Seafloor spreading and subduction
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Transcript of Seafloor spreading and subduction
Seafloor Spreading and Subduction
Continental drift was largely ignored until the 1950s…
• When the USA started mapping the ocean floor properly, using new techniques
• Scientists such as Marie Tharp produced the first detail ocean floor maps
They discovered mountains and valleys they had not expected
This lead to the idea of seafloor spreading
• Scientists such as Harry Hess and Robert Dietz looked at the maps of the ocean floor and developed the idea of seafloor spreading.
Seafloor spreading
Evidence 4 – Magnetic Reversals
Sea-Floor Spreading
Discovery of Sea-Floor Spreading
Sediment thickness
Patterns of Earthquakes
Where does old crust go?
Earthquakes
Depths of earthquake foci
Where Does Ocean Crust Go?
Hugo Benioff, 1954
Benioff’s Interpretation Updated