seafloor spreading

seafloor spreading, theory of lithospheric evolution that holds that the ocean floors are spreading outward from vast underwater ridges. First proposed in the early 1960s by the American geologist Harry H. Hess, its major tenets gave great support to the theory of continental drift and provided a conceptual base for the development of plate tectonics.

Sections in this article:

• Introduction
• Discovery of the Mid-Ocean Ridges
• Role of the Spreading Center
• Supporting Evidence for Seafloor Spreading
• Bibliography

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