Changing Earth’s SurfaceThe wearing down of Earth’s surface is called

erosion.

Erosion is the process by which natural forces move weathered rock and soil from one place to another.

Causes of Erosion-gravity-running water-waves-glaciers-wind

Building Up Earth’s SurfaceThe material moved by erosion is

sediment.

-can consist of rock, soil, or remains of plants and animals

-produced be erosion and weathering

Deposition occurs where the agents of erosion deposit or lay down sediment.

-changes the shape of the land

Erosion and deposition act together in a cycle that wears down and builds up Earth’s surface.

Erosion and deposition are at work everywhere on Earth.

As a mountain wears down in one place, new landforms build up in other places. The cycle of erosion and deposition is never-ending.

Erosion occurs constantly, even while mountains are forming

Erosion wears down mountains and fills valleys with sediment.

Working together, erosion and deposition have almost leveled the land surface

When new mountains or plateaus form, the cycle of erosion begins all over again.

Cycle of Erosion & Deposition

Mass Movement

Gravity is the force that pulls objects toward the center of the Earth.

Gravity is the force that moves rock and other materials downhill.

Gravity causes mass movement.

Mass movement is any one of several processes by which gravity moves sediment downhill.

Mass movement can be rapid or slow.

Landslides

-Most destructive type of mass movement

-Occurs when rock and soil slide quickly down a steep slope

Types of Mass Movement

http://www.youtube.com/watch?v=L12JeAz9YN0

-Rapid downhill movement of water, rock, and soil

-Can contain up to 60% of water

-Often occur after heavy rains

-Can occur on gentle or steep slopes

Mudflow

-A mass of rock and soil that suddenly slips down a slope in one solid mass.

-often occurs on a steep slope when water soaks the bottom of clay rich soil

Slump

Creep-The very slow movement of rock and soil.

-can occur on gentle or steep slopes

-occurs from the freezing and thawing of water in cracked layers beneath the soil

Types of Mass Movement

Speed Slope

Landslide

Mudflow

Slump

Creep