Chapter 11 - Crustal Deformation and Mountain Building

How do mountainous regions experience gravitational collapse?

Mountains that have risen to extreme heights experience ductile spreading at depth and normal faulting as well as subsidence in the upper, brittle portion of Earth's crust

Which of the following scenarios could result in the development of a compressional mountain belt?

two landmasses collide

Batholiths, such as those that make up the Sierra Nevada Mountains of California, form at great depth in the crust. How could they have been exposed at the surface?

uplift and erosion

A trough, or downward fold, called a(n) __________ is formed when a rock is deformed through folding.

SYNCLINE

hanging wall moves up relative to footwall

reverse fault

If a rock undergoes folding and is compressed to form an upward arch, this is a(n) _________ type fold.

ANTICLINE

hanging wall moves down relative to footwall

Caused by tensional forces Normal fault

If strike and dips symbols were placed on a map of a basin, which way would the dips point?

Dips point down toward the center.

What is a fault?

FRACTURES along which rocks MOVE

_____ is the principle that explains why materials uplift to a certain elevation.

Isostasy

When a rock is under undue stress and fractures but there is no movement to either side of the fracture, the feature is a called a ________. If, however, there is movement, it is called a ___________

JOINT, FAULT

Large rifts or valleys, which can often have very large __________ faults, are created by tensional forces.

NORMAL

Which of the following statements best describes the orientation of rock layers for a structural dome or structural basin?

Rock layers wrap around a single point.

Why are terranes added to continental margins, rather than subducting under them?

Terranes are too buoyant to subduct.

Using what you know about isostasy, how would the crust behave if a large glacier were removed?

The crust would move up in elevation.

Which of the following statements about terranes is most accurate?

The margins of MANY continents have GROWN through the accretion of terranes.

If the Rocky Mountains were eroded, what would happen to the roots of the mountains?

The roots would rebound upward.

A terrane is __________.

a mass of rock that formed elsewhere and was added to a continent

What is a terrane?

a slice of lithosphere that has been added to the margin of a continent during plate collision

What is the name of the process by which terranes are added to continents?

accretion

Which type of force is responsible for reverse fault formation?

compressional force

Which tectonic boundary is associated with the addition of terranes to a continent?

convergent boundary

Compressional

folded rocks -><-

Where does most terrane accretion occur?

in association with a continental-oceanic subduction zone

Which geologic features would be present in compressional mountain belts? (Note: There may be more than one answer.)

intrusive igneous rocks folds thrust faults

Tensionl

normal fault <-->

Which of the following rocks are characteristic of compressional mountain building?

schist

Which type of force is responsible for normal strike-slip formation?

shear force

shear

strike slip rocks arrows are goint opposite directions

Which type of fault has NO vertical motion of rocks associated with it?

strike-slip fault

Which type of force is responsible for normal fault formation?

tensional force

What are rocks below and above a fault called?

the FOOTWALL below and the HANGING wall above