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Earth Systems 3209. Reference: Chapters 4, 15, 16, 19; Appendix A & B. Unit: 4 The Forces Within Earth. Unit 4: Topic 5.1. Types of Volcanoes. Focus on . . . define volcano.
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Earth Systems 3209 Reference: Chapters 4, 15, 16, 19; Appendix A & B Unit: 4The Forces Within Earth
Unit 4: Topic 5.1 Types of Volcanoes Focus on . . . • define volcano. • describe the three types of volcanoes based on the following criteria; width, slope, type of material, size and rock type.
Types of Volcanoes • Volcano • is an opening in Earth’s crust through which igneous materials (lava, ash, cinder, and gases) are erupted. • Three different types of volcanoes exist; • Composite • Sheild • Cinder Text Reference Pages 96 - 101
Large, nearly symmetrical structure formed from alternating lava flows and pyroclastic debris. These volcanoes are produced by very viscous (thick) lavas mainly andesitic in composition. Most active composite cones are in a narrow zone that encircles the Pacific (Pacific Ring of fire). 1. Composite or Stratovolcano Characteristics:
These volcanoes are found in mountainous environments where oceanic – continental convergence occurs.Ex. Andes Mountains. Examples of these volcanoes include;Mount Mayon in the Phillipines, Mount Fuji in Japan, and Mount St. Helens In the USA. Display the most violent type of volcanic activity. Erupting lava and pyroclastic material. Form a steep sided and relatively narrow base volcano (up to 20 km wide) compared to shield. 1. Composite or Stratovolcano Characteristics:
Broad, slightly domed structure formed from fluid lava flows. These volcanoes are produced by lavas that display a low viscosity and are mainly basaltic in composition. These volcanoes are mainly found on the ocean floor along divergent boundaries and hot spots. Examples of these volcanoes include;Hawaiian Islands (Mauna Loa and Kilauea), & Midway Islands. Form relatively wide base volcanoes compared to its height and are the largest of the three types of volcanoes. 2. Shield Volcano Characteristics:
Built mainly of ejected pyroclastic materials, such as, ash and cinder. Volcanic cone has a very steep slope that is usually less than 300 meters high. Form on the base of larger volcanoes and are the smallest of the three types of volcanoes. Example: Paricutin in Mexico. 3. Ash & CinderVolcano Characteristics:
A size comparison of the three types of volcanoes Shield volcanoesare the largest reaching up to 100’s of kilometers wide and up to 4 km above sea level. Composite volcanoesare the second largest ranging in size from 10’s of kilometers wide and up to 3 km high. Cinder volcanoesare the smallest approximately 1 – 2 km wide and up to 300 meters (1000 ft) high.
Example 1: Which is a characteristic of a shield volcano? Which type of volcano can be found associated with oceanic ridges? (A) cinder (C) shield (B) composite (D) strata
Example 2: What are small, steep-sided volcanoes made of pyroclastic debris called? (A) calderas (C) composite volcanoes (B) cinder cones (D) shield volcanoes
Your Turn . . . Take the time and complete the following questions . . .(Solutions to follow) Questions: Which type of volcano is the smallest with the steepest slope? (A) cinder (C) composite (B) shield (D) strato At which location is a composite volcano formed? convergent plate boundary (C) hot spot (B) divergent plate boundary (D) mid-ocean ridge
Solutions . . . Questions: Which type of volcano is the smallest with the steepest slope? (A) cinder (C) composite (B) shield (D) strato At which location is a composite volcano formed? convergent plate boundary (C) hot spot (B) divergent plate boundary (D) mid-ocean ridge
Summary . . . Overview of Points covered: • Volcano • is an opening in Earth’s crust through which igneous are erupted. 3 types of Volcanoes:1) Composite 2) Shield 3) Cinder • large, symmetrical • alternating lava flows • & pyroclastic deposits • broad • slightly domed • basaltic lava • ejected pyroclasticmaterials • steeply angled sides • relatively small