What is orogenesis?
What is isostacy?
a difference in density
What is isostatic adjustment?
the process of finding a new equilibrium in elevation
What are three things that provide a need for isostatic adjustment?
Adding weight (like ice), removed weight (causes rebound up), and erosion
What is rock deformation caused by?
forces greater than the strength of the rocks
What are the types of rock deformation?
elastic deformation, plastic deformation, stress, strain, strike, dip
What is a reversable type of rock deformation?
When rocks first stretch up to the "elastic limit" like a rubber band, it is called
When rocks stretch past their elastic limit, then ____. This is called ____
permanent changes (flowing and folding) occur, plastic deformation
force per unit area
What is strain?
change in shape or size in response to stress
What are the 3 types of stress?
compressional, tensional, and shear
Compressive stress results in rocks being
Tensional stress results in rocks being
Shear stress results in rocks being
pulled parallel to a plane in opposite directions
What is a strike?
compass direction of line formed by intersection of horizontal and dipping planes
What is a dip?
What is an anticline?
a fold with the oldest rocks in the middle
What is a syncline?
a fold with the youngest rocks in the middle
What is a dome?
a round anticline that is pusing up
What is a basin?
a round syncline that is plunging down
What force causes a horst and grabben structure?
A horst is an
uplifted block of rock
A grabben is
a down dropped block of rock
fractures with no appreciable displacement
What causes joints?
shrinkage cracks from cooling igneous rock and unloading cracks from rising rock after weight has been removed