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
Strombolian Activity
Hawaiian Activity
Plinian Activity
Dome Growth
Spatter Cone
Bubble Rise Rate > Magma Rise Rate
Cinder Cone
Magma Rise Rate > Gas Rise Rate
Produces turbulent, buoyant cloud,
Rises to great heights
Atmosphere sucked in, heated
Exit velocity high
Low viscosity gas-clast mixture
Pressure greatly exceeds atmospheric pressure
Cloud collapses to pyroclastic flows
Brittle lid
DegassesFracture & Growth
Viscous gas-rich magma