Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Earth Systems 3209 Unit: 4 The Forces Within Earth Reference: Chapters 4, 15, 16, 19; Appendix A & B

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Types of Volcanoes Unit 4: Topic 5.1 Focus on...  define volcano.  describe the three types of volcanoes based on the following criteria; width, slope, type of material, size and rock type.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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; 1)Composite 2)Sheild 3)Cinder Types of Volcanoes Text Reference Pages

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 1. Composite or Stratovolcano 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).  Characteristics :

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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.  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.  1. Composite or Stratovolcano Characteristics :

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Mt. St. Helens – a typical composite volcano

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Mt. St. Helens following the 1980 eruption

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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.  Form relatively wide base volcanoes compared to its height and are the largest of the three types of volcanoes.  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.  2. Shield Volcano Characteristics :

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 2. Shield Volcano

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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 & Cinder Volcano Characteristics :

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador A size comparison of the three types of volcanoes Composite volcanoes are the second largest ranging in size from 10’s of kilometers wide and up to 3 km high. Shield volcanoes are the largest reaching up to 100’s of kilometers wide and up to 4 km above sea level. Cinder volcanoes are the smallest approximately 1 – 2 km wide and up to 300 meters (1000 ft) high.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Volcano Type Characteristics

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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 Width of BaseSlope (A)narrowgentle (B)narrowsteep (C)widegentle (D)widesteep

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Example 2: What are small, steep-sided volcanoes made of pyroclastic debris called? (A) calderas (C) composite volcanoes (B) cinder cones (D) shield volcanoes

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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? (A)convergent plate boundary(C) hot spot (B) divergent plate boundary (D) mid-ocean ridge

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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? (A)convergent plate boundary(C) hot spot (B) divergent plate boundary (D) mid-ocean ridge

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 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) Shield3) Cinder u broad u slightly domed u basaltic lava u ejected pyroclastic materials u steeply angled sides u relatively small u large, symmetrical u alternating lava flows & pyroclastic deposits