For instance the atlantic ocean is believed to be expanding because of its few trenches.
What causes sea floor spreading.
The motivating force for seafloor spreading ridges is tectonic plate pull rather than magma pressure although there is typically significant magma activity at spreading ridges.
A chain of underwater mountains along which sea floor spreading occurs is a.
As the plates move apart new material wells up and cools onto the edge of the plates.
Seafloor spreading occurs along mid ocean ridges large mountain ranges rising from the ocean floor.
Sea floor spreading and subduction.
Seafloor spreading happens at the bottom of an ocean as tectonic plates move apart.
This idea played a pivotal role in the development of the theory of plate tectonics which revolutionized geologic thought during the last quarter of the 20th century.
In which earth layer are most convection currents that cause seafloor spreading thought to be located.
Due to this continuous seafloor spreading occurs and makes atlantic ocean floor to be connected to other continental crust making the ocean gets wider over the time.
Gravity causes older denser oceanic crust to sink beneath less dense continental crust.
This seafloor spreading hypothesis had been proposed a few years earlier by harry hess a petrologist at princeton university and robert dietz an oceanographer in the us coast and geodetic survey the federal department that made maps of the oceans and us coastlines.
Subduction and sea floor spreading are processes that could alter the size and form of the ocean.
As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading samples collected from the ocean floor show that the age of oceanic crust increases with distance from the spreading centre important evidence in favour of this process.
Oceanic crust on both sides of the ridge shows matching patterns of reversed and normal magnetic polarity.
Which processes change the size and shape of the oceans.
At ridges in the middle of oceans new oceanic crust is created.
The mid atlantic ridge for instance separates the north american plate from the eurasian plate and the south american plate from the african plate the east pacific rise is a mid ocean ridge that runs through the eastern pacific ocean and separates the pacific plate from the north american.
Which evidence causes most scientists to believe that seafloor spreading occurs at the mid atlantic ridge.
The seafloor moves and carries continents with it.
The motivating force for seafloor spreading ridges is tectonic plate slab pull at subduction zones rather than magma pressure although there is typically.
When oceanic plates diverge tensional stress causes fractures to occur in the lithosphere.
These age data also allow the rate of seafloor spreading to be determined and they show that rates.
