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The Results of Stress...

Mr. Silva

Objective

• Students will be able to identify and describe two types of rock deformation and explain the difference between them.

• Students will be able to demonstrate three types of faults by acting them out using their backpack.

The Results of Stress

• High pressure and temperatures caused by stress in the crust generally deform rocks.

• When stress is applied slowly, the deformed rock will return to its original shape.

• In extreme stress, rock becomes so deformed it may bend, tilt or break.

Folding

• When rocks respond to stress by becoming permanently deformed without breaking it is called folding. –Folds vary in size–There are 3 general types of folds.

3 General Types of Folds

• Anticline:

Upfolding or arching in which the oldest layer is in the center of the of the fold

Oldest layer of rock

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Anticline

3 General Types of Folds

• Syncline:

is a linear downfold in which the youngest layer is in the center

Youngest layer of rock

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Syncline

3 General Types of Folds

• Monocline:

is a step-like fold in which both limbs remain horizontal or vertical.

Different layers remaining vertical

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Monocline

Faulting • When rocks break due to stress instead of

fold.– Joint: no movement in the rocks along either

side of a break. – Fault: when rocks do move– Fault plane: surface of a fault where any motion

occurs– Hanging wall: rock above the fault plane of a

nonvertical fault– Footwall: rock below the fault plane of a

nonvertical fault

3 Types of faults• Normal fault: hanging wall moves down

relative to the footwall along divergent boundary

• Reverse fault: compression causes the hanging wall to move up relative to the footwall

• Thrust fault: fault plane is a low angle or nearly horizontal & hanging wall is pushed up over rock

• Strike-slip fault: rock on either side of the fault plane slides horizontally at transform boundaries

Mountain Formation

• Mountain Range: a group of adjacent mountains with the same general shape and structure.

Mount Everest

Himalaya Mountains

Mountain Formation

• Mountain System: a group of adjacent mountain ranges.

Great Smoky Mountains

Green Mountains

Appalachian Mountains

Mountain Formation

• Mountain Belts: the largest mountain system are part of two still larger systems.

Eurasian- Melanesian

mountain belt

Circum-Pacific mountain belt

Plate Tectonics and Mountains

• Both circum-Pacific mountain belt and the Eurasian- Melanesian mountain belt are located along convergent plate boundaries.

• Evidence that most mountains are formed from plate collisions.

• Ding Ding: Ding Ding: Convergent Plate Convergent Plate Boundaries build Boundaries build mountains!!!mountains!!!

Collision between Continental and Oceanic Crust

• What do we know happens when continental and oceanic crust collide?

• What do we know happens when crust overlap each other? What can happen?

• This will cause large scale deformation.

Continental Continental Volcanic Arcs!!!Volcanic Arcs!!!

Collision between Continental and Oceanic Crust

Collision between Oceanic and Oceanic Crust

• One plate usually submerges below the other and will cause a volcanic island arc.

Mariana Island in the North Pacific Ocean

Collision between Oceanic and Oceanic Crust

Collisions Between Continents

• Mountains can also form when two continents collide.

Collisions Between Continents

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Review

• What is folding? What type of deformation?

• Name three folds...

• What is faulting? What type of deformation?

• Name four faults...

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Rock deformed without breaking...Ductile

Anticline, Syncline, Monocline

Rock deformed by breaking...Brittle

Normal, Reverse, thrust, and Strike-Slip

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Review

• What boundary are most mountains formed?

• What boundary do strike-slip faults occur?

• What convergent plate boundary are the tallest mountains formed?

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Convergent Plate Boundaries

Transform Fault Boundaries

Continental-Continental Convergent Plate Boundaries