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A powerpoint about Volcanic Regions.
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VolcanicRegions
VOLCANIC REGIONS
Recall mid ocean ridges
What happens as oceanic crust spreads?
GSC 350Fall 2013
VOLCANIC REGIONS
Mid ocean ridges
Plates are moving apart Creating area of low pressure which brings up
higher pressured material
Magma is generally representative of mantleWhy?
Recall pillow basalt- lava that solidifies under water and has a pillow-like appearance.
GSC 350Fall 2013
VOLCANIC REGIONS
Recall subduction zones
What happens as the oceanic crust moves into the mantle?
GSC 350Fall 2013
VOLCANIC REGIONS
Subduction zones
Oceanic crust contains basalt, eroded sediments, and fluids.Heats up at ~100km depth, fluids boil off and rise
through the mantle and overriding crust.
Subduction magmas contain recycled material and water (the content which determines volcanic activity)
GSC 350Fall 2013
VOLCANIC REGIONS
Hotspots-
GSC 350Fall 2013
Hotspots
Rising mantle plume of super heated mantle material
Generally very pure magmas representative of mantle material (although can pick up fluids and continental material)
Consider Yellowstone (midcontinent) and Hawaii (mid ocean)
GSC 350Fall 2013VOLCANIC REGIONS
GSC 350Fall 2013VOLCANIC REGIONS
GSC 350Fall 2013
Hawaii-Emperor seamount chain
- Increases in ageto the North-west
- Increases inwater depth
The plate is movingover the hotspot
VOLCANIC REGIONS
VOLCANIC REGIONSGSC 350Fall 2013
Volcano forming regions
VOLCANIC REGIONSGSC 350Fall 2013
Next time Volcanoes and how natural disastersaffect us
Slide Number 1Volcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regionsVolcanic regions