Chapter 10, Section 2
Standards
3b. Students know the principal structures that form at
the 3 different kinds of plate boundaries.
Chapter 10, Section 2
Objective 1 Summarize the theory of plate tectonics.
Objective 2 Identify and describe the 3 types of plate
boundaries.
Objective 3 List and describe 3 causes of plate
movement.
Assessment Flap Book, Chapter Test
Review
Daily Bellwork, Science Starters,
Standards Practice
Key Terms
Create a flashcard for each of the following terms
(found on p.247 in your text book).
Plate tectonics
Lithosphere
Asthenosphere
If you finish early, study your flashcards!
Plate Tectonics
• The theory of Continental Drift led to the theory of PLATE
TECTONICS.
• PLATE TECTONICS explains how large pieces of the lithosphere,
called plates, move and change shape.
• Earth’s crust and the rigid, upper part of the mantle =
LITHOSPHERE. This is the thin outer shell of Earth (like an Egg
shell).
• The lithosphere is broken into several pieces called TECTONIC
PLATES.
• The TECTONIC PLATES ride or float on the ATHENOSPHERE (part
of the Earth’s mantle that is flowing slowly).
Earth’s Crust
• OCEANIC CRUST = dense, made of
iron and magnesium-rich rock.
• CONTINENTAL CRUST = low density,
made of rock rich in silica.
• Both kinds of crust are always
moving with the tectonic plates they
are riding on.
Tectonic Plates
• 15 major tectonic plates.
Earthquakes and Volcanoes
• Frequent earthquakes in an area are
evidence the 2 or more tectonic plates
meet in that area.
• Many volcanoes form from plate motion
and help scientist identify plate
boundaries.
Quick Check!!
1. The upper and hard part of the Earth’s mantle is called the
______________________.
2. The two types of crust are continental and ____________.
3. Scientists have identified about ______ major tectonic plates.
4. Name one plate:
______________________________________________________
______________________________________________________
______________________________________________________
_______________
Types of Plate Boundaries
• Most of the dramatic changes in Earth’s
crust---Volcanoes and Earthquakes--occur at Plate Boundaries.
Divergent
Convergent
Transform
Divergent Boundaries
• 2 plates move away from each other.
• Magma from the athenosphere rises to
the surface as the 2 plates move apart,
the magma cools and creates new
oceanic lithosphere(sea-floor spreading).
Convergent Boundary
• 2 plates collide
• 3 types of Collisions
Types of Collisions
Oceanic Lithosphere vs. Continental
• Oceanic is denser so it sinks under the continental lithosphere
• Called a SUBDUCTION ZONE
• Deep-ocean trenches and Volcanoes form at SUBDUCTION ZONES
Continental vs. Continental Lithosphere
• Neither plate subducts
• Colliding edges crumple and thicken causing uplift that forms large
mountain ranges.
Oceanic vs. Oceanic Lithosphere
• One plate subducts under the other
• Deep ocean trench forms
• Magma rises to form and ISLAND ARC, or chain of Volcanic Islands
Transform Boundaries
• 2 plates slide past each other horizontally
• The edges of the plates scrape and jolt
along each other. This motion is felt as
Earthquakes.
• No Magma is produced
Summary—Plate Boundaries
Divergent
Plates moving away from each
other to form rifts and midocean ridges
Convergent Plates moving toward each
other and colliding to form
ocean trenches, mountain
ranges, volcanoes, and island
arcs
Transform
Plates sliding past each other
while moving in opposite
directions
North American and
Eurasian plates at the
Mid-Atlantic Ridge.
Red Sea.
South American and
Nazca plates at the
Chilean trench along
the west coast of
South America.
Himalyan mountains,
Japan.
North American and
Pacific Plates at the
San Andreas fault in
California.
Quick Check!!
1. Name the 3 types of plate boundaries:
____________________________________
____________________________________
____________________________________
2. San Andreas fault is an example of a
_________ boundary.
3. 2 plates moving apart is a _________
boundary.
4. Mid-Atlantic Ridge is causing South America
and _______ to spread apart.
Causes of Plate Motion
Ridge Push
Mantle Convection
1. Heat from the Earth’s core heats the material
in the Mantle.
2. The heated material expands and becomes less
dense therefore rising around the cooler,
denser material above it.
3. This cycle continues, this is called
CONVECTION.
4. Convection currents cause the tectonic plates
above it to move.
Plate Tectonics Video Clip
Assessment
Make a 3-Flap Book showing each of the
types of plate boundaries. For each
flap include:
--Definition/Description
--Drawing
--Real World Example
Daily Quiz