Earth Sciences 1022A/B Lecture 4: Lecture 4 - Volcanoes
Document Summary
Y eruptions occur because of: volcanic gases collect in magma chamber and eruption relieves the. co2, hso4, etc. y magma chemical composition determines type of eruption: pyroclastic explosive. viscous, felsic magma: lava runny, mafic magma. Volcanic structures y types of volcanoes: shield. mixed materials y lava flows and pyroclastics. found at subduction zones/where mountains are being formed. Fissure eruptions y pour lava onto land to build up lava plateaus y usually on sides of a volcano y lava curtains y builds up layers and eventually a plateau y e. g. Yellowstone national park, snake river plain and colombia river basalts, Intrusive igneous bodies y forms plutons with two orientations: discordant cut across host rocks, concordant parallel to host rocks y types of plutons, dykes. discordant smaller y can be produced at subduction zones y many produced at divergent zones e. g.