GEOL 2390 Chapter Notes - Chapter 9: Lahar, Mount Pinatubo, Magma Chamber

• School: University of Manitoba
• Department: Geological Sciences
• Course: GEOL 2390
• Professor: William M.Last

Document Summary

Composite volcano or stratovolcano shield with shallow slopes. Cone-shaped steep sides, build up of lava flows and pyroclastic molten rock including a small component of dissolved gasses (mostly water vapor and co2. Magma that has emerged from volcano onto earths surface. Andesite combination of lava flows and explosive activity. Cone shaped, steep sides often with summit crater low low. Volcano origins volcanism at mid-oceanic ridges form shield volcanoes with basaltic rock. Above hot spots located below the lithospheric plates forms shield volcanoes with basaltic rock. Subduction zones associated with andesite rock form composite volcanoes producing rock with intermediate silica when mixed with crusts basalt rock. Caldera-forming eruptions are extremely explosive and violent, associated with rhyolitic rocks, associated with volcanic domes inland of subduction zones. Depressions commonly found at the top of volcanoes formed by explosion or collapse of the upper portion of the volcanic cone and may be flat floored or funnel shaped (usually a few km)