Exam 9: Crustal Deformation

________ are planar extensional structures which thin the crust in response to horizontally directed, tensional stresses.

Name an economic resource associated with geologic structures.

Rocks that display contorted folds and other evidence of ductile flow usually were deformed at great depth.

The two sides of a fold are called its lobes.

A(n)________ has the strata on both limbs dipping away (outward from)the axis.

What are hogbacks?

Igneous and metamorphic rocks exposed in the "stable" interiors of continents have necessarily been uplifted from much deeper levels in the Earth's crust.

What is the cause of most earthquakes?

Most faults are inactive and stand as geologic evidence of past structural deformation.

What is a fault?

Normal faults form in response to horizontal, tensional stresses that stretch or elongate the rocks.

Horizontal, compressive deformation involves shortening and thickening of the crust.

Describe the most common way for a monocline to form.

Are horsts and grabens bounded by normal or reverse faults?

In a thrust fault, the hanging wall moves ________ relative to the footwall and the fault plane is oriented at a ________ angle.

A horst is ________.

A syncline is ________.

A graben is characterized by ________.

Which one of the following statements regarding rock deformation and strength is correct?

When measuring the orientation of a planar structure in rocks the dip direction is measured ________ to the strike.