Download Plate Tectonics PowerPoint

DO NOW Friday November 18th
1. What causes movement of the crustal
plates?
2. Which layer of the Earth is most
dense? Least dense? Explain how
you know.
TODAY’S PLAN
•I can list the layers of the Earth.
•I can describe the composition of the layers of the Earth.
•I can explain what causes movement of the crustal plates.
•I can relate density to the order of Earth’s layers.
TODAYS DO
•Kahoot Review
•Earth’s layers quiz
•Data Notebooks
•Discussion of Plate boundaries and movement
Quiz Expectations
• Please be quiet at all times.
• Do your best. (Eyes on own paper.)
• Finished?
– Turn your paper in to the front table
– Get out your data notebook, graph your last test
grade and your over all class average (from your
progress report).
– Write a goal for your next test grade and How you
are going to reach that goal.
– Raise your hand and leave your folder open so I
can check it.
DO NOW Tuesday November 22nd
• Sign out a ChromeBook.
• Go to my 8th Grade Science Page.
• Click on the first folder under Files/Links called
Plate Tectonics WebQuest
• Finish your Plate Tectonics WebQuest and turn
in to black basket.
• Pick up Plate Tectonics Gizmo WS from table.
• Click on Gizmos Website on my 8th grade
page.
• Login and complete Plate Tectonics Gizmo
DO NOW Monday November 28th
1. What is plate tectonics? Explain using
what you have learned so far.
TODAY’S PLAN
•I can define plate tectonics.
•I can identify types of plate boundaries.
•I can explain the movement of plates at the different
types of boundaries
•I can relate movement of plates to features/events
that occur at the plate boundaries.
TODAYS DO
•Hand out iLearn@Home assignments
•Complete graphic organizer about plate boundaries
• https://www.youtube.com/watch?v=0m
WQs1_L3fA
The Structure of the Earth and
Plate Tectonics
Structure of the Earth
Mantle
• The Earth is
made up of 4
main layers:
– Crust
– Mantle
– Outer Core
– Inner Core
Outer core
Inner core
Crust
The Crust
• This is where we live!
• The Earth’s crust is made
of:
Continental Crust
Oceanic Crust
- thick (10-70km)
- buoyant (less dense
than oceanic crust)
- mostly old
- thin (~7 km)
- dense (sinks under
continental crust)
- young
What is Plate Tectonics?
• If you look at a map of the world, you may notice that some of the
continents could fit together like pieces of a puzzle.
Plate Tectonics
• The Earth’s crust is divided into 12 major
plates which are moved in various directions.
• This plate motion causes them to collide, pull
apart, or scrape against each other.
• Each type of interaction causes a
characteristic set of Earth structures or
“tectonic” features.
• The word, tectonic, refers to the deformation of
the crust as a consequence of plate
interaction.
World Plates
What are tectonic plates made of?
• Plates are
made of rigid
lithosphere.
The lithosphere is
made up of the
crust and the upper
part of the mantle.
What lies beneath the tectonic plates?
• Below the
lithosphere
(which makes
up the tectonic
plates) is the
asthenosphere.
Plate Movement
• “Plates” of lithosphere are moved around by
the underlying hot convection cells in the
astenosphere.
DO NOW Tuesday November 19th
1. What type of boundary results in the
formation of mountains?
2. What type of boundary results in the
formation of deep ocean trenches and
volcanoes?
3. What type of boundary results in the
formation of the mid ocean and sea floor
spreading?
4. What type of boundary results in the
formation of a fault ilne and earthquakes?
TODAY’S PLAN
•I can define plate tectonics.
•I can identify types of plate boundaries.
•I can explain the movement of plates at the different
types of boundaries
•I can relate movement of plates to features/events
that occur at the plate boundaries.
TODAYS DO
•Finish/review discussion of Plate Boundaries
•Oreo Plate Tectonics
•Kahoot review of plate boundaries
Three types of plate boundary
• Divergent
• Convergent
• Transform
Divergent Boundaries
• Plates spreading apart (“Rifting”)
– As plates move apart new material is erupted to fill
the gap
– (2 ocean plates) Results in sea floor spreading
and forms the mid ocean ridge.
– (2 continental plates) Results in volcanoes
Sea-Floor Spreading
• Where two ocean plates are diverging
(moving apart), molten magma erupts,
forming underwater mountains under the
ocean called the mid-ocean ridge.
• As the oceans plates move further and
further apart, new ocean floor is
continuously added. This is called seafloor spreading.
Red = youngest crust
Age of Oceanic Crust
Courtesy of www.ngdc.noaa.gov
Convergent Boundaries
• Plates colliding together
• May form mountains, trenches, and/or
volcanoes
Convergent Boundaries
• There are three styles of convergent
plate boundaries
– Continent-continent collision
– Continent-oceanic crust collision
– Ocean-ocean collision
Continent-Continent Collision
• Forms mountains, e.g. European Alps, Himalayas
Continent-Oceanic Crust Collision
• Called SUBDUCTION
• Forms volcanoes and deep ocean
trenches
Subduction
• Oceanic lithosphere
subducts underneath the
continental lithosphere
• Oceanic lithosphere heats
and melts forming magma
• The magma rises forming
volcanoes
• E.g. The Andes
Ocean-Ocean Plate Collision
• When two oceanic plates collide, one runs over
the other which causes it to sink into the mantle
forming a subduction zone.
• The subducting plate is bent downward to form
a very deep depression in the ocean floor called
a deep ocean trench.
• The worlds deepest parts of the ocean are
found along trenches.
– E.g. The Mariana Trench is 11 km deep!
• Volcanoes are also formed resulting in
the formation of islands.
Transform Boundaries
• Where plates slide past each other
• Earthquakes frequently occur
Above: View of the San Andreas
transform fault
Real World Examples
• Divergent Plate Boundary
• Convergent Plate Boundary
• Transform Plate Boundary
Iceland: An example of continental rifting
• Iceland has a divergent
plate boundary running
through its middle= many
volcanoes
Himalayas: continent-continent
convergent boundary
Volcanoes and Plate
Tectonics…
…what’s the connection?
Pacific Ring of Fire
Volcanoes
form all
along the
oceanocean
convergent
plate
boundaries
(subduction
zones).
Ocean-Continent Convergence
The Andes
Mountains/
volcanoes
Transform Plate Boundary
The San Andreas Fault
California, USA
Volcanoes are formed by:
- Subduction (Continental-Ocean and
Ocena-Ocean Plate Convergence)
- Rifting (Divergent Plates)
- Hotspots
Earthquakes and Plate
Tectonics…
…what’s the connection?
• As with volcanoes, earthquakes are not
randomly distributed over the globe
Figure showing
the distribution of
earthquakes
around the globe
• At the boundaries between plates, friction
causes them to stick together. When built up
energy causes them to break, earthquakes
occur.
Plate Tectonics Summary
• The Earth is made up of 4 main layers (inner and
outer core, mantle, and crust)
• On the surface of the Earth are tectonic plates that
slowly move around the globe
• Plates are made of crust and upper mantle
(lithosphere)
• There are 2 types of plates (crust).
• There are 3 types of plate boundaries.
• Volcanoes and Earthquakes are closely linked to the
margins (or boundaries) of the tectonic plates.
Pacific Ring of Fire
Hotspot
volcanoes
What are Hotspot Volcanoes?
• Hot mantle plumes breaching the
surface in the middle of a tectonic plate
The Hawaiian island chain are
examples of hotspot volcanoes.
Photo: Tom Pfeiffer / www.volcanodiscovery.com
The tectonic plate moves over a fixed hotspot
forming a chain of volcanoes.
The volcanoes get younger from one end to the other.
Where do earthquakes form?
Figure showing the tectonic setting of earthquakes