1. Ch 10 Volcanoes
Volcano- vent in the Earth’s surface that often forms a mountain when layers of lava & volcanic ash erupt & build up

2. 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

3. B. Vent – opening in Earth’s surface that molten rock comes out of
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

4. D. Hot Spots
Areas where magma from deep in Earth’s mantle has melted through the crust to form several volcanoes

6. 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

7. Produces a large opening Ex. Crater Lake in Oregon
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

8. igneous rock (intrusion) that cools inside other rock
VI . Plutons
igneous rock (intrusion) that cools inside other rock

9. Types of Plutons
Dikes – vertical intrusion that cuts across layers, rock types do not match
Batholiths – largest igneous intrusions, forms when magma cools underground before reaching the surface

10. 3. Sills – form when magma squeezes into horizontal cracks & hardens
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

11. 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

12. Mt. Vesuvius, Pompeii, Italy 79 AD

13. Mt. Vesuvius, Pompeii, Italy 79 AD