VOLCANOES, Eruptions and Igneous Features

Volcanoes.htm

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Volcanoes Volcanoes.htm

Video

http://video.nationalgeographic.com/video/player/environment/environment-natural-disasters/volcanoes/volcano-eruptions.html

Locations of volcanoes

http://www.dartmouth.edu/~volcano/

http://www.cotf.edu/ete/modules/volcanoes/vlocation.html

Definition

• a mountain that forms when magma reaches the earth’s surface

Cascade Range from Northern California to Washington

http://vulcan.wr.usgs.gov/Volcanoes/Cascades/ImageMaps/CascadeRange/cascade_range.html

Mt. St. Helens, May 1980

• http://www.fs.fed.us/gpnf/volcanocams/msh/

Kilauea in Hawaii

• http://hvo.wr.usgs.gov/kilauea/
• http://www.pbs.org/wnet/nature/episodes/kilauea-mountain-of-fire/video-full-episode/4825/ ( 50 minute video)

http://www.volcanolive.com/

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Formation of volcano

• mantle rock melts forming magma, which rises up through the crust, erupting at the surface as a volcano
  ( it rises because it is less dense than the surrounding rock)
  
• structure of volcano
• Magma chamber
• Pipe
• Vent
• http://www.decadevolcano.net/photos/keywords/vent.htm
• Caldera
• http://vulcan.wr.usgs.gov/Glossary/Caldera/description_caldera.html
• Crater

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Type of eruption

• Quiet Eruption
• Magma that is very hot, low in silica content, creates lava flow
• Pahoehoe lava, hot fast moving lava with ropeli
• http://www.geology.sdsu.edu/how_volcanoes_work/Basaltic_lava.html
• http://www.geology.sdsu.edu/how_volcanoes_work/Pyroflows.html
• Aa, cooler, slow moving lava with chunky appearance
• http://www.britannica.com/EBchecked/topic/332564/lava

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Location and types of volcanoes

http://vulcan.wr.usgs.gov/Glossary/VolcanoTypes/volcano_types.html

http://www.msnucleus.org/membership/html/k-6/pt/volcanoes/6/ptv6_2a.html

Most volcanoes occur along plate boundaries or at hot spots in the crust

• Ring of Fire
• http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/Maps/map_plate_tectonics_world.html

http://www.worldatlas.com/aatlas/infopage/ringfire.htm

Hot spots – a region where hot rock extends from deep within the mantle to the surface

Shield volcano – flat, wide volcano formed by quiet eruption of low-viscosity lava

http://vulcan.wr.usgs.gov/Glossary/ShieldVolcano/description_shield_volcano.html

Cinder cone volcano-small, steep sided volcano formed by ash and cinders

http://www.windows.ucar.edu/cgi-bin/tour_def/earth/interior/cinder_cone.html

Composite volcano – formed from explosive eruptions, that produce a combination of lava and ash

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Other Igneous Features http://www.australianmuseum.net.au/igneous-intrusions

batholith – largest type of intrusive igneous rock mass, often form the core of a mountain range, such as the Sierra Nevada range in California

http://www.encyclopedia.com/topic/batholith.aspx

sill – magma that hardens in rock cracks parallel to existing rock

http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Notes/dikes_sills.html

dike – magma that hardens in rock cracks perpendicular to existing rock

volcanic neck – when magma hardens in a volcano’s pipe

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