Revision as of 16:58, 11 December 2004

Volcanism

There are three(3) types of lavas formed by volcanoes. Mafic, Intermediate, and Felsic.
Mafic(Basaltic)

%SiO2: < 50%

%FeMg: 4%

Temp: up to 1500C

Viscosity: Low

Eruptive Behavior: gentle

Distribution: divergent plate boundries, hot spots, convergent plate boundries

Intermediate(Andesitic)

%SiO2: ~60%

%FeMg: ~3%

Temp: ~1000C

Viscosity: Intermediate

Eruptive Behavior: explosive

Distribution: convergent plate boundries

Felsic(Rhyolitic)

%SiO2: >70%

%FeMg: 2%

Temp: 700C

Viscosity: High

Eruptive Behavior: explosive

Distribution: hot spots in continental crusts (Yellowstone National Park)

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