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Volcanic Landforms

Volcanic Landforms. Volcanic eruptions create landforms make of lava, ash , and other materials. These land forms include shield, cinder cone, & composite volcanoes (aka stratovolcano) and lava plateaus. Shield volcanoes Thin layers of lava pour out of vents…….

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Volcanic Landforms

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  1. Volcanic Landforms

  2. Volcanic eruptions create landforms make of lava, ash, and other materials.

  3. These land forms include shield, cinder cone, & composite volcanoes (aka stratovolcano) and lava plateaus.

  4. Shield volcanoesThin layers of lava pour out of vents……..

  5. and harden on top of previous layers.

  6. Such flows build a wide, gentle sloping mountain.

  7. (with a profile much like that of a warrior's shield.)

  8. Thousands of eruptions gradually build these volcanoes.

  9. The largestvolcanoes on Earth are shield volcanoes Mauna Loa, Hawaii

  10. and one of the largest known volcanoes in our solar system, Olympus Mons on Mars

  11. Cinder Cone Volcanoes: Lava with high viscosity

  12. may produce ash, cinders and bombs during an explosive eruption.

  13. These materials build up around the vent in a steep, cone-shaped hill mountain.

  14. Paricutin in Mexico erupted in 1943 in a farmer’s cornfield.

  15. Composite Volcanoes: Gentle lava flows may alternate with . . ..

  16. ….explosive eruptions. These result in tall, cone-shaped mountains…..

  17. with alternating layers of lava and ash.

  18. Mt St Helens & Mt Rainier located in the NW of the United States.

  19. Lava Plateau: Instead of forming mountains, some eruptions form high level areas.

  20. Lava flows out of several long cracks over a large area.

  21. This thin, runny lava may travel far before cooling.

  22. After millions of years these lava layers can form high plateaus.

  23. Colorado Plateau of Utah, Colorado, Arizona & New Mexico

  24. Calderas: The huge hole left by the collapse of a volcanic mountain is called a caldera.

  25. During anenormous eruption the main vent and magma chambers may become empty.

  26. The mountain becomes a hollow shell. With nothing to support it, the top collapses.

  27. Soils From Lava and Ash: People often live near an active volcano because of the fertile volcanic soil.

  28. As volcanic materials break down to form soil,

  29. potassium, phosphorus and other nutrients are released into the soil

  30. Some volcanic soils are the richest or the most fertile soils in the world.

  31. Landforms From Magma

  32. Sometimes magma forces its way through cracks in the upper crust but fails to reach the surface.

  33. There the magma cools and hardens into rock.

  34. Overtime, weathering may expose these rock structures.

  35. Volcanic Necks: This looks like a giant tooth stuck in the ground.

  36. Volcanic necks result when a volcanic pipe hardens.

  37. Dikes and Sills: Magma that forces itself across rock layers may form a dike.

  38. Dikes are often seen as a slanting layer of rock, possibly perpendicular to the existing rock.

  39. When magma squeezes between horizontal layers it forms a sill.

  40. Sills are usually parallel to the existing rock layer.

  41. Batholith: Large masses form the core of many mountain ranges.

  42. Fig. 1 shows just how big batholiths can be.

  43. Dome Mountains: A dome mountain forms when uplift pushes a batholith or smaller body of magma toward the surface.

  44. Eventually rock above and around the dome wears away, leaving it exposed.

  45. Hot Springs: Form when water is heated by nearby magma or hot rock.

  46. The hot water rises to the surface and collects in a natural pool.

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