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Volcanoes

Volcanoes. Geography 12 Ms. Inden. Volcanology; volcanologist. The study of the ways solid, liquid or gaseous materials are forced into the earth's crust or ejected onto the surface; a person who does this studying. A few terms. Molten – melted

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Volcanoes

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  1. Volcanoes Geography 12 Ms. Inden

  2. Volcanology; volcanologist The study of the ways solid, liquid or gaseous materials are forced into the earth's crust or ejected onto the surface; a person who does this studying

  3. A few terms • Molten – melted • Magma – molten rock when it is still underground • Lava – magma that has reached the surface http://www1.moe.edu.sg/learn@/Quest/winners/primary/yu_neng_pri_volcano_nc/qpixa.jpg

  4. Where does magma come from? • Radioactive decay or uranium and thorium • Friction created by the movement of plates • The magma develops in a magma chamber below the earth http://www.georesources.co.uk/volgen.htm

  5. Ka-boom! • The rock expands as the temperature rises, and also gas is produced • This causes pressure underground • The magma will erupt (now lava), along with gasses, steam, ash, volcanic bombs and rock fragments • The eruption, and the violence involved depends on the sort of volcano the type of rock involved (more on this later)

  6. Animation of a strata volcano • http://www.pbs.org/wnet/savageearth/animations/volcanoes/index.html

  7. When magma is injected into the crust (never reaching the surface), it is called intrusive Form intrusive igneous rock when cooled Sometimes exposed through erosion Extrusive Intrusive • When lava or other materials reach the surface they are called extrusive • Form extrusive igneous rock when cooled

  8. You need to know batholith, laccolith, sill and dike Which landforms on this image are intrusive, and which are extrusive? What would cause a batholith to be exposed? http://www.indiana.edu/~geol105/images/gaia_chapter_5/dike&sill.jpg

  9. Intrusive landforms • Most magma is intruded • Intrusive igneous rock has bigger crystals than lava which is cooled quickly at the surface • Batholith – at least 100 km, magma cools slowly • Sill – horizontal intrusion • Dikes – cuts through bedding planes vertically • Laccolith – smaller than batholith - fills up a chamber or cavern

  10. This volcanic flow probably ran into a glacier, or possibly a cliff – this part of the lava cooled quicker, creating these columns • Look for columns like this on the highway toward Vancouver – south of Quesnel

  11. Giant’s Causeway in Northern Ireland http://www.geolsoc.org.uk/webdav/site/GSL/shared/images/geoscientist/GiantsCausewayrersized.jpg

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