Sea-floor Spreading Theory

Question 1

(1960) proposed a radical idea suggesting a process of

Answer 1

Harry Hess, sea-floor spreading.

Question 2

The Sea floor spreading theory states?

This is proof that the plates are moving along on a “?” so Wegner’s idea on continent drift was correct.

Answer 2

t new ocean crust is being created at mid-ocean ridges ( large mountain chains underwater) and (subducted) at deep-sea trenches.
“conveyor belt”

Question 3

Subduction

Answer 3

lithosphere is recycled into the Earth’s mantle at trenches.

Question 4

How does sea-floor spreading works?

Answer 4

Magma comes out the ridge
Magma cools& hardens becoming rock.
Then that rock is pushed away as more new rock is formed
Oceanic crust and continental crust meet at the trench.
Oceanic crust —— under the continental crust- subduction.
Gravity pulls rock —— mantle.
Rock melts to mantle. Process repeats.

Question 5

Evidence molten material

Answer 5

pillow-shaped rocks formed when molten material cools and hardens quickly

Question 6

Evidence-magnetic field

Answer 6

rocks that lie in a pattern showing a record of reversals of magnetic field

Question 7

Evidence-drilling samples

Answer 7

the farther from a ridge the rocks were taken, the older they were

Question 8

Sea-Floor Drilling-

Answer 8

drill samples of rock from the deep-ocean floor.