ASBOG Structural Geology and Tectonics 2

Question 1

Which type of fold has its oldest rocks in the core?

Accepted Answer

Anticline

Answer

Anticlines arch upward with the oldest rocks exposed at their core due to erosion.

Question 2

A thrust fault is characterized by which dip angle range?

Accepted Answer

Less than 45°

Answer

Thrust faults dip at less than 45° and involve the hanging wall moving up relative to the footwall under compressional stress.

Question 3

The Wilson Cycle describes the repeated opening and closing of which geological feature?

Accepted Answer

Ocean basins

Answer

The Wilson Cycle describes the cyclical opening and closing of ocean basins driven by plate tectonics.

Question 4

What is the term for the angle between a fault plane and the horizontal?

Accepted Answer

Dip

Answer

Dip is the angle measured downward from horizontal to the fault or bedding plane.

Question 5

Boudinage structures form when a competent layer is subjected to what type of stress?

Accepted Answer

Extension parallel to layering

Answer

Boudinage forms when a rigid layer is stretched and necked into sausage-shaped segments under extensional stress parallel to layering.

ASBOG - Association of State Boards of Geology Practice Test