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Chapter 16…what’s the connection?

Mountains and Plate Tectonics…

Mountain Building

Most crustal deformation occurs along plate margins.

Passive Margin

Active Margin

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Factors Affecting Deformation

Mountain Building

includes temperature, confining pressure, rock type, and time.

• Stress is the force per unit area acting on a solid.

• Strain is the change in shape or volume of a body of rock as a result of stress.

• Deformation - all changes in the original shape and/or size of a rock body.

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Types of Stress

Rock Deformation

The three types of stresses are:

tensional stress (pulling apart)compressional stress (pushing together)shearing stress (tearing apart)

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Types of Stress

tensional stress

compressional stress

shearing stress

Folds

Rock Deformation

Anticlines• Anticlines are most commonly formed by the

upfolding, or arching, of rock layers.Synclines

Monoclines• Monoclines are large step-like folds in

otherwise horizontal sedimentary strata.

• Synclines are linear downfolds in sedimentary strata.

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Anticlines and Synclines

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syncline anticline

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Monoclines

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monocline

Faults

Rock Deformation

Normal Faults• Normal faults occur when the hanging wall block

moves down relative to the footwall block.Reverse Faults and Thrust Faults• Reverse faults are faults in which the hanging

wall block moves up relative to the footwall block.• Thrust faults are reverse faults with dips less

than 45o.

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Faults

Rock Deformation

Joints• Joints are fractures along which no appreciable

movement has occurred.

Strike-Slip Fault• Strike-slip faults are faults in which the

movement is horizontal and parallel to the trend, or strike, of the fault surface.

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Four Types of Faults

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Joints

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Types of Mountains

Mountains are classified by the dominant processes that have formed them.

Orogenesis or Orogeny is the collection of processes that result in the forming of mountains.

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Types of Mountains

A. Fold & Thrust Mountains

B. Dome Mountains

C. Fault Block Mountains

D. Volcanic Mountains

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(see Chapter 14 notes)

A. Folded Mountains

Types of Mountains

Mountains that are formed primarily by folding are called folded mountains.

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Folded Mountains

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B. Domes and Basins

Types of Mountains

When upwarping produces a circular or elongated structure, the feature is called a dome.• Uplifted mountains are circular or

elongated structures formed by uplifting of the underlying basement rock.

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Domed Mountains

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C. Fault-Block Mountains

Types of Mountains

Large-scale normal faults are associated with structures called fault-block mountains.

• Fault-block mountains are formed as large blocks of crust are uplifted and tilted along normal faults.

• Grabens are formed by the downward displacement of fault-bounded blocks.

• Horsts are elongated, uplifted blocks of crust bounded by faults.

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Fault-Block Mountains

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Fault-Block Mountains

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D. Volcanic Mountains

Types of Mountains

Mountains that are formed primarily by eruptions and lava flows. See Chapter 14 notes for details.

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Mountain Building at Convergent Boundaries

Mountain Formation

Most mountain building occurs at convergent plate boundaries.Colliding plates provide the compressional forces that fold, fault, and metamorphose the thick layers of sediments deposited at the edges of landmasses.

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Mountain Building at ConvergentBoundaries

Mountain Formation

Ocean-Ocean Convergence• mainly produces volcanic mountains.

Ocean-Continent Convergence• volcanic mountains and folded mountains.

Continent-Continent Convergence• forms folded mountains.

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Ocean-Ocean Convergence

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Ocean-Continent Convergence

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Continent-Continent Convergence

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Mountain Building at DivergentBoundaries

Mountain Formation

The mountains that form along ocean ridges at divergent plate boundaries are fault-block mountains.

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Continental Accretion

Mountain Formation

Terranes• Terranes are any crustal fragments that

have a geologic history distinct from that of the adjoining fragments.

Accretion is a process that occurs when crustal fragments collide with and stay connected to a continental plate.

• Terranes occur along the Pacific Coast.

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Continental Accretion

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Accretion in Western North America

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Exercise 7

Folds and Faults!Complete Worksheet.

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Plate Tectonics Summary

Complete the following slides.(You have 5 minutes!)

Plate Tectonics Summary (1)

• The Earth is made up of 3 main layers (core, mantle, crust)

• Tectonic plates move slowly around the globe

• Plates are made of crust and upper mantle (lithosphere)

• Convection in the mantle (asthenosphere) moves the plates

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Plate Tectonics Summary (2)

• There are 2 types of plates (continental & oceanic)

• There are 3 types of plate boundaries (converging or subduction, diverging, sliding or transform)

• Volcanoes, Earthquakes and Mountain Building are closely linked to the margins of the tectonic plates

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Plate Tectonics Summary (3)

• There are 3 main types of volcanoes (shield, cinder, composite or stratovolcano)

• Volcanic activity includes rift eruptions, calderas, formation of plutons

• There are 2 main types of lava (felsic & mafic)

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Plate Tectonics Summary (4)

• There are 2 main types of seismic waves (surface & body)

• There are 2 main types of body waves (P & S)

• There are 4 main types of mountains(folded, fault block, dome and volcanic)

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UNIT TEST - Chapters 13-16

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Assignments:Chapter 13 – Plate Tectonics Notes & Vocab √Chapter 14 – Plate Tectonics & Volcanoes Notes & Vocab √Chapter 15 – Plate Tectonics & Earthquakes Notes & Vocab √Chapter 16 – Plate Tectonics & Mountain Building Notes & Vocab √

For Review and Test Prep:Go to esc11.weebly.com

• Flashcard Library (home page)• volcano photo review• link to practice quizzes and review PowerPoints• Quizlab – Chapters 13-16 Practice Test