Geology Chapter 15 Summary

the strike tells you which way the plane is tilted, and the dip angle tells you how steeply it is tilted. 

Stress = measure of tectonic force and confining pressure acting on bedrock

Compressive stress = pushed and squeezed in opposite dir.

Tensional Stress = forces pulling away from one another in opposite directions

shearing = stresses parallel to plane

strained = changes in shape or size in response to stress

Strike = tells you which way the plane is tilted

Angle of dip = measured downward from horizontal plane to bedding plane

Direction of dip = compass direction in which angle dip is measured

If rock layers bend (ductile) rather than break they become = folded

Elastic = deformed recover its original shape after stress reduced or removed

ductile = plastic manner bend under stress and not return to original shape after stress removed

Brittle = fracture at stress higher than elastic limit

Anticline = fold shaped like an arch

Syncline = counterpart of anticline shaped like a trough. youngest rock in center of fold

if hinge line of fold is not horizontal the fold is = Plunging

Older beds exposed in core of fold indicate = anticline

younger beds in center indicate = syncline

oldest rock in center = anticline

youngest rock = center of syncline

bed dip toward center = syncline

bed dip away from center = anticline

Joint indicates = movement has not occurred on either side of fracture

displaced rock along a fracture indicates a = fault

Joint = fractures fracture in rock without movement

Fault = fractures in bedrock which sliding has taken place

Dip-slip = movement up and down parallel to inclined surface

Normal fault = hanging wall block moved down

Reverse fault = hanging wall moved up

Hanging wall = side of fault above the inclined surface

Strike slip fault = movement predominately horizontal and parallel to strike of fault