Presentation on theme: "VOLCANOES VOLCANOES CHAPTER 3 VOLCANOES. OBJECTIVE AND STARTER Objective: Today you will learn about volcanoes and why they form. Starter-KWL Chart K(What."— Presentation transcript:
OBJECTIVE AND STARTER Objective: Today you will learn about volcanoes and why they form. Starter-KWL Chart K(What you Know about Volcanoes W (What you want to learn about Volcanoes) L (What you learned about volcanoes)
Background Information Have you ever seen a volcano? What was happening? Iceland at Night
Volcano A weak spot in the crust where molten material or magma comes to the surface.
Rock Types High in silica Light-colored and slow (too sticky) Examples: Rhyolite Pumice Obsidian Low in silica Dark colored and flows easily Basalt can sometimes form these six- sided columns seen below
Lava When magma reaches the surface. Text pg.97 Examples of lava types Aa
OBJECTIVE Objective: Today you will learn about landforms that are created by volcanoes.
Three Types of Volcanoes “How do they get their names?” Cinder ConeComposite Shield
What kinds of lava are connected with volcano type
Background Information What shape is a volcano? Are all volcanoes shaped like this?
Shield volcano Usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they eruptfluid warrior's shield
Cinder Cone A steep hill like volcano that slopes steeply.
Composite (Strato-) Volcano A volcano built up by many layers (strata) of hardened lava pumice and volcanic ash.
Caldera The huge hole left by a volcanic mountain.
Volcanic Neck It looks like a giant tooth stuck in the ground. Forms when magma hardens a volcano’s pipe.
Dome Mountain - other smaller bodies of magma can create dome mountains which form with rising magma being blocked by horizontal layers of rock. The magma pushes the layers to bend upward into a dome shape. Eventually the rock above the dome wears away, leaving it exposed. One example is the Black Hills in South Dakota.
Dikes, Sills, Batholiths A dike is when magma forces itself across rock layers while magma that squeezes between layers of rock is called a sill. Batholiths are a mass of rock that has been formed when a large body of magma cools inside the crust.