material. It moves particles in three ways.

Which of the words--fine, medium, or large--correctly begins each sentence?

Wind erosion and deposition may form sand dunes. Sand dunes are where wind-blown sediment has build up. They can come in many shapes and sizes. Sand dunes move over time and are shaped according to the wind direction. Plant roots can help anchor dunes in one place.

Wind Erosion

Human Activity and Erosion

Mining, logging, agriculture, and the development of land cause erosion and deposition. Strip mining is the process of scraping away vegetation and topsoil above minerals close to Earth’s surface. Clear-cutting is a process in which every tree in a large section of forest is cut down at once.

Water Erosion

Factors Affecting Runoff

When water moves over the land, it carries particles with it. This is called runoff. Runoff factors include the amount of rain in the area, the type of vegetation on the land, the soil type, the topography or shape of the land, and human usage in the area.

River Formation

Rivers begin when many small streams come together (called tributaries) into a main river. As the river flows over flat land, or the flood plain, and slows down, meanders or loop-like bends in the river form.

Sediment deposited where a river flows into an ocean or lake, also known as the river mouth, builds up a landform called a delta.

Water Erosion

Oxbow Lakes

In a meander, water on the inside of the bend flows slower than that of the outside which deposits sediment, increasing the side or shape of the meander. Sometimes oxbow lakes can form from a meander that has been cut off from a river.

Water Erosion

Water DepositionDeposition creates landforms such as the Mississippi River delta.

Water Erosion

Mississippi River Drainage Basin

• World’s 3rd largest watershed drainage basin

• Covers more than 1,245,000 square miles

• Includes all or part of 31 states and 2 Canadian provinceso41% of the United

States

Human Activity and ErosionMapping Louisiana Coastal Erosion

Louisiana’s coast has lost about 55 square kilometers of wetlands per year over the last 50 years. It is predicted that an additional 1,127 square kilometers of land will be lost in the next 50 years.

Human Activity and Erosion

Changing WetlandsThe graph shows changes in coastal Louisiana wetland area over the past 6,000 years. Based on the data in the graph, what do you think might happen to the wetlands in the next hundred years?