Transcript PLATE TECTONICS - Middletown High School

Warm-Up
Find the mistakes!
1. During the 1940s and 1950s, scientists began using radar on moving
ships to map large areas of the ocean floor in detail.
2. The youngest rocks are found far from the mid-ocean ridges.
3. The scientist Harry Henry Hess invented echo-sounding devices for
mapping the ocean floor.
4. As the seafloor spreads apart, hot saltwater moves upward and flows
from the cracks.
5. Rocks on the seafloor are much older than many continental rocks.
PLATE
TECTONICS
Theory of Plate Tectonics
Earth’s crust and part of the upper
mantle are broken into sections.
These sections are called plates.
Plates move on the asthenosphere: a
plastic-like layer of the mantle.
Earth’s Structure
Earth’s Crust & Mantle
Plates are made up of the crust and a part
of the upper mantle:
Lithosphere- Rigid. Made up of crust and
upper mantle. 0-100 km thick.
Asthenosphere- The plastic-like layer that
lies below the lithosphere.
The plates of the lithosphere float on the
asthenosphere.
Divergent
Plates are
moving apart
from each other
Creates new
seafloor and
expanding
oceans
As continental
plates separate,
they create a rift
valley
As oceanic
plates separate
and magma
rises, ridges
form
Mid Ocean Ridge
North American
Plate
South
American
Plate
Eurasian Plate
African Plate
Convergent
Plates move together
There are two things that can happen at a
convergent plate boundary…
Oceanic - Continental
 At sites where oceanic and
continental plates collide,
subduction zones form.
 At subduction zones, the
more dense plate (oceanic)
sinks beneath the less dense
plate (continental).
The sinking plate melts and
forms magma that rises to
the surface through a
volcano.
Mountains and deep sea
trenches are also found at
subduction zones.
The Andes
Mountain Range is
found in Chile.
The volcanism of the
Andes Range is a result
of the subduction of the
Nazca Plate underneath
the South American
Plate.
Continental - Continental
As continental plates collide, mountain
ranges are created.
The Himalayas are
still forming as the
Eurasian and Indian
Plates collide.
Transform
 Plates slide past each
other
 As one plate slips past
another suddenly,
earthquakes occur.
San Andreas Fault
Located in California
The Pacific Plate is
sliding past the
North American
Plate
On the split screen Notes
Draw a picture of the Earth’s LayerLabel and explain a convection current
Why Do The Plates Move?
The transfer of heat inside the Earth provides the
energy to move plates and, subsequently, many
of Earth’s surface features.
 Convection currents inside the mantle causes
the movement of the plates
Convection Currents
The Earth’s hot, inner core heats the
liquid mantle.
The magma closest to the core heats
up, becomes less dense, and rises.
The magma at the top of the mantle
cools, becomes more dense, and sinks.
Graphic organizer
 Create a three flap flip chart
 In the front of each flap write the name of a type of
boundary: Transform, Divergent, Convergent
boundaries
 Draw and color the boundaries on the inside of the
front flap
 Use your book and notes to write the following
information under each flap:
 What happens at this type of boundary
 What types of geographic formations does it create
 Where in the world can this boundary be found