VOLCANOES

YEAR 7

4. VOLCANIC LANDFORMS

1. Landforms from Lava and Ash:– Shield volcanoes (from hot spots)– Cinder cone volcanoes– Composite volcanoes – Lava plateaus (instead mountain)– Caldera (huge hole left after collapsing a

volcanic mountain)– Soils from lava and ash (good for plants)

SHIELD VOLCANO

CINDER CONE VOLCANO

COMPOSITE VOLCANO

LAVA PLATEAUS

CALDERA

2. Landforms from Magma:– Volcanic necks (giant tooth stick in the

ground). It forms when magma hardens in a volcano’s pipe.

– Dike (magma that forces itself across rock layers hardens into this structure)

– Sill (when magma squeezes between horizontal layers of rock)

–Batholiths (mass of rock formed when a large body of magma cools inside the crust)–Dome Mountains (other smaller bodies of

hardened magma can create dome mountains)

3. Geothermal Activity:– Hot spring forms when groundwater heated by a

nearby body of magma rises to the surface and collects in a natural pool.

– Geyser is a fountain of water and steam that erupts from the ground (when rising hot water and steam become trapped underground in a narrow crack)

5. VOLCANOES IN THE SOLAR SYSTEM

• Earth is not the only body in the solar system to show signs of volcanic activity.

• Pictures taken by space probes show evidence of past volcanic activity on Mercury, Venus and Mars (rocky planets)

• On Mars there are large volcanoes and lava flows. The largest mountain in the solar system is the Olympus Mons volcano (25km height).