Plate Tectonics

CHAPTER

the BIG idea

The movement of tectonic plates causes geologic changes on Earth.

Earth has several layers.1.11.1

Continents change position over time.1.21.2

Plates move apart.1.31.3

Plates converge or scrape past each other.1.41.4

CHAPTER OUTLINE

VOCABULARY

KEY CONCEPT CHAPTER HOME

asthenosphere

Earth has several layers.1.1

SECTION OUTLINESECTION OUTLINE

mantle

outer core

inner core

lithosphere

crust

The lithosphere is made up of tectonic plates, which rest on the asthenosphere.

outer core

mantle

inner core

crust

lithosphere

asthenosphere

tectonic plate

VOCABULARY

KEY CONCEPT CHAPTER HOME

Continents change position over time.1.2

SECTIONOUTLINESECTIONOUTLINE

Gravity and motions in the asthenosphere move tectonic plates over Earth’s surface.

continental drift

Pangaea

mid-ocean ridge

convection

convection current

theory of plate tectonics

Earth’s tectonic plates. Arrows indicatethe direction of movement.

VOCABULARY

KEY CONCEPT CHAPTER HOME

Plates move apart.1.3

SECTIONOUTLINESECTIONOUTLINE

New crust is formed at divergent boundaries. Features include:• mid-ocean ridges

divergent boundary

convergent boundary

transform boundary

rift valley

magnetic reversal

hot spot

VOCABULARY

KEY CONCEPT CHAPTER HOME

Plates move apart.1.3

SECTIONOUTLINESECTIONOUTLINE

New crust is formed at divergent boundaries. Features include:• mid-ocean ridges• records of magnetic reversals

divergent boundary

convergent boundary

transform boundary

rift valley

magnetic reversal

hot spot

VOCABULARY

KEY CONCEPT CHAPTER HOME

Plates move apart.1.3

SECTIONOUTLINESECTIONOUTLINE

New crust is formed at divergent boundaries. Features include:• mid-ocean ridges• records of magnetic reversals• rift valleys

divergent boundary

convergent boundary

transform boundary

rift valley

magnetic reversal

hot spot

VOCABULARY

KEY CONCEPT CHAPTER HOME

oceanic-oceanic subduction

Plates converge or scrape past each other.

subduction

1.4

SECTIONOUTLINESECTIONOUTLINE

continental-continental collision

Crust is destroyed or folded at convergent boundaries. • Subduction boundaries form island arcs, deep-

ocean trenches, and coastal mountains. • Collision boundaries can form mountains.

oceanic-continental subduction

VOCABULARY

KEY CONCEPT CHAPTER HOME

oceanic-oceanic subduction

Plates converge or scrape past each other.

subduction

1.4

SECTIONOUTLINESECTIONOUTLINE

continental-continental collision

Crust is destroyed or folded at convergent boundaries. • Subduction boundaries form island arcs, deep-

ocean trenches, and coastal mountains. • Collision boundaries can form mountains.

oceanic-continental subduction

Crust is neither formed nor destroyed at transform boundaries.

VOCABULARY

KEY CONCEPT CHAPTER HOME

I. Earth has several layers.

A. Earth is made up of materials with different

densities.

1.1

1. Core, Mantle, Crust

C. The lithosphere is made up of many plates.

Earth has several layers.

B. Earth’s layers have different properties.

outer core

mantle

inner core

crust

lithosphere

asthenosphere

tectonic plate

KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY

VOCABULARY

KEY CONCEPT CHAPTER HOME

1. Evidence from the Sea Floor

B. The theory of plate tectonics explains how

plates and their continents move.

II. Continents change position over time.

1.2

A. Continents join together and split apart.

2. Causes of Plate Movement

1. Evidence for Continental Drift

Continents change position over time.

2. Pangaea and Continental Drift

3. Putting the Theory Together

continental drift

Pangaea

mid-ocean ridge

convection

convection current

theory of plate tectonics

KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY

VOCABULARY

KEY CONCEPT CHAPTER HOME

III. Plates move apart.

A. Tectonic plates have different boundaries.

B. The sea floor spreads apart at divergent

boundaries.

1.3 Plates move apart.

C. Continents split apart at divergent boundaries.

1. Mid-Ocean Ridges and Rift Valleys

2. Sea-Floor Rock and Magnetic Reversals

D. Hot spots can be used to track plate

movements.

divergent boundary

convergent boundary

transform boundary

rift valley

magnetic reversal

hot spot

KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY

VOCABULARY

KEY CONCEPT CHAPTER HOME

IV. Plates converge or scrape past each other.

A. Tectonic plates push together at convergent

boundaries.

B. Tectonic plates scrape past each other at

transform boundaries.

1.4 Plates converge or scrape past each other.

C. The theory of plate tectonics helps geologists

today.

3. Oceanic-Continental Subduction

1. Continental-Continental Collision

2. Oceanic-Oceanic Subduction oceanic-oceanic subduction

subduction

continental-continental collision

oceanic-continental subduction

KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY