Download Ch 14 Volcanoes - Toms River Regional Schools

Ch 10 Volcanoes
A.
Volcano- vent in the Earth’s surface
that often forms a mountain when layers
of lava & volcanic ash erupt & build up
What causes a Volcano?
 Heat & pressure cause rock to melt deep
within the Earth
 magma is formed
 magma is less dense than rock around it &
rises
Parts of a Volcano
B. Vent – opening in Earth’s surface that
molten rock comes out of
C. Crater – steep walled depression
around a volcano’s vent
http://www.brainpop.com/science/earth/volcanoes/index.weml
D. Hot Spots
• Areas where
magma from
deep in Earth’s
mantle has
melted through
the crust to
form several
volcanoes
Ex. The Hawaiian Island chain
• the Pacific Plate is moving over a stationary
hot spot
• Kauai is the oldest
• Lo’ihi an underwater
volcano will form the next
island in the chain
E. Caldera
• Formed when the top of a volcano
collapses into the partially emptied
magma chamber
• Produces a large opening
• Ex. Crater Lake in Oregon
VI . Plutons
• igneous rock (intrusion) that cools inside
other rock
Types of Plutons
1. Dikes – vertical intrusion that cuts across
layers, rock types do not match
2. Batholiths – largest igneous intrusions,
forms when magma cools underground
before reaching the surface
Types of Plutons
3. Sills – form when magma squeezes
into horizontal cracks & hardens
4. Laccolith – domed sill, that has pushed
up the rock above it
Stone Mt., Georgia
Types of Plutons
5. Volcanic neck – the hard solid vent of a
volcano left behind after the cone erodes
Ex. Ship Rock New Mexico & Devil’s Tower
Mt. Vesuvius,
Pompeii, Italy 79 AD
Mt. Vesuvius,
Pompeii, Italy 79 AD