How Water Shapes the Earth

1
How Water Shapes the Earths Surface

• Chapter 10.4 pages 386 - 397

2

• Weathering and erosion are the 2 main processes
  by which water breaks down Earths landscapes.
• Deposition is the process by which water builds
  up features in the landscape.

3

• A. Weathering breaking rock down into smaller
  pieces
• When rock is broken down into tiny pieces it is
  called sediment.
• Weathering can take thousands of years
• There are main 3 kinds of weathering

4
Physical Weathering - water gets into cracks in
rock, freezes and expands, breaking the rock
apart. This is also called frost wedging
5
Chemical Weathering - chemicals in the air slowly
weaken the rock so it breaks into small pieces
6
Biological Weathering - plants release chemicals
that slowly dissolve the rock they grow on
7
How Caves Are Formed
8
(No Transcript)
9

• In limestone rocks (made of calcium carbonate)
  chemical weathering of underground rock can
  create caves.
• Water and carbon dioxide in the air combine to
  form a weak acid which seeps into the ground and
  slowly dissolves the rock over thousands of
  years.
• underground streams transport the dissolved rock
  away, leaving a hollow space

10
When a cave forms close to the surface, a
sinkhole may form.
11
A landscape with many caves and sinkholes is
called a Karst
12

• B. Erosion pieces of weathered rock are
  transported away from their original location
• Erosion is said to carve the landscape.
• Erosion can be fast or slow
• There are 4 main transporters (called agents of
  erosion)

13
Water - running water carries sediment away.
14
Rivers in mountainous areas carve steep valleys
that have a V-shape.
15
Wind - strong winds can carry exposed soil away
16
Gravity - mountains gradually crumble as gravity
pulls rocks down.
17
The sudden rapid movement of rock material down a
mountain is called an landslide.
18
Ice - glaciers carry rocks and boulders with them
when they move, then drop them when they melt.
19
How Glaciers Shape the Landscape
20
When glaciers move, they leave scratch marks
(called striations) on the rock
21
Glaciers are so huge that they can carve out
whole valleys. These valleys have a U-shape.
22
A hanging valley is a small U-shaped valley cut
off by a bigger valley created by a bigger
glacier
23
A cirque is a bowl-shaped valley at the head of a
glacier
24
An arete is a narrow ridge between two cirques
25
A horn is a pyramid-shaped peak between three
cirques
26
A fjord is a narrow ocean inlet carved by a
glacier
27

• C. Deposition eroded sediments and other
  materials are deposited by water or ice, building
  up the landscape.

28
A delta is an area of built-up sediment dropped
when a river empties into an ocean or a lake. It
is usually triangular or fan-shaped.
29
(No Transcript)
30
A moraine is a ridge of rocky material left by a
glacier
31
An erratic is a large boulder left behind by a
glacier.
32
The Effects of Global Warming on Glaciers All
over the planet, glacier have receded (shrunk)
in the past 100 years.
33
Mount Kilimanjaro in 1993...
34
Mount Kilimanjaro in 1993...
35
... and in 2000.
36
... and in 2000.
37
McCall Glacier in 1958...
38
... and in 2003