Transcript World Geog Ch 1_lesson2

World Geo 3200/02
Unit 1 : LESSON 2
A Review from last day…….
The Structure of the Earth & Continental
Drift
Structure of the Earth’s Surface
 Topography is a
general term referring
to the surface
features of the earth
like, hills, mountains,
valleys, plains,
plateaus and other
relief features.
Structure of the Earth’s Surface
Structure of the Earth’s Surface
Structure of the Earth’s Surface
Structure of the Earth’s Surface
Structure of the Earth’s Surface
Structure of the Earth’s Surface
Review
Observing the elevation profile below
which province would be least likely to
have extensive plains?
Review
Imagine you flew from the west coast of
South America to the east coast and you
flew right along the equator. What land
forms would you fly over?
How Landforms Change: Plate Tectonics
p.10
This section introduces you to Alfred
Wegener and J. Tuzo Wilson
Main idea
Evidence
Flaws (if any)
Video Link
Plate Tectonics
 Tectonic plates move or float on top of the
asthenosphere (orange in the figure). However
they do not float freely. The plates are forced in
specific directions by the flow of magma
beneath. Just like a boat caught in a current
plates move with the flow of magma. The
magma forms convectional currents. The
magma closer to the core heats and then rises
towards the surface as its density decreases.
Once the rising magma reaches the lithosphere
it moves in opposite directions.
Plate Tectonics
Plate Tectonics
Plate Tectonics
Plate Tectonics
Compressional Forces occur where two
tectonic plates come together. They
compress against each other.
Subduction Zones sometimes occur
where compressional forces result from
two plates colliding.
Tensional Forces occur where two
tectonic plates are pushed apart. The
tension is created as the plates move
away from each other.
Ridge Zones sometimes occur where two
plates move apart. The magma rises
between the plates and forms a ridge.
Compressional Forces occur where two
tectonic plates come together. They
compress against each other.
Subduction Zones sometimes occur
where compressional forces result from
two plates colliding.