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Land Form Patterns: Volcanic Mountains. Unit 1: Land & Water Forms World Geography 3200/3202. Course Outcomes. In this lesson you will: 1.1.8 Explain what causes a volcano to erupt. (k) 1.1.9 Describe the characteristics of an ash and-cinder cone, a shield cone, and acomposite cone. (k)
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Land Form Patterns: Volcanic Mountains Unit 1: Land & Water Forms World Geography 3200/3202
Course Outcomes • In this lesson you will: • 1.1.8 Explain what causes a volcano to erupt. (k) • 1.1.9 Describe the characteristics of an ash and-cinder cone, a shield cone, and acomposite cone. (k) • 1.1.10 Conclude how the location of active volcanoes is related to places where plates meet. (a)
Terminology • Volcano: An opening in the Earth’s crust through which magma, gases, and ash erupt. • Magma: Molten or melted rock found below Earth’s crust. When magma cools to a solid it forms igneous rocks. • Lava: magma that flows at the Earth’s surface. • Ash : Small pieces of lava that are blasted into the air during volcanic eruptions. • Vent: The opening through which the volcanic material flows.
Types of Volcanoes • Ash & Cinder Cone • Shield Cone • Composite Cone
Ash & Cinder Cone • The simplest type of volcano. • Symmetrical shape, steep sides, large crater. A single vent. • Very explosive. Lava is thick and slow flowing, often blocking the vent Boom!
Shield Cone • Shape is broad and flat. • The volcano is built of lava, which nearly always flows from the vent. • Eruptions are milder / the least explosive.
Composite Cone • Shape is similar to ash and cinder, except it is built of layers of ash, cinder, and lava. • A network of magma vents develop inside, forming mini-volcanoes. • Eruptions can be explosive, followed by periods of quiet activity.
Volcanoes: Review • Which type of volcano is most explosive? Ash & Cinder • Which type of volcano is least explosive? Shield • Which type of volcano is explosive at times and slow flowing lava at times? Composite
Volcanoes: Review • Which type of volcano has the thickest lava? Ash & Cinder • Which type of volcano has the thinnest, most liquid lava? Shield • Which type of volcano often has side vents? Composite • Which type of volcano has the gentlest slope? Shield
Volcanoes: Review • Which type of volcano is steepest? Ash & Cinder • What term is given to the opening of a volcano? Crater • Liquid, fluid, melted rock below the earth's surface is known as: Magma • Liquid, fluid, melted rock that reaches the earth's surface is known as: Lava