VOLCANIC LANDFORMS

SHIELD VOLCANOES

• shield volcanoes created the Hawaiian Islands and the Medicine Lake volcano
• thin layers of lava pour out of a vent and harden on top of previous layers
• lava flows gradually build a wide, gently sloping mountain called a Shield Volcano

CINDER CONE

• paricutin in Mexico erupted in 1943 in a farmer's cornfield
• the volcano built up a cinder cone about 400 meterhigh
• ash, cinders and bombs build up around the vent in a steep, cone-shaped hill or small mountain called a Cinder Cone

COMPOSITE VOLCANOES

• composite volcanoes are tall, cone-shaped mountains
• layers of lava alternate with layers of ash
• Mount Fuji in Japan and Mount Shasta and Lassen Peak in California are composite volcanoes

LAVA PLATEAU

• some eruptions form high, level areas called a lava plateau
• lava flows out of several long cracks, or fissures, in an area
• after millions of years, these layers of lava can form a high plateau

CALDERA

• A huge hole left by the collapse of a volcanic mountain is called a caldera
• the hole is filled with the pieces of the volcano that have fallen inward, as well as some lava and ash
• Enourmous eruptions may empty the main vent and the magma chamber beneath a volcano

Soils from lava and ash

• When volcanic ash breaks down, it releases potassium, phosphorus, and other substances that plants need
• some volcanic soils are among the richest soils in the world
• people often settle close to volcanoes to take advantage of the fertile volcanic soil

landforms from magma

• sometimes magma forces its way through cracks in the upper crust, but fails to reach the surface
• there the magma cools and hardens into rock

volcanic necks

• a volcanic neck looks like a giant tooth stuck in the ground
• A volcanic neck forms when magma hardens in a volcano's pipe
• the softer rock around the pipe wears away, exposing the hard rock of the volcanic neck

Dikes anD Sills

• magma that forces itself across the rock layers hardens into a dike
• when magma squeezes between horizontal layers of rock, it forms a sill
• dikes and sills are examples of igneous intrusions, an intrusion forms when magma hardens underground to form igneous rock, An intrusion is always younger than the rocks around it

batholiths

• Large rock masses called batholiths form the core of many mountain ranges
• a batholith is a mass of rock formed when a large body of magma cools inside the crust
• the sierra nevada batholith extends for roughly 600 kilometers along the eastern side of california