GS1 › Physical Geography in Depth

Revision note: Earth's Interior, Continental Drift and Plate Tectonics

  • Seismic: P (fastest, all media), S (solids only), surface waves (most damage); S-shadow beyond 105°, P-shadow 105°–145°
  • Layers: crust (sial/sima), mantle to 2,900 km (asthenosphere), outer core liquid, inner core solid (nife)
  • Discontinuities: Conrad, Moho, Gutenberg, Lehmann
  • Wegener 1912: Pangaea, Panthalassa, Laurasia/Gondwana; evidence – fit, fossils (Mesosaurus, Glossopteris), tillite
  • Hess: sea-floor spreading; palaeomagnetic stripes; Holmes convection
  • 7 major plates; divergent (Mid-Atlantic), convergent (Andes, Japan, Himalayas), transform (San Andreas)
  • India: left Gondwana ~140 Ma, Deccan Traps ~65 Ma (Réunion hotspot), collision ~50 Ma, ~5 cm/yr now
Revision card summarising Earth's Interior, Continental Drift and Plate Tectonics
One-page visual summary of the key points to revise.

Source: https://upscprep.in/upsc/gs1/physical-geography-in-depth/earths-interior-continental-drift-and-plate-tectonics/ · UPSCPrep.in

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