For this chapter's Internet Exercise, you will have an opportunity to interact with a Bowen's Reaction Series Simulator. This will allow you to explore interrelations between magma chemical composition, cooling rate, and other magmatic processes such as fractionation.

You can also create a variety of igneous rock textures by varying the cooling rate during the crystallization process. Thus, using this remarkable simulator, you can gain insight into the complex processes that account for the bewildering variety of igneous rocks.

1. Go to the Bowen's Reaction Series Simulator and read the introductory chapters. Once you feel comfortable with the instructions, click on the "here" button to begin the simulation. Note that you must move the cooling rate slide bar before anything will happen. Once you have positioned the cooling rate bar, you will see the temperature begin to decrease.

2. For your first effort, try creating a rock by placing the composition slide bar at Mafic and the cooling rate slide bar at 4 or 5. Allow the simulation to run to its completion. What is the final mineral composition of your rock? What rock name would you apply to this combination of minerals? Do you think this rock is coarse grained or fine-grained? How does this texture affect the name you give to the rock?

3. To reset the simulator, you will need to click on the refresh button for your browser. Once you have done this, set the composition slide bar to Intermediate and the cooling rate slide bar to 4 or 5. Allow the simulation to run to its completion. What is the final mineral composition of your rock? What rock name would you apply to this combination of minerals? Do you think this rock is coarse grained or fine-grained? How does this texture affect the name you give to the rock?

4. Reset the simulator again. Move the composition slide bar to Felsic and the cooling rate slide bar to 4 or 5. Allow the simulation to run to its completion. What is the final mineral composition of your rock? What rock name would you apply to this combination of minerals? Do you think this rock is coarse grained or fine-grained? How does this texture affect the name you give to the rock?

5. Now that you are getting the hang of it, try to create a rock with porphyritic texture. Is this easier to do from a mafic, intermediate, or felsic magma?

6. Reset the simulator and create obsidian. Next try to create basalt. Can you get the cooling rate and composition correct to generate andesite?

It's not as simple as you thought it would be to create various igneous rocks, is it?