1. 7.4 Volcanic landforms
Key concepts: What landforms to lava and ash create? How does magma that hardens beneath the surface create landforms? What other distinctive features occur in volcanic areas?
Key terms: shield volcano, cinder cone, composite volcano, caldera, volcanic neck, dike, sill, batholith, geothermal activity, geyser

2. Landforms from lava and ash
Volcanic eruptions create landforms made of lava, ash, and other materials. These landforms include:

3. Shield volcanoes
Shield volcano – when thin layers of lava pour out of a vent and harden on top of previous layers to build a wide, gently sloping mountain

4. Cinder cone volcano
Ash, cinders, and bombs build to form a steep, cone-shaped hill or small mountain called a cinder cone.

5. Composite volcano
Tall, cone-shaped mountains in which layers of lava alternate with layers of ash

6. Lava Plateaus
First, lava flows out of several long cracks in the area. It travels far out and cools. After millions of years, the layers can form high plateaus.

7. Calderas
Caldera – huge hole left by the collapse of a volcano.

8. Soils from lava and ash
Makes fertile soil because of potassium, phosphorus, etc

9. Landforms from magma
Features formed by magma include:

10. Volcanic necks
Forms when magma hardens in a volcano’s pipe

11. Dikes and sills and batholiths and dome mountains oh my
Dike – magma that forces itself across rock layers and hardens
Sill – magma squeezes between horizontal layers of rock
Batholith – mass of rock formed when a large body of magma cools inside the crust
Dome mountain - Forms when uplift pushes a batholith or a smaller body of magma to the surface

12. Geothermal activity Magma a few km below heats underground water
Hot springs and geysers are types of geothermal activity in areas of active volcanoes

13. Hot springs, geysers
Hot springs – groundwater is heated, hot water rises. May contain dissolved gases or minerals
Geysers – fountains of water and steam that erupt from the ground