Paper I · 4 Geography of India & AP · 4.1.2 Interior of the Earth and plate tectonics

4.1.2.4 Sea-floor spreading and palaeomagnetism

Harry Hess proposed in the early 1960s that new ocean floor forms at mid-oceanic ridges and is consumed at trenches; the matching magnetic stripes on both sides of the ridges, recorded as the Earth's field reversed, proved it and supplied the mechanism Wegener lacked.

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Key terms

  • Harry Hess
  • sea-floor spreading
  • mid-oceanic ridge
  • oceanic trench
  • palaeomagnetism
  • magnetic reversal
  • normal polarity
  • Vine-Matthews
  • abyssal plain
  • continental margin
  • convection currents
  • Arthur Holmes

What this note covers

  1. Core factsFoundation
  2. ExplainedStandard
  3. DeeperAdvanced
  4. Mains writingMains writing
  5. Common trapsFoundation
  6. Quick revisionFoundation

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