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| <h1>Volcanism</h1>
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| There are three(3) types of lavas formed by volcanoes. Mafic, Intermediate, and Felsic.<br>
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| <B><U>Mafic</B><U>(Basaltic)</U><br>
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| <li>%SiO2: < 50%</li>
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| <li>%FeMg: 4%</li>
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| <li>Temp: up to 1500C</li>
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| <li>Viscosity: Low</li>
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| <li>Eruptive Behavior: gentle</li>
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| <li>Distribution: divergent plate boundries, hot spots, convergent plate boundries</li>
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| <B><U>Intermediate</B><U>(Andesitic)</U><br>
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| <li>%SiO2: ~60%</li>
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| <li>%FeMg: ~3%</li>
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| <li>Temp: ~1000C</li>
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| <li>Viscosity: Intermediate</li>
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| <li>Eruptive Behavior: explosive</li>
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| <li>Distribution: convergent plate boundries</li>
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| <B><U>Felsic</B><U>(Rhyolitic)</U><br>
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| <li>%SiO2: >70%</li>
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| <li>%FeMg: 2%</li>
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| <li>Temp: 700C</li>
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| <li>Viscosity: High</li>
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| <li>Eruptive Behavior: explosive</li>
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| <li>Distribution: hot spots in continental crusts (Yellowstone National Park)</li>
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