How is seafloor spreading explained and proven?
Seafloor spreading is the mechanism by which new seafloor lithosphere is constantly being created at mid-ocean ridges. This theory, introduced by Harry Hess, was proven as patterns of magnetic field polarity preserved in seafloor basalt and by age dating of the rocks.
What is the main idea of seafloor spreading?
Seafloor spreading, theory that oceanic crust forms along submarine mountain zones, known collectively as the mid-ocean ridge system, and spreads out laterally away from them.
What are the 4 steps of seafloor spreading?
What are the 4 steps of seafloor spreading?
- Magma comes out of the rift valley.
- Magma cools to rock and hardens.
- Rock is pushed away as new rock is formed at MOR.
- Oceanic crust and continental crust meet at the trench.
- Oceanic crust bends down under the continental crust.
- Gravity pulls rock towards mantle.
Which is the first step in seafloor spreading process?
The first step in the seafloor spreading comes in the form of cracking up of the oceanic crust. The convection currents manage to push huge amounts of magma under very high pressure and the crust breaks up.
What are the two types of seafloor spreading?
Continued spreading and subduction As new seafloor forms and spreads apart from the mid-ocean ridge it slowly cools over time. Older seafloor is, therefore, colder than new seafloor, and older oceanic basins deeper than new oceanic basins due to isostasy.
Which ocean is growing in size which is shrinking explain why this is occurring?
Pacific Ocean
What ocean is growing in size?
The Atlantic Ocean grows 1.5 inches wider every year. That’s because the tectonic plates undergirding the Americas are separating from those beneath Europe and Africa.
How much will the Pacific Ocean shrink in 100 years?
But the Pacific Ocean is slowly shrinking at a rate of 0.5 square kilometers (0.19 square miles) per year due to Plate Tectonics.
Which ocean is increasing most in size over time?
Arctic