Erosion and Deposition

1
Erosion and Deposition

• Erosion is the process by which weathered rock
  and soil particles are moved from one place to
  another.
• Deposition Sediments are laid down in a new
  location.

2
Five Factors of Erosion

• Gravity
• Wind
• Running Water
• Glaciers
• Waves

3
Gravity

• Mass Wasting- the downhill movement of sediments
  caused by gravity.
• Landslides
• Mudflows

4
Slump

• A block of Rock or soil moves down a steep slope
  with its upper surface tilted backwards as it
  falls

5
Slow Mass Wasting

• Earth Flows and Soil creep are two examples of
  slow mass wasting

6
Wind Erosion

• Deflation Wind removes loose materials such as
  sand, silt and clay
• Abrasion Sand Blasting

7
Features formed by Wind Erosion

• Dunes Wind blown sand is deposited near rock
  and bushes in desert areas
• Loess Very fertile, light in color, many meters
  thick consisting of sand and silt

8
How can you curtail wind erosion?

• Bushes, trees and fences act like barriers to
  block the wind

9
Major Cause of Erosion

• Running Water Water turns into runoff as it
  travels, picking up weathered rock particles and
  making small grooves in the ground known as
  Rills. As the Erosional process continues, the
  grooves become larger and are now called
  Gullies.

10
Factors that affect Runoff

• Amount of rainfall
• Plant Growth
• Shape of the Land

11
Life Cycle of a River

• Immature River Early stages of development
• Mature River In development for thousands of
  years

12
Life Cycle of a River

• Meandering A river begins to curve and wind due
  to erosional forces

13
Oxbow Lake

• Large U shaped bends forming small lakes

14
As a river leaves a mountain and runs out onto a
flat plain its speed decreases and its sediments
are spread out in a fan like shape called an
Alluvial Fan
15
Delta - large amounts of sediments deposited at
the mouth of a river that flow into a lake or
ocean
16
Rivers overflow their banks after heavy periods
of rain or thaw And leave fine sediment deposits
17
Levees are formed from larger particles that
settle of the sides of rivers
18
Glacial Ice erodes away rock as it moves by
abrasion and plucking away at the rock beneath
it
19
Rocks and soil that are deposited by the glacier
are called Till
20
After a Glacier melts and retreats, it leaves
behind till, which forms a ridge called a
Moraine
21
An oval shaped mound of Till is called a
Drumlin
22
Melt water deposits are left by a Valley Glacier
stops moving
23
Out wash Plains are fan shaped and formed In
front of a Terminal Moraine
24
As a Iceberg melts it leaves its deposits on the
Ocean Floor
25

• Kettle Lakes (Great Lakes)
• form in two ways
• Glacial Till deposits form in river
• channels causing water to form
• lakes
• Blocks of ice melt away leaving
• sediments behind and a
• depression forms after the
• ice melts