CALDERA / CRATERCALDERA / 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.

CRATERCRATER

CRATERCRATER

CALDERACALDERA

CALDERACALDERA

Intrusive Volcanic FeaturesIntrusive 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 Which intrusion is the sill and which is the dike?dike?

SillSill

The The neckneck of a volcano is the of a volcano is the solidified material that fills the vent solidified material that fills the vent or pipe of a or pipe of a deaddead volcano. volcano.

Devils Tower is a volcanic neck that is 865' tall. Devils Tower is a volcanic neck that is 865' tall. It is located in northeastern Wyoming. It was the first National Monument It is located in northeastern Wyoming. It was the first National Monument proclaimed in the United States.proclaimed in the United States.