Seafloor Spreading Quiz

Who were the two scientists who proposed the theory of seafloor spreading in the early 1960s?

• Francis Crick and James Watson

• Joseph John Thomson and Ernest Rutherford

• Harry Hess and Robert Dietz

• Isaac Newton and Albert Eisntein

During the 1960s, scientists were already equipped with gadgets needed to explore the deep ocean. What discovery about the ocean floor is associated with the seafloor spreading?

• Mountains are denser than the mantle.

• The rotational poles of the Earth have migrated.

• The crust of the continents is more dense than the crust of the ocean.

• The crust of the ocean is very young relative to the age of the crust

  of the continents.

Seafloor spreading is a process that creates new_________crust.

• continental

• convergent

• divergent

• oceanic

Convection currents in our Earth's mantle drives the process that moves our _____________.

• core

• crust

• mantle

• mountains

In seafloor spreading, the further the ocean floor is away from the mid-ocean ridge, the _____________________ that floor will be.

• older

• newer

• thinner

• younger

If the Atlantic Ocean is widening at a rate of 3 cm per year, how far (in kilometers) will it spread in a million years?

• 3 kilometers

• 30 kilometers

• 300 kilometers

• 3000 kilometers

Why does the oceanic crust sink beneath the continental crust at the subduction zone?

• The oceanic crust has a greater density.

• The oceanic crust is pushed from the ridge.

• The continental crust has a denser composition.

• The oceanic crust is pulled downward by Earth’s magnetic field.

As the ocean seafloor spreads, the newly formed floor will adapt a specific magnetic signature according to the Earth's magnetic pole at that time. As years pass, lateral segments of seafloor will thus share the same ____________ signature on either side of the mid-oceanic ridge.

• convergent

• divergent

• magnetic

• volcanic

What technology did scientists use in the mid-1900s to map the mid-ocean ridge?

• satellites

• sonar

• submarines

• deep sea diving

The process by which the ocean floor sinks beneath an deep-ocean trench and back into the mantle is known as

• convection

• conduction

• separation

• subduction