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Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming the Earth’s Crust Copyright © by Holt, Rinehart and Winston. All rights rese End of Slide

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Page 1: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Plate TectonicsModule F: Chapter 4

Section 1: Inside the Earth

Section 2: Restless Continents

Section 3: The Theory of Plate Tectonics

Section 4: Deforming the Earth’s Crust

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 2: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the EarthSection 1

Bell Ringer

Recall your knowledge of the rock cycle, and if you journeyed to the center of the Earth, what do you think you would see along the way? Draw an illustration of the journey in your notes.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 3: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the EarthSection 1

Objectives

• Identify the layers of the Earth by their composition.

• Identify the layers of the Earth by their physical properties.

• Describe a tectonic plate.

• Explain how scientists know about the structure of Earth’s interior.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Warning!!!!!!!

You must understand these objectives to master this section!!!!!!

Did you read the objectives?

Page 4: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the EarthSection 1

The Composition of the Earth• The Crust: The outermost layer of the Earth is the crust. The crust is 5 to 100 km thick. It is the thinnest layer of the Earth, and it is mainly made of silicate material, which consists of mostly the elements silicon and oxygen.

• The Mantle: The layer of the Earth between the crust and the core is the mantle. The mantle is much thicker than the crust and contains most of the Earth’s mass.

• The Core: The layer of the Earth that extends from below the mantle to the center of the Earth is the core. Scientists think that the Earth’s core is made mostly of iron.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 5: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Composition of the EarthSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Did you read the captions?

Page 6: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Physical Structure of the EarthSection 1

The Physical Structure of the Earth

• Five Physical Layers The Earth is divided into five physical layers— the lithosphere, asthenosphere, mesosphere, outer core, and inner core.

• Illustrated Earth The next slides will show these five layers.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 7: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Earth’s Crust, Lithosphere, & AsthenosphereSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Did you read the captions?

Which layer is made of tectonic plates?

End of Slide

Page 8: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Earth’s Mesosphere, Outer Core, and Inner CoreSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Did you read the captions?

The inner core is liquid: true or false?

Page 9: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the EarthSection 1

Tectonic Plates

• A Giant Jigsaw Puzzle: Each tectonic plate fits together with the tectonic plates that surround it. The lithosphere is like a jigsaw puzzle, and the tectonic plates are the pieces.

• A Tectonic Plate Close-up: Many tectonic plates not only consist of the upper part of the mantle but also consist of both oceanic crust and continental crust.

• Like Ice Cubes in a Bowl of Punch: Tectonic plates “float” on the asthenosphere. The plates cover the surface of the asthenosphere, and they touch one another and move around.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 10: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

A Tectonic PlateSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 11: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Tectonic PlatesSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Does the North American plate consist of oceanic crust, continental crust, or both?

Page 12: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Tectonic Plates & MovementSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

In which general direction is the North American plate moving?

Page 13: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the Earth & MappingSection 1

Mapping the Earth’s Interior

• Seismic Waves: When an earthquake happens, vibrations called seismic waves are produced. Seismic waves travel at different speeds depending on the density and composition of material that they pass through.

• Seismographs: When an earthquake happens, machines called seismographs measure the times at which different seismic waves arrive and record the differences in their speeds. Seismologists can then use these measurements to calculate the density and thickness of Earth’s layers.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 14: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the Earth & MappingSection 1

Mapping the Earth’s Interior

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

P or Primary Waves:• First to arrive & fastest• Travel through all states of matter• Faster through dense material• Compression waves: squeeze or push/pull like a slinkyS or Secondary Waves:•Second to arrive & slower• Travel only through solids• Shear waves: move up & down like a rope

Page 15: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the Earth & MappingSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

P waves can travel through gases.

S waves can travel through liquids.

P waves are called compression waves.

S waves cannot travel through the Earth’s core.

True or False

Seismographs record S waves first.

True

False

False

True

True

Page 16: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the Earth & MappingSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

How a seismograph works

• Click on the picture below to open website• Then click on animation “How a Seismograph Works”

Page 17: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Inside the Earth & MappingSection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

How Seismic Waves Move

Page 18: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Restless ContinentsSection 2

Bell Ringer

Judge what is meant by the following statement: “The United States is moving westward.” From what you know about geology and plate tectonics explain if you believe this statement to be true or false.  Record your answer in your notes.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 19: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Restless ContinentsSection 2

Objectives

• Describe Wegener’s hypothesis of continental drift.

• Explain how sea-floor spreading provides a way for continents to move.

• Describe how new oceanic lithosphere forms at mid-ocean ridges.

• Explain how magnetic reversals provide evidence for sea-floor spreading.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 20: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Restless ContinentsSection 2

Wegener’s Continental Drift Hypothesis

Copyright © by Holt, Rinehart and Winston. All rights reserved.

• What Is Continental Drift? Continental drift is the hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations.

The Breakup of Pangaea• Pangaea, a single huge continent, existed about 245 million years ago. Pangaea split into two large continents— Laurasia and Gondwana— about 180 million years ago. The next slide shows how Pangaea eventually broke up into the continents that exist today.

End of Slide

Page 21: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of PangaeaSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 22: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea AnimationSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Yes! There is a question hidden here! If you’re ready then click away!

What are the names of the two land masses that were created when Pangaea broke-up?

Click on the Earth to view Pangaea’s breakup & the future world!

End of Slide

Page 23: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea: EvidenceSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 24: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea & Fossil RecordSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

A scientist named Wegener observed that similar fossils existed on the different continents.

Page 25: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea & GeographySection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Wegener also observed that the continents fit together like a jigsaw puzzle, and terrain features like mountain ranges lined up. End of Slide

Page 26: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea & Sea Floor SpreadingSection 2

Sea-Floor Spreading

Copyright © by Holt, Rinehart and Winston. All rights reserved.

• Mid-Ocean Ridges and Sea-Floor Spreading: Mid-ocean ridges are places where sea-floor spreading takes place. Sea-floor spreading is the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies.

• Evidence for Sea-Floor Spreading: Magnetic Reversals When Earth’s magnetic poles change places, this change is called a magnetic reversal.

• Magnetic Reversals and Sea-Floor Spreading Magnetic reversals are recorded over time in oceanic crust.

End of Slide

Page 27: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Breakup of Pangaea & Sea Floor SpreadingSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Where does sea floor spreading take place?

Where is the youngest oceanic crust located?Near the mid-ocean ridge or away from it?

Are you smarter than a fifth grader? What type of rock is formed at mid-ocean ridges? The answer is not on the slide but in your head!

•Click on the picture to the right to open website•Then click on “(2.5) Sea Floor Spreading” to view animation

Page 28: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Sea-Floor Spreading & Magnetic ReversalsSection 2

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

•Click on the picture below to open website

•Then view two related animations

• Click on “(2.3) Magnetic Reversals”• Click on “(2.4) Wandering Poles or Continental Drift”

Page 29: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Theory of Plate TectonicsSection 3

Bell Ringer

If the sea floor is spreading an average of 4 cm a year, how many years did it take New York and the west coast of Africa to reach their current locations, 676,000,000 cm apart? Calculate your answer in your notes.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 30: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Theory of Plate TectonicsSection 3

Objectives

• Describe the three types of tectonic plate boundaries.

• Describe the three forces thought to move tectonic plates.

• Explain how scientists measure the rate at which tectonic plates move.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 31: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Theory of Plate TectonicsSection 3

Tectonic Plate Boundaries

• Convergent Boundaries: When two tectonic plates collide, the boundary between them is a convergent boundary.

• Divergent Boundaries: When two tectonic plates separate, the boundary between them is called a divergent boundary.

•Transform Boundaries: When two tectonic plates slide past each other horizontally, the boundary between them is a transform boundary.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 32: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Convergent BoundariesSection 3

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Did you read the captions?

End of Slide

Page 33: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Divergent & Transform BoundariesSection 3

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 34: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Tectonic Plate Boundaries: AnimationSection 3

Copyright © by Holt, Rinehart and Winston. All rights reserved.

1. Click on picture to right to open a webpage containing the animations2. Then go to Exploring Earth3. Then go to Visualizations4. Then go to Chapter 85. Then go to link with code: ES0804 End of Slide

To view animations for tectonic plate boundaries follow the instructions below:

Page 35: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Theory of Plate TectonicsSection 3

Possible Causes of Tectonic Plate Motion

• Movement of the Asthenosphere: The solid rock of the asthenosphere flows very slowly. This movement occurs because of changes in density within the asthenosphere. These density changes are caused by the outward flow of thermal energy from deep within the Earth. As you can see on the next slide, movements of the asthenosphere may lead to tectonic plate motion.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Okay! This is a mouthful! Imagine that the Asthenosphere is a big lava lamp. The heated globs float upward, cool, then sink where they are reheated, and the cycle starts all over again. Does this help?

Page 36: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Possible Causes of Tectonic Plate MotionSection 3

Copyright © by Holt, Rinehart and Winston. All rights reserved.

There are three possible causes:Ridge Push, Slab Pull, and Convection (the lava lamp theory)

Did you read the captions?Can you explain the three theories?

Please raise your hand to let your teacher know that you are ready to explain one of these theories? End of Slide

Convection

Page 37: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The Theory of Plate TectonicsSection 3

Tracking Tectonic Plate Motion

• Measuring Tectonic Plate Movement: Tectonic plate movements are so slow and gradual that you can’t see or feel them— the movement is measured in centimeters per year.

• The Global Positioning System: Scientists use a system of satellites called the global positioning system (GPS) to measure the rate of tectonic plate movement.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 38: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Objectives

• Describe two types of stress that deform rocks.

• Describe three major types of folds.

• Explain the differences between the three major types of faults.

• Identify the most common types of mountains.

• Explain the difference between uplift and subsidence.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 39: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Deformation

• What Is Deformation? The process by which the shape of a rock changes because of stress is called deformation.

• Compression and Tension The type of stress that occurs when an object is squeezed, such as when two tectonic plates collide, is called compression. Another form of stress is tension. Tension is stress that occurs when forces act to stretch an object.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 40: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Folding

• What Is Folding? The bending of rock layers because of stress in the Earth’s crust is called folding.

• Types of Folds The two most common types of folds— anticlines, or upward-arching folds, and synclines, down-ward, trough-like folds. Another type of fold is a monocline. In a monocline, rock layers are folded so that both ends of the fold are horizontal.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 41: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming & Folding Section 4

Folding

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

A: MonoclineB: AnticlineC: Syncline

Page 42: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming & Folding Section 4

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of SlideSyncline

End of Slide

Which type of fold?

Page 43: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming & Folding Section 4

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of SlideAnticline

Which type of fold?

Page 44: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming & Folding Section 4

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of SlideMonocline

Which type of fold?

Page 45: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Faulting• Normal Faults: When a normal fault moves, it causes the hanging wall to move down relative to the footwall.

• Reverse Faults When a reverse fault moves, it causes the hanging wall to move up relative to the footwall.

• Telling the Difference Between Faults You can what kind of fault a fault is by looking at the order of sedimentary rock layers on each side of the fault.

• Strike-Slip Faults Strike-slip faults form when opposing forces cause rock to break and move horizontally.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 46: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Faulting

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

1. Click on picture 2. Then go to Exploring Earth3. Then go to Visualizations4. Then go to Chapter 115. Then go to link with code: ES1103 & ES1105

Page 47: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Plate Tectonics and Mountain Building

• Folded Mountains: Folded mountains form when rock layers are squeezed together and pushed upward.

• Fault-Block Mountains: Fault-block mountains form when this tension causes large blocks of the Earth’s crust to drop down relative to other blocks.

• Volcanic Mountains: The rock that is melted in the subduction zone forms magma, which rises to the Earth’s surface and erupts to form volcanic mountains.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 48: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Plate Tectonics and Mountain Building

• Folded Mountains Folded mountains form when rock layers are squeezed together and pushed upward.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 49: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s Crust & Fault Block MtsSection 4

Plate Tectonics and Mountain Building

• Fault-Block Mountains Fault-block mountains form when this tension causes large blocks of the Earth’s crust to drop down relative to other blocks.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 50: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Plate Tectonics and Mountain Building

• Volcanic Mountains The rock that is melted in subduction zone forms magma, which rises to the Earth’s surface and erupts to form volcanic mountains.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 51: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

Deforming the Earth’s CrustSection 4

Uplift and Subsidence

• Uplifting of Depressed Rocks: Uplift often happens when a weight is removed from the crust.

• Subsidence of Cooler Rocks: Rocks that are hot take up more space than cooler rocks. The farther the lithosphere is from the ridge, the cooler and denser the lithosphere becomes. Because the oceanic lithosphere now takes up less volume, the ocean floor subsides.

• Tectonic Letdown: Subsidence can also occur when the lithosphere becomes stretched in rift zones.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

Page 52: Plate Tectonics Module F: Chapter 4 Section 1: Inside the Earth Section 2: Restless Continents Section 3: The Theory of Plate Tectonics Section 4: Deforming

The EndSection 4

Copyright © by Holt, Rinehart and Winston. All rights reserved.

End of Slide

If you are unsure of any concept in this Power Point presentation, please review animations in your online textbook (Visual Concepts). For further assistance, please complete the interactive tutorial in your online textbook (Activities and Quizzes)