Development of a Theory: Continental Drift & Seafloor Spreading

Sonar

What technology was used during WWII to detect enemy submarines and produce the first map of the seafloor?

How the continents moved

Wegener could not prove what?

Harry Hess

Who was the scientist that came up with the theory of seafloor spreading?

Subducts

When one tectonic plate __________ under another at a convergent boundary it sinks back in the mantle.

Sediment, magnetic seafloor stripes, age of rocks

What 3 kinds of evidence were used to prove that the seafloor spread?

Magnetic stripes

When the Earth's Magnetic field reverses, evidence for sea-floor spreading is provided by ___________.

Deep ocean trench

A deep valley along the ocean floor is called a __________.

Mid-ocean ridges

According to the theory of seafloor spreading, hot less dense material rises toward the surface at____________. The youngest rock in the ocean floor is found here.

Sea Floor Spreading

Continental drift occurs because of ________.

was completely flat

Before echo sounders, scientists thought topography of the seafloor

Magnetic Reversal

During a ___, the lines of magnetic force run the opposite way.

World War II

Seafloor maps were first made using data gathered during the historical event called ____________.

In the early 1960s, Princeton geologist Harry Hess proposed the hypothesis of sea-floor spreading, in which basaltic magma from the mantle rises to create new ocean floor at mid-ocean ridges. On each side of the ridge, sea floor moves from the ridge towards the deep-sea trenches, where it is subducted and recycled back into the mantle.

Describe the seafloor spreading hypothesis.