Download Plate Tectonics

Plate Tectonics
Inner core: Super-hot but solid
Outer core: Melted iron and nickel (liquid)
Mantle: Silicon, aluminum, iron, magnesium,
oxygen, and other elements (liquid)
Crust: Rocky shell (from between 2-75 miles thick)
Continental Drift Theory
The theory that the continents were once joined
as a supercontinent (Pangea) and have drifted
apart over millions of years.
What is the evidence?
*The plates only move about 1 inch per year.
Help For Gondwanaland assignment
Prince Harald
Wilhelm II
Oates
Types of colliding & spreading
1. The Himalayas are forming from two
continental plates colliding and pushing up.
Types of colliding & spreading
1. The Himalayas are forming from two
continental plates colliding and pushing up.
2. The Andes are being formed by subduction
where an oceanic plate slides under a
continental plate causing volcanoes that create
mountains.
Types of colliding & spreading
1. The Himalayas are forming from two continental
plates colliding and pushing up.
2. The Andes are being formed by subduction
where an oceanic plate slides under a continental
plate causing volcanoes that create mountains.
3. Accretion is where an oceanic plate comes
together with a continental plate and levels off
seamounts (underwater mountains) piling up debris
in the trench. This causes a slow expansion of a
continent outward – U.S. west of the Rockies.
Tsunamis (massive waves triggered by
earthquakes) can be caused by subduction.
Banda Ache, Indonesia- around 250,000 killed from
waves 100 feet tall.
Divergent Plate Boundaries
Spreading (divergent plate
boundaries) is where two
plates pull apart resulting in
a “rift.” This allows magma
to rise creating new land.
Ex: Mid-Atlantic Ridge
(longest mountain range)
Faults
Where two plates slide past each other, often
getting stuck and then slipping causing an
earthquake.