How Do Igneous Rocks Form?
Go to:
Name ____________________________ Period ______
http://www.classzone.com/books/earth_science/terc/content/investigations/es0603/es0603page01.cfm
Step One - Describe the four igneous rocks shown in the images (use the words color and grain size).
Sample 1 _________________________________________________________________________
Sample 2 _________________________________________________________________________
Sample 3 _________________________________________________________________________
Sample 4 _________________________________________________________________________
Step Two - Click each image to see a larger version plus information about the rock's texture. Add details to your
answers for question 1
Step Three - Read the information on this page.
Step Four - Click each image to examine a larger view of the rock's texture. Identify the texture of each of these
igneous rocks as coarse-grained, fine-grained or porphyritic. Record your answers in the table.
Step Five - Click the labeled features to see microscopic views of igneous crystals forming under different cooling
conditions.
What is true about the rate at which magma cools and its texture?
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Step Six- Click each image to examine the rock's texture and infer its cooling rate and environment.
Identify the cooling rate (fast, slow, or two-staged) and cooling environment (magma chamber, eruption from
volcano, or deep cooling followed by eruption) of the rock in each image. Record your answers in the table.
Rocks texture, cooling Rate &
environment
1.
Rocks texture, cooling Rate &
environment
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Rocks texture, cooling Rate &
environment
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