Untitled Flashcards Set

15.15 Volcanoes

A. Volcano: opening in the earth’s crust from which molten rock pours.

   1. Magma: molten rock under the surface

   2. Lava: molten rock above the surface

   3. Volcanoes have conical shapes   ( What type of rock doesn’t take chemical weathering? ) What two countries are more likely to have earthquakes? Japan, turkey, new York, )

  4. Crater: depression at the summit

B. Volcanic ash can effect the earth’s climate

   Gas and ash are the deadliest product of a volcano

C. Factors affecting volcanic violence

    1. Viscosity: the thickness of the lava – lava contain large amount of silica will become sticky, if the lava doesn’t have silica, it will be runny

    2. Dissolved gases

    3. Increasing viscosity and gas content increases the violence of the eruption

D. notable volcanoes

   1. Mt. St. Helens, mt st helens is growing up, still an active volcano

   2. Yellowstone- a super volcano, still active, has magma beneath the surface

E. Volcanic rocks

    1. Fine grained

    2. Basalt: most common volcanic rock

    3. Pumice: Light porous igneous rock

F. Volcanic regions

  1.” Ring of fire”, Iceland, mediterranean, and East Africa  

  2. 530 Active volcanoes in the world today

  3. on average,50 eruptions per year

15.16 Intrusive rocks- igneous rock

A. Plutons: bodies of solidified magma

   1. cooled slowly- coarse grained rock

   2. coarse grained

   3. Granite- form from solidified magma

B. Evidence granite was once molten

    1. Same mineral composition and pattern, the only extension is size of crystals

    2, smooth transitions into volcanic rock

    3. Intrusions into sedimentary rock

    4. Evidence that intruded sedimentary rock experience heat