Mountain Building

Unit 4 Lesson 3 Mountain Building

How do mountains form?

By the end of this lesson, you should be able to describe how the movement of Earth's tectonic plates causes mountain building.

Multiple Choice

Mountains can originate from a level surface that is folded upwards.

• True

• False

Multiple Choice

Rocks can be pulled apart by the movement of tectonic plates.

• True

• False

Multiple Choice

All mountains are created by volcanoes.

• True

• False

Multiple Choice

A mountain range can form only at the edge of a tectonic plate.

• True

• False

-Shear stress

-Tension

-Compression

-Deformation

-Folding

-Fault

Unit 4 Lesson 3 Vocabulary

Multiple Choice

What is deformation?

(p. 218)

• Process when the rocks break apart or erode.

• Process of when rocks melt away. 

• Process when rocks change shape under pressure.

• Process when 

Open Ended

List 3 objects that can bend or break due to deformation?

Open Ended

How can some material bend in one situation but break in another?

(Hint: Think about the factors at work! - p.218)

Multiple Choice

Which theory states that the entire crust is broken and is continuously moving?

• Continental Drift

• Plate Tectonics

• Seafloor Spreading

• Titanic Theory

Explanation Slide...

Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium).

Multiple Choice

What do we call the continuously moving part of the earth’s crust?

• Fault

• Fissure

• Fracture

• Plate

Explanation Slide...

The theory of plate tectonics states that the Earth's solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle.

What is a fold?

• Folds are primarily caused by compressive stress.

• Folds form perpendicular to the direction of stress.

• Compression can form folds & faults.

Main Types of Folds

• Anticline and Synclines often form together as part of a series of folds.

• For Anticlines, (shaped like A)the oldest rock is in the center.

• Where Synclines have the youngest rock in the center of the fold.

Forces Changing Earth's Surface

Types of Forces

Compression - stress that squeezes or pushes rocks together

Shear - pushes rocks in parallel but opposite directions

Tension - stress that stretches or pulls rocks apart

Mountain ranges are produced by plate tectonics. Tectonic plate move slowly, only 1-9 cm per year. But these massive, slow moving plates have so much force they can build tall mountains!

Compression, tension, and shear cause rocks to

change shapes in different ways.

Multiple Choice

What type of fault is this?

• Normal

• Reverse

• Strike-slip

Multiple Choice

What type of fault is this?

• Normal

• Reverse

• Strike-slip

Multiple Choice

What type of fault is this?

• normal fault

• reverse fault

• strike-slip fault

Multiple Choice

Forces that changes rock shape or volume is called

• tension

• compression

• stress

Multiple Choice

Reverse faults have __________________ and folding that formed the Alps and Himalayas.

• tension

• compression

• stress

Multiple Choice

________________ pulls on crust which results in a normal fault.

• tension

• compressions

• stress

Multiple Choice

Which type of force is involved with this type of fault?

• Compression

• Tension

• Shear

Multiple Choice

Which type of fault is this (stress pushing in on both sides)?

• Normal

• Reverse

• Strike-Slip

Match

Match the following fault types with the type of stress that causes them.

• fault-slip

• normal

• reverse

shearing

tension

compression

• shearing

• tension

• compression

Fold mountains

Fold mountains are the most common type of mountain. The world’s largest mountain ranges are fold mountains.

Fold mountains

These ranges were formed over millions of years.

Fold mountains are formed when

two plates collide head on, and their edges crumbled, much the same way as a piece of paper folds when pushed together.

Multiple Choice

Fold mountains are formed when two plates collide head on and their edges are crumbled just like when you ball up a piece of paper.

• True

• False

Himalayas (Asia)

The Himalayan Mountains were formed when India crashed into Asia and pushed up the tallest mountain range on the continents.

Fault Block Mountains

These mountains form when faults or cracks in the earth's crust force some materials or blocks of rock up and others down.

Fault Block Mountains

Instead of the earth folding over, the Earth's crust fractures (pulls apart). It breaks up into blocks or chunks.

Sometimes these blocks of rock move up and down, as they move apart and blocks of rock end up being stacked on one another.

Sierra Nevada Mountains

Multiple Choice

Fault block mountains forms when the Earth's crust pulls apart and breaks off into chunks.

• True

• False

Form when melted rock erupts onto Earth's surface.

Can form on land or the ocean floor.

Most of Earth's active volcanoes are the edge of the Pacific Plate in the Pacific Ocean.

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​Volcanic Mountains