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 it’s original shape.• In extreme stress, rock becomes so deformed it may 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: Upcurve fold in which the oldest layer is in the center of the of the fold ck la ye r of roOldest
3 General Types of Folds• Syncline: is a down curved fold in which the youngest layer is in the center You n ges t lay er o f ro ck
3 General Types of Folds• Monocline: is a fold in which both limbs remain horizontal or vertical. Di ffe ren tl ay er s re m ai ni ng ve rti ca l
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. Circum-Pacific mountain beltEurasian- Melanesian 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.
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 causelarge scale deformation.
Collision between Oceanic and Oceanic Crust• One plate usually submerges below the other and may cause a volcano. Mariana Island in the North Pacific Ocean
Collisions Between Continents• Mountains can also form when two continents collide.
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