Rock Deformation and Faulting

Question 1

Orogeny

Answer 1

A process in which a section of the earth’s crust is folded and deformed by lateral compression to form a mountain range.

Question 2

Stress

Answer 2

Tensional - Pull-apart (greater stress in one direction)
Compressional - Squeezing (greater stress in one direction)
Shear - Blocks of rock sliding past one another

Question 3

*Deformation

Answer 3

Elastic - strain that is reversible after a stress is released
Plastic - takes place when a rock, mineral, or other substance is stressed beyond its elastic limit
Brittle - irreversible strain when rocks break in pieces in response to stress

Question 4

*Strike & Dip

Answer 4

Strike-Slip – Blocks move parallel to fault-plane strike
Dip-Slip – Blocks move parallel to fault-plane dip

Question 5

*Anticline

Answer 5

Hinge points upward

Question 6

*Syncline

Answer 6

Hinge points downward

Question 7

Basin

Answer 7

Fold shaped like a bowl

Question 8

Dome

Answer 8

Fold with an appearance of an overturned bowl

Question 9

Isostasy / Isostatic Equilibrium

Answer 9

The state of gravitational equilibrium between Earth’s crust (or lithosphere) and mantle such that the crust “floats” at an elevation that depends on its thickness and density.

Question 10

*Faults

Answer 10

Normal fault - Hanging wall moves down
Reverse Fault - Hanging wall moves up
Thrust fault - a special type of reverse fault, with dip ≤ 45°

Question 11

*Hanging Wall

Answer 11

Block (above the fault)

Question 12

*Foot wall

Answer 12

Block (below the fault)

Question 13

Uplift

Answer 13

An increase in the vertical elevation of Earth’s surface in response to natural causes.