FOLDS, FAULTS and DEFORMATION



Stress


Compressive     = > <=


Tension		   < >


Shear		   =>								      
	           <=


Strain

	
Elastic - Recoverable
	Brittle Behavior




Plastic - Non Recoverable
	Ductile Behavior



Orientation of Features



The INTERSECTION of two planes defines a 
straight line


	Let one plane be the surface of the Earth and 
	the other be an inclined geologic unit
	This is the STRIKE of the inclined unit

The DIP is the angle that the inclined unit 
makes with the surface



FOLDS	- Plastic Behavior



Compressive Stresses




"UP" folds are anticlines - beds dip away 
from each other



"DOWN" folds are synclines - beds dip 
toward each other



The AXIAL PLANE divides the fold into two 
equal halves



If the dips are the same the fold is 
symmetrical - otherwise asymmetrical