1 Mechanism Explaining Sea Floor Spreading - Basics for Plate Tectonics YouTube Lecture Handouts

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1 Mechanism Explaining Sea Floor Spreading - Basics for Plate Tectonics

Sea Floor Spreading

  • It՚s a theory of lithospheric evolution that holds that the ocean floors are spreading outward from vast underwater ridges.
  • First proposed in the early 1960՚s.
  • Proposed by the American geologist Harry H. Hess.
  • Its major beliefs gave great support to the theory of continental drift.
  • Provided a conceptual base for the development of plate tectonics.
Illustration: 1 Mechanism Explaining Sea Floor Spreading - Basics for Plate Tectonics YouTube Lecture Handouts

Harry H. Hess

  • He was a geologist and a United States Navy officer in World War II.
  • Best known for his theories on sea floor spreading.
  • Specifically work on relationships between island arcs, seafloor gravity anomalies, and serpentinized peridotite.

Europe Continent

Illustration: Europe Continent

Explore the Ocean

Illustration: Explore the Ocean

Seafloor Spreading Model

Illustration: Seafloor Spreading Model

Supporting Evidence for Seafloor Spreading

  • Abundant evidence supports the major contentions of this theory.
  • First, samples of deep ocean floor show that basaltic oceanic crust and superimposing sediment become progressively.
  • Second, rock making up the ocean floor is considerably younger than the continents.

Evidences for Sea Floor Spreading

Illustration: Evidences for Sea Floor Spreading

Evidence Used to Support the Theory of Continental Drift

  • Molten material
  • Radiometric age dating and fossil ages
  • Seafloor drill
  • Magnetic stripes

✍ Manishika