miss nelson science ~ chapter 6 volcanoes. volcanoes and plate tectonics section 1
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Miss Nelson
SCIENCE ~ CHAPTER 6
VOLCANOES
Volcanoes and Plate Tectonics
SECTION 1
What do you remember about plate tectonics?
What are the types of plate boundaries?
ANTICIPATORY SET
S 6.1–Plate tectonics accounts for important features of Earth’s surface and major geologic events.
S 6.1.e – Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions
STANDARDS
Where are most of Earth’s volcanoes found?
How do hot spot volcanoes form?
THE BIG IDEA
Volcano – a weak spot in the crust where magma has come to the surface
Magma – the molten mixture of rock-forming substances, gases, and water from the mantle
Lava – liquid magma that reaches the surface; also, the rock formed when liquid lava hardens
KEY TERMS
Ring of Fire – Volcano belt that rims the Pacific Ocean
Island arc – a string of islands formed by the volcanoes along a deep-ocean trench
Hot spot – an area where magma from deep within the mantle melts through the crust above it
KEY TERMS
Read “Volcanoes and Plate Tectonics” on page 216 of your
textbook
VOLCANOES AND PLATE TECTONICS
Volcanoes occur in belts that extend across continents and oceans
One major volcanic belt is the Ring of FireFormed by the many volcanoes that rim the Pacific Ocean
VOLCANOES AND PLATE BOUNDARIES
Volcanic belts form along the boundaries of Earth’s plates
VOLCANOES AND PLATE BOUNDARIES
At plate boundaries, huge pieces of crust spread apart or collide
As a result, the crust often fractures, allowing magma to reach the surface
Most volcanoes form along spreading boundaries such as mid-ocean ridges and along colliding boundaries where subduction takes place
VOLCANOES AND PLATE BOUNDARIES
Volcanoes form along the mid-ocean ridgesWhich mark spreading boundaries
Volcanoes also form along spreading boundaries on land
SPREADING BOUNDARIES
Many volcanoes form near colliding boundaries where oceanic plates return to the mantle
Volcanoes may form where two oceanic plates collide OR where an oceanic plate collides with a continental plate
View the diagram on page 218 of your textbook
COLLIDING BOUNDARIES
Many volcanoes occur near boundaries where two oceanic plates collide
The resulting volcanoes create a string of islands called an island arc
The curve of the island arc mirrors the curve of its deep-ocean trench
COLLIDING BOUNDARIES
Volcanoes also occur where an oceanic plate is subducted beneath a continental plate
COLLIDING BOUNDARIES
Read Volcanoes and Plate Boundaries on pages 217-218 of
your textbook
VOLCANOES AND PLATE BOUNDARIES
A volcano forms above a hot spot when magma erupts through the crust and reaches the surface
HOT SPOT VOLCANOES
Some hot spot volcanoes lie in the middle of plates far from any plate boundaries
Other hot spots occur on or near plate boundaries
HOT SPOT VOLCANOES
A hot spot in the ocean floor can gradually form a series of volcanic mountains
Hot spots can also form under the continents
HOT SPOT VOLCANOES
Where are most volcanoes located?
What is a hot spot?
CHECK FOR UNDERSTANDING
Where are most volcanoes located?Most volcanoes are located at colliding and spreading plate boundaries.
What is a hot spot?A hot spot is an area where material rises from deep within the mantle and melts to form magma.
CHECK FOR UNDERSTANDING
How does a hot spot volcano form?
GUIDED PRACTICE
How does a hot spot volcano form?A hot spot volcano forms as, over time, lava flows to the surface and forms new rock. The layers of rock accumulate to form a volcano.
GUIDED PRACTICE
Complete Volcanoes 6-1 Independent Practice
INDEPENDENT PRACTICE
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