Chapter 2: Section 2 - Igneous Rocks and the Geologic History of Your Community

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In this section you will find materials that support the implementation of EarthComm, Section 2: Igneous Rocks and the Geologic History of Your Community.

Learning Outcomes

  • Carry out an investigation that determines the most useful properties for describing and identifying different igneous rocks.
  • Carry out an investigation that identifies igneous rock specimens according to their physical properties.
  • Analyze data on a geologic map and legend to locate igneous rocks
  • Obtain information about how the formation of igneous rocks is connected to plate tectonic processes.

Inquiring Further

  1. To learn more about Ship Rock, Sierra Nevada Batholith, and Devil’s Postpile, visit the following web sites:

Ship Rock, New Mexico Bureau of Geology & Mineral Resources

Yosemite National Park, California, NPS

Devil's Postpile National Monument, California, NPS


To learn more about this topic, visit the following web sites:

The Nature of Igneous Rocks

Igneous Rocks, Oregon State
View a slide show about igneous rocks. This is part of a series of lessons called "Rocks and Minerals."

Igneous Rocks by Setting, USGS
Describes the two major settings relative to the surface of igneous rocks.

National Parks and Monuments Composed of Igneous Rocks, National Park Service
From Acadia on the Atlantic Coast to Hawaii in the Pacific, explore the sites of past and present volcanic activity.

Magma, Lava, and Igneous Rocks

Magma, National Geographic
Images and descriptions of magma. Includes summaries of magma in the news.

Magma, Lava, Lava Flows, Lava Lakes, etc., USGS
Use the Volcano Hazards glossary to learn more about lava and the hazards associated with lava flows.

Classifying Igneous Rocks

Atlas of Igneous and Metamorphic Rocks, Minerals, and Textures, University of North Carolina
View microscopic images of plutonic rocks (intrusive igneous rocks) and volcanic rocks (extrusive igneous rocks).

Volcanic Rocks, Glendale Community College
Contains an informative chart, pictures, links, and descriptions of the different classifications of igneous rocks.

Color/Texture Identification Key, James Madison University
Color and texture are one way of classifying igneous rocks. Use this chart to find the name of an igneous rock using simple terms.