CALDERA / CRATER
CRATER – FUNNEL SHAPED PIT AT THE TOP
OF A VOLCANO. FORMED WHEN MATERIAL
IS BLOWN OUT OF THE VOLCANO BY
EXPLOSIONS
CALDERA – WHEN THE VOLCANO
COLLAPSES DUE TO AN EMPTY MAGMA
CHAMBER.
CRATER
CRATER
CALDERA
CALDERA
Intrusive Volcanic Features
•Sills are thin horizontal sheets of hardened magma between layers.
•Laccoliths are blister-like intrusions, usually near the surface, that form when
magma pushes overlying layers upward.
•Dikes are thin vertical sheets of hardened magma intruded into fractures in the
crust.
•Batholiths are usually granitic and cover hundreds or thousands of square
kilometers.
Which intrusion is the sill and which is the dike?
Sill

The neck of a volcano is the solidified
material that fills the vent or pipe of a
dead volcano.
Devils Tower is a volcanic neck that is 865' tall.
It is located in northeastern Wyoming. It was the first National Monument
proclaimed in the United States.