Volcanoes Flashcards
Volcanology
◍ escape of molten material from mantle into atmosphere
Instrusive
◍ volcanic material WITHIN the crust
◍ granite
Extrusive
◍ Volcanic material that’s emitted ONTO the surface
◍ Basalt
3 forms of volcanic materials
◍ lava
◍ Pyroclasts
◍ Gases
Lava
◍ magma after it’s gases have been released
Pyroclasts
◍ material ejected from a volcano
◍ Ash,rocks,dust
Gases
◍ Carbon dioxide
◍ Sulfur dioxide
◍ Nitrogen
◍ Chlorine
Hotspots
◍ formed by a narrow stream of magma where there’s a superplum of molten magma rising
◍ plates move new volanic island ontop of hotspot
◍ Hotspot remains in the same place as the plates move
Active volcano
◍currently erupting
◍pacific ring of fire
◍Mount etna in italy
Dormant volcano
◍ hasn’t erupted for ages but still can
◍ mount st. helens in usa
Extint volcano
◍ hasn’t erupted in historic times
◍ Mount slemish in antrim
Silica
◍ material that makes lava thick
◍ made from silicon and oxygen
◍ More silica- more violent eruption
subduction zones
◍ more silica
◍ explosive volcaones
2 types of lava
◍ basic lava
◍acidic lava
Basic lava
◍ low in silica [45-55%]
◍ gases escape easily
◍ gently sloping volcanoes
◍ Usually at constructive plate boundaries
◍ Hawaii
Acidic lava
◍ High in silica [80% ish]
◍ Viscous so doesn’t move freely
◍ Usually at destructive plate boundaries
◍ Cotopaxi in the andes
Pyroclastic material
◍ large volums of ejected material
LAhar
◍ when snow-capped volcano mountains erupt and mix w. snow and pyroclastic material
◍ nevado del ruiz colombia
Composite volcanoes
◍ steep-sided cone
◍ made of alternate layers of lava and pyroclastic material
◍ if crater is blocked top can blow off
◍ Yellowstone national parks in caldera
Dome volcano
◍ steep-sided rounded volcano formed by slow acidic lava
◍ \viscous mature doesn’t flow from crater
◍ mount st. helens
Shield volcano
◍ very wide base and shallow sloping sides
◍ fast flowing basic lava
