3.2 Results of Stress Photos

The Results of Stress...

1 Mr. Silva

Thursday, December 4, 2014

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


http://upload.wikimedia.org/wikipedia/commons/3/32/Anticline.jpg






































Anticline

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3 General Types of Folds• Syncline: is a linear downfold in which the youngest layer

is in the center

Youngest layer of rock


Syncline

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3 General Types of Folds• Monocline: is a step-like fold in which both limbs remain

horizontal or vertical.

Different layers remaining vertical


http://en.wikipedia.org/wiki/Image:Folded_Rock.jpg












































Monocline

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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


http://upload.wikimedia.org/wikipedia/en/0/0e/Fault_types.png



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: Convergent Plate Boundaries build 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 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


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


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Anticline, Syncline, Monocline


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Rock deformed by breaking...Brittle


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Rock deformed by breaking...Brittle

Normal, Reverse, thrust, and Strike-Slip


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


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Transform Fault Boundaries


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Transform Fault Boundaries

Continental-Continental Convergent Plate Boundaries


Education

3.2 Results of Stress Photos