Define mantle plume and explain its role in plate tectonics.

Structure of the answer:

  • • Introduction
  • • What is mantle plume.
  • • Draw a diagram depicting mantle plume and plates movements
  • • Role of mantle plume in plate tectonics.
  • • Conclusion.

Key Points:

  • • A mantle plume is an upwelling of abnormally hot rock within the Earth’s mantle.
  • It is a large column of hot rock rising through the mantle.
  • • The heat from the plume causes rocks in the lower lithosphere to melt.
  • • The largest (and most persistent) mantle plumes are presumed to form where a large volume of mantle rock is heated at the core-mantle boundary, about 1,800 miles below the surface, although smaller plumes may originate elsewhere within the mantle.
  • • The rising column of hot rock reaches the base of the lithosphere, where it spreads out, forming a mushroom-shaped cap to the plume.
  • • The overlying lithosphere is pushed up and stretched out as the plume cap spreads.
  • • This has led to the hypothesis that mantle plumes contribute to continental rifting and the formation of ocean basins.
  • • In the context of the alternative “Plate model”, continental breakup is a process integral to plate tectonics, and massive volcanism occurs as a natural consequence when it onsets.
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