Archive for January, 2011

Mountain Formation

What 3 type of plate colisions build mountains-

Collistion between continental and oceanic crust: As the oceanic crust was subducted pieces of crust called terranes were scraped off According to the microplate terrane theory, they became part of the continental crust.

Collision between oceanic crust and oceanic crust: As the oceanic plate subducts, water from the subducting lithosphere induces partial melting of mantle material to form magma.

Collision between continents: Mountains can also form when two coninents collide. the himalaya mountains were formed by just such a collision.

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January 31, 2011 at 8:23 pm Leave a comment

The Result of Stress

Compare folding and faulting as responses to stress: Folding is the bending of rock without breaking. Faulting is when the pressure has become so great that it breaks causing the fault.

Describe four types of faults:

Normal Fault:Hanging wall moves down relative to the footwall.

Reverse Fault:Fault in which the hanging wall moves up relative to the footwall.

Thrust Fault:A geological fault in which the upper side appears to have been pushed upward by compression

Strike-slip fault:a geological fault on which the movement is along the strike of the fault

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January 20, 2011 at 8:31 pm Leave a comment

How the Crust is Deformed

Predict isostatic adjustments that will result from changes in the thickness of the earth’s crust: The thicker the crust gets the more weight it has pushing down. The thinner the crust is the less weight is pushing down on the core.

Identify sources of stress in crustal rock:

Stress: is the amount of force per unit area that is placed on a given material.

Folding: Is the most easily observed where flat layers of rock are under compression and are squeezed inward from the sides.

Faulting:A defect or imperfection; flaw; failing: a fault in the brakes

January 10, 2011 at 8:29 pm Leave a comment