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Volcanos - Coggle Diagram

- - - - low in silica
      - very runny
      - flows out in great rivers
      - travels many km before solidifying
      - forms extensive but gently sloping landformes
    - - high in silica
      - viscous
      - flows a short distance
      - landforms produced have steep sides
  - - - mix of dry rock and hot gas
      - flows down at hurricane-force speeds
      - moves away
      - deadliest
    - - dust and ash
      - blasted high into sky
      - remain in sky for and long time
      - transported around the world by wind
      - ash cloud in Iceland (2010) disrupted air traffic in Europe
    - - mudflow
      - ash and dust mixed with rain or steam firm melted snow
      - thick
      - flow down at speed up to 200km/hr
  - - - heaver-than-air gas produced from a lake in Cameroon killed in 25km radius
- - - - ash and cinders rich in minerals
      - natural fertaliser
    - - local economy positively effected
      - produces jobs
      - Yellowstone National Park
    - - see case study for more info
  - - - pyroclastic activty
        
        poisons gases
    - - houses, roads, railways, ect.
    - - ash clouds
      - acid rain
- - - - Larges
      - Formed deep below the crust
      - large volumes of magma intrude into the crust
      - cools and solidifies slowly
      - ourse grained and large crystals
      - granite
    - - dome structure with flat floor
      - magam pushes in-between the strata
      - pressure forses strata to bulge upwards
      - then cool and solid
    - - horizontal sheets of volcanic rock
      - run parallel to strata
      - form close to the surface, less pressure from overlaying rock
      - magma forced into bedding planes
      - cool and solidified
    - - vertical sheets of volcanic rock
      - run periodically in strata
      - magam frced into vertical fractures and faults
      - cool and solidifies
- - - - cones
        
        cone-shaped mountain formed form success eruptions
        
        crated formed (depression) inside the cone
        
        formed during eruption as last of materials drained back into vent
        
        floor may cinsist of lava or solidified materials
        
        parasitic cone = form materials flowing into a secondary vent (formed on the side of the main volcano)
      - domes
        
        formes when acidic, viscous lava erupts
        
        piles up around the vent to form a dome shape
        
        can explode violently releasing hot rock and ash
      - caldera
        
        forms when large amount of magma and gases are blown out onto surface during eruption
        
        enough ejected chamber may become emptie
        
        chamber is unable to support cone above
        
        cone collapses into the chamber
        
        large depression result is called a caldera
      - happens when material spews from a vent (opening) on the surface
      - most occurs at destructive boundaries
      - connected to the magma chamber - main storage area
    - - lava plateaus
        
        falt topped land form risig abouve the surounding area
        
        Antrim-Derry Plateau
      - rising magam will find the easiest escape
      - if rises up through long fissure fountains of lava can form a fire curtain
      - produces large quantities of basic lava
      - covers large area of land
      - Distructive plate boundaries
      - Mid Atlantic sea floor
        
        American and Eurasian plat separating
        
        magma wells up to fill gap
        
        once reaches sea water cools and solidifies
        
        over time build up to form the Mid-Atlantic Ridge
    - - Occurs away from plate bounderies
      - plume rises (column of hot molten rock)
      - plume braks through crust
      - lava erupts forming a cone
      - cones made by basic lava
      - plume stays still while plate moves forming a line of new volcanoes
      - Hawaiian Island chain