Download Challenge and Extension - Effingham County Schools

SECTION
VOLCANOES FORM AS MOLTEN ROCK ERUPTS.
8.2 Challenge and Extension
BIG IDEA Mountains and volcanoes form as tectonic plates move.
KEY CONCEPT Volcanoes form as molten rock erupts.
Identify Volcano Types There are three main types of volcanoes: cinder cone,
composite, and shield. Each type has certain characteristics that distinguish it from
the others. The table below describes the three types of volcanoes. Use it to identify
the volcanoes and answer the questions.
Volcano Type A
Volcano Type B
Volcano Type C
Magma is rich in gases; eruption
throws many magma chunks into
the air that harden into rock
Magma is thin and flows easily
Magma is thick and resists flowing
Has steep sides; cone shaped
Broad and flat, with gently sloping
sides
Cone-shaped near top and flattened
near bottom
Made of loose piles of volcanic rock
fragments
Made of many thin layers of lava
Made of layers of lava and layers of
rock fragments
2. Identify volcano Type A. Does it usually erupt explosively? Explain how you know.
3. Identify Volcano B. Is this volcano’s lava low or high in silica? How do you know?
THE CHANGING EARTH, CHAPTER 8, CHALLENGE AND EXTENSION 161
CHAPTER 8
Mountains and Volcanoes
Copyright © by McDougal Littell, a division of Houghton Mifflin Company
1. Identify Volcano C. Why did you choose this volcano type?