Download Plate Tectonics - East Hanover Township School District

1 - Earth’s Layers
The Earth's rocky
outer crust solidified
billions of years ago,
soon after the Earth
formed.
This crust is not a
solid shell; it is
broken up into huge,
thick pieces (Plates)
that drift on top of
the soft, underlying
mantle.
2 - The Crust
• Outermost layer
• 5 – 100 km thick
• Made of Oxygen, Silicon, Aluminum
3 - The Mantle
• Layer of Earth
between the crust
and the core
• Contains most of the
Earth’s mass
• Has more
magnesium and less
aluminum and
silicon than the crust
• Is denser than the
crust
4 - The Core
• Below the mantle
and to the center of
the Earth
• Believed to be mostly
Iron, smaller
amounts of Nickel,
almost no Oxygen,
Silicon, Aluminum, or
Magnesium
5 - Plate Tectonics
The Earth’s crust is broken into pieces also called Plates.
The plates (pieces) are moving. The plates’ movement is
driven by cooling of Earth (convection).
?
?
?
Modified from USGS Graphics
Convection is like a boiling pot. Heated soup rises to the surface, spreads and
begins to cool, and then sinks back to the bottom of the pot where it is reheated
and rises again.
6 - Plate Tectonics
• Greek – “tektonikos” of a builder
• Pieces of the lithosphere that move
around
• Each plate has a name
• Fit together like jigsaw puzzles
• Float on top of mantle similar to ice cubes
in a bowl of water
7 - What are the two types of tectonic
plates?
1)Lithosphere
2) Asthenosphere
8 - What is the Lithosphere?
Lithospheric plate
• The 100-km-thick surface of the Earth;
• Contains crust and part of the upper mantle;
• It is rigid and brittle;
• Fractures to produce earthquakes.
USGS Graphics
9 - What is the asthenosphere?
Asthenosphere:
• Is the hotter upper mantle below the lithospheric
plate;
• Can flow like silly putty; and
• It is an elastic solid, NOT liquid!!
10 - Different Types of Boundaries
1) Transform (2) Divergent (3) Convergent
11 - Three Basic Types of Plate Boundaries
Divergent
Using hands to show relative motion
Transform
Convergent
USGS Graphics
12 - Three Basic Types of Plate
Boundaries
Divergent
Transform
Convergent
USGS Graphics
13 - Divergent Boundary –
Arabian and African Plates
14 Divergent Boundary – Iceland
15 -Convergent Boundary – Indian and Eurasian Plates
16 - Transform Boundary – San Andreas Fault
17 - Tectonic Plates
There are a dozen large lithospheric plates (smaller plates
not shown). Some plates have continents; some don’t. All
are in motion.
18 - Earthquakes
There are thousands of small earthquakes
every day. “Strong” earthquakes ( about
magnitude of 7) occur once a month. Magnitude
of over 8 occur about once/year.
19 - Earthquakes & Plate Boundaries
Notice that the earthquakes coincide with plate
boundaries, and the deepest quakes (blue) are in
subduction zones.
Modified from USGS Graphics
20 - Volcanoes & Plate Boundaries
Volcanoes also tend to occur along
the plate boundaries.
Modified from USGS Graphics
21 - How fast are the plates moving?
Plates move 1-10 centimeters per year
(about the rate of fingernail growth).
Review
• Name the 3 main layers of the Earth
• What is a tectonic plate?
• Name the three different types of plate
boundaries and one location on Earth for each
one
Review
• Name the 3 main layers of the Earth
– Crust, mantle, core
• What is a tectonic plate?
– Pieces of the lithosphere that move around
• Name the three different types of plate
boundaries and one location on Earth for each
one
– Divergent, Convergent & transform
What type of boundary is this?
What type of boundary is this?
What type of plate
boundary is this?