What Causes The Ocean Floor To Spread?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises often forming a mountain or elevated area of the seafloor. Eventually the crust cracks.Jun 8 2015
What causes seafloor spreading quizlet?
During sea-floor spreading magma erupts along a mid-ocean ridge to form new oceanic lithosphere. The floor then moves away from the ridge often toward a trench at the edge of the ocean basin. … The pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.
What plate causes ocean floors to expand?
Mid-ocean ridges occur along divergent plate boundaries where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate molten rock rises to the seafloor producing enormous volcanic eruptions of basalt.
What causes the seafloor to spread and continents to drift?
| Question | Answer |
|---|---|
| The primary force that causes the seafloor to spread and continents to drift | Thermal convection |
| Plate | Tectonics |
| The zone below the list of fear is more plastic then the lithosphere so it is easier to bend | Asthenosphere |
| Zones place where the seafloor is forced under continental plates | Subduction |
What causes the ocean floor to deepen?
During seafloor spreading lithosphere and mantle cooling contraction and isostatic adjustment with age cause seafloor deepening. … In addition the cooling plate model explains the almost constant depth and heat flow observed in very old seafloor and lithosphere.
What causes tectonic plates to move?
What causes the seafloor to spread apart at mid ocean ridges quizlet?
What causes the sea floor to spread apart at mid-ocean ranges? Hot magma rises through the boundaries at the mid-ocean ranges creating new rock as it cools and pushing the plates apart.
What is sea floor spreading theory?
What causes paleomagnetic stripes to form on the ocean floor?
Magnetic stripes are the result of reversals of the Earth’s field and seafloor spreading. New oceanic crust is magnetized as it forms and then it moves away from the ridge in both directions. The models show a ridge (a) about 5 million years ago (b) about 2 million years ago and (c) in the present.
What causes the old ocean floor or old rock plunges at the subduction zone?
Oceanic crust is denser than continental crust. At a subduction zone the oceanic crust usually sinks into the mantle beneath lighter continental crust. (Sometimes oceanic crust may grow so old and that dense that it collapses and spontaneously forms a subduction zone scientists think.)
How is new ocean floor created?
As plates converge one plate may move under the other causing earthquakes forming volcanoes or creating deep ocean trenches. Where plates diverge from each other molten magma flows upward between the plates forming mid-ocean ridges underwater volcanoes hydrothermal vents and new ocean floor crust.
When sea floor spreading occurs new crust is added to the ocean floor?
Terms in this set (21) What is the process of sea-floor spreading? In sea-floor spreading the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. As a result the ocean floors move like conveyor belts carrying the continents along with them.
What is the bottom of the sea called?
What’s beneath the ocean floor?
Features of the ocean include the continental shelf slope and rise. The ocean floor is called the abyssal plain. Below the ocean floor there are a few small deeper areas called ocean trenches. Features rising up from the ocean floor include seamounts volcanic islands and the mid-oceanic ridges and rises.
Where is new ocean floor formed?
mid-ocean ridges
Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
Why isnt the ocean floor older?
What are three causes of plate movement?
Mantle dynamics gravity and Earth’s rotation taken altogether causes the plate movements. However convectional currents are the general thought for the motion.
What force causes most of the plate movement?
Research has shown that the major driving force for most plate movement is slab pull because the plates with more of their edges being subducted are the faster-moving ones. However ridge push is also presented in recent research to be a force that drives the movement of plates.
What causes the tectonic plates to move quizlet?
convection currents are a process in which the materials inside the mantle heat up and rise to the surface whilst the cooler liquid sinks as it sinks it then heats up and rises again. This continuous cycle is established: hot liquid rising cold liquid descending. These currents cause the tectonic plates to move.
What is the major evidence that sea-floor spreading creates new lithosphere explain your answer?
The record of magnetic reversals is carried away from each side of the spreading center of a mid-ocean ridge showing that the molten rock is creating new lithosphere.
Which of the following is a result of sea-floor spreading?
In sea-floor spreading the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. As a result the ocean floors move like conveyor belts carrying the continents along with them. … Yet some areas of the deep-ocean floor are teeming with life. One of these areas is the East Pacific Rise.
What causes magnetic stripes on the seafloor quizlet?
Why does the rock of the ocean floor have a pattern of magnetic stripes? The rock of the ocean floor contains iron. As molten material cooled and hardenend the iron bits inside lined up in the direction of Earth’s magnetic poles creating a pattern of magnetized stripes.
What are three kinds of evidence of the ocean floor spreading?
Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading-evidence from molten material magnetic stripes and drilling samples.
How was sea-floor spreading tested as a hypothesis?
Since the oldest oceanic crust was found at the edges of the trenches Hess hypothesized that the seafloor subducts into Earth’s interior at the trenches to be recycled in the mantle. As oceanic crust forms and spreads moving away from the ridge crest it pushes the continent away from the ridge axis.
What causes new material to form at a mid-ocean ridge on the ocean floor?
A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.
How did Vine and Matthews relate the sea floor spreading hypothesis to magnetic reversals of the Earth’s poles?
Vine and Matthews observed that there were symmetrical bands of rocks with similar polarities on each side of every mid-ocean ridge. They hypothesized that the reverse polarized rocks formed at the ridges during the geologic past when the earth’s magnetic field had reverse polarization.
What causes polar wandering?
What causes continents to move Hess?
Photo: Harry Hess argues that the continents had once been one and have drifted apart. … After much thought he proposed in 1960 that the movement of the continents was a result of sea-floor spreading. In 1962 he added a geologic mechanism to account for Wegener’s moving continents.
What is the primary reason that oceanic crust subducts beneath continental crust?
When an oceanic plate converges with a continental plate the oceanic crust will always subduct under the continental crust this is because oceanic crust is naturally denser. Convergent boundaries are commonly associated with larger earthquakes and higher volcanic activity.
What causes subduction?
Subduction occurs when two plates collide at a convergent boundary and one plate is driven beneath the other back into the Earth’s interior. … When an oceanic plate collides with a continental plate the denser oceanic plate is bent downward and slides under the edge of the continent.
What causes the subduction of one of the oceanic plates?
When an oceanic and a continental plate collide eventually the oceanic plate is subducted under the continental plate due to the high density of the oceanic plate. Once again a benioff zone forms where there are shallow intermediate and deep focus earthquakes.
How is the ocean floor destroyed?
What type of rock are sea floors made up of?
The top layer of the sea floor is primarily composed of about 50 % basalt which is the most common type of volcanic rock to be erupted.
Which is the first step in the sea floor spreading process?
1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge.
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