ERTH 2401 Lecture : Lecture Notes 17 Eruptive Styles and Landforms I.doc

• School: Carleton University
• Department: Earth Sciences
• Course: ERTH 2401
• Professor: Claudia Schroder- Adams

Document Summary

Internal heat: volcanoes are a mechanism by which. Earth expels internal heat quickly: internal heat increases with depth. Anomalously hot zones: hot spots, spreading centers. Decrease p (most important mechanism: decompression melting. Phase change from solid to liquid accompanied by volume expansion. Volcanic eruption: sudden occurrence of a violent discharge of volcanic materials. Step by step: hot, solid rock from asthenosphere rises closer to the surface. Pressure decrease causes rocks to melt partially. More rocks liquefy: volatiles gradually come out of the melt. Gas bubbles push magma upward: magma fragments. Powerful gas jet expels magma in the atmosphere. Eruptive style: style: peaceful vs explosive, relation between:tectonic environment, magma composition, eruptive style. Caution: a volcano can change eruption type through time: relation between: eruptive style, eruption type, magma composition, volcanic explo- sivity index. 3 vs: factors controlling volcanism and volcanic landforms, viscosity, volatiles. Peaceful eruptive style: viscosity, low/medium magma viscosity, volatiles, low/medium volatile content, volume of magma, small to large volume.