1. Erosion by Runoff
Moving water is the major agent of erosion that has shaped Earth’s land surface.
Runoff- water that moves over land that can carry soil particles with it.
Amount of runoff depends on:
Amount of rain area receives
Vegetation
Type of soil
Shape of land
How people use land
More runoff = more erosion
Factors that reduce runoff will reduce erosion

2. Very few plants to absorb the water
How is it possible for deserts to have high runoff and erosion with such little rainfall they receive?
High number of plants to protect soil
How is it possible for wet areas to have little runoff and erosion?

3. Erosion by Rivers
Through erosion, a river creates valleys, waterfalls, flood plains, meanders, and oxbow lakes.

4. Erosion by Rivers

5. Erosion by Groundwater
Not all precipitation that falls will evaporate or become runoff precipitation can soak into the become groundwater
Carbon dioxide dissolves in groundwater and produces a weak acid called _____________ _________.
The acidic groundwater breaks down limestone by flowing into cracks and eventually hallowing out the rock.
Over long periods of time this can form caves.
Stalactite- deposit that hands from the roof
Stalagmite- slow drippings build up as cone-shaped deposits from the cave floor

6. Glacier- large mass of ice that moves slowly over land
Glaciers
Glacier- large mass of ice that moves slowly over land
Continental Glacier- covers much of a continent or large island
10% of Earth’s land- Antarctica and most of Greenland
Spread out like pancake batter in a frying pan
Valley Glacier- long, narrow glacier that forms when snow and ice build up high in a mountain valley.
Slides of mountains keep these glaciers from spreading in all directions
Move down valleys that have been cut by rivers.
Smaller than continental
Glaciers can only form in areas where more snow falls than melts
Most move just a few cm- a few m per day

7. Valley Glacier
Continental Glacier

8. Erosion by Glaciers
Glaciers erode the land in two ways: plucking and abrasion.
Plucking- as glacier flows over land it picks up rocks
Weight of glacier can break apart rock  rocks get stuck to bottom and move along with glacier
Abrasion- rocks on the bottom of glaciers drag across land and scratches the bedrock

9. Glacier Movement and Abrasion
Can start video at 1:00

10. Glacier in Argentina known as White Giant collapsed on March 10, 2016