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The Lithosphere of Earth. Igneous Processes and Volcanic Activity 1. Why study? • Thermal state • Thermal history • Composition of interior • Geothermal / Hazards • Comparative planetology 2. Volcanism and plate boundaries • Divergent
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The Lithosphere of Earth • Igneous Processes and Volcanic Activity 1. Why study? • Thermal state • Thermal history • Composition of interior • Geothermal / Hazards • Comparative planetology 2. Volcanism and plate boundaries • Divergent - Continental breakup (Flood basalts) - Mid-ocean ridge • Convergent - Domes, flows, explosive, composite volcanoes • Intraplate Volcanism - Strombolian style - Hawaiian style
The Lithosphere of Earth - Volcanism Strombolian Hawaiian Plinian
Volcanic Styles Plinian Activity Strombolian Activity Produces turbulent, buoyant cloud, Rises to great heights Hawaiian Activity Spatter Cone Cinder Cone Atmosphere sucked in, heated Exit velocity high Bubble Rise Rate > Magma Rise Rate Cloud collapses to pyroclastic flows Dome Growth Degasses Low viscosity gas-clast mixture Pressure greatly exceeds atmospheric pressure Fracture & Growth Magma Rise Rate > Gas Rise Rate Brittle lid Viscous gas-rich magma