Question: What Causes Seafloor Spreading?

What causes the plates to move?

The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth’s mantle and fit snugly against one another.

The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other..

How do seafloor spreading and subduction work together?

As subduction occurs, crust closer to a mid-ocean ridge moves away from the ridge and toward a deep-ocean trench. Sea-floor spreading and subduction work together. They move the ocean floor as if it were on a giant conveyor belt. … In the process of subduction, oceanic crust sinks down beneath the trench into the mantle.

Where does seafloor spreading occur quizlet?

Where does seafloor spreading occur? This process occurs along divergent plate boundaries at areas called mid-ocean ridges.

Why does seafloor spreading occur?

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.

What is evidence of seafloor spreading?

Several types of evidence supported Hess’s theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves. This evidence led scientists to look again at Wegener’s hypothesis of continental drift.

What are the 4 evidence of continental drift?

They based their idea of continental drift on several lines of evidence: fit of the continents, paleoclimate indicators, truncated geologic features, and fossils.

Does the Earth get bigger because of seafloor spreading?

New crust is continually being pushed away from divergent boundaries (where sea-floor spreading occurs), increasing Earth’s surface. But the Earth isn’t getting any bigger.

What is the difference between continental drift and seafloor spreading?

Continental drift is a very similar process to seafloor spreading. Continental drift is the gradual movement of continental plates over the Earth’s surface over time. … Seafloor spreading is the formation of new areas of oceanic crust due to the upwelling of magma as oceanic aparts pull apart.

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. … These strips form a pattern that is the same on both sides of the mid-ocean ridge.

What is the average speed of seafloor spreading?

approximately 5 centimeters a yearThe average speed of seafloor spreading is approximately 5 centimeters a year. This growth rate can be compared to the growth rate of human fingernails (Krupicka). The global ridge system consists of oceanic ridges. Seafloor spreading occurs at these elevated oceanic ridges and has high heat flow and volcanism.

What is the source of magma for seafloor spreading?

Sea-floor spreading — In the early 1960s, Princeton geologist Harry Hess proposed the hypothesis of sea-floor spreading, in which basaltic magma from the mantle rises to create new ocean floor at mid-ocean ridges.

What happens when Seafloor spreading occurs?

Sea-floor spreading is what happens at the mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor. As the plates move apart, new material wells up and cools onto the edge of the plates.

Which is the source of new material during the process of seafloor spreading?

Seafloor spreading is the process of molten material from the mantle being pushed upward to the surface of the earth and spreading apart, creating new earth. This process occurs along divergent plate boundaries at areas called mid-ocean ridges .

What causes seafloor spreading and continental drift?

Seafloor spreading helps explain continental drift in the theory of plate tectonics. When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere. … At a spreading center, basaltic magma rises up the fractures and cools on the ocean floor to form new seabed.

What are the steps in the process of seafloor spreading?

What are the steps in the process of sea floor 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.Rock melts to mantle.

How is paleomagnetism evidence of seafloor spreading?

Magnetic reversals show up as bands of alternating polarity in the slowly spreading seafloor. … This explanation of magnetic striping by paleomagnetism convinced scientists that new oceanic crust was being continually formed at mid-oceanic ridges. Seafloor spreading was accepted as a reality.

Where is active seafloor spreading today?

Where is active sea floor spreading occurring today? Seafloor spreading is the movement of old rock that is being pushed by the new young oceanic crust. This would be a divergent since the plates are separating from each other. Active seafloor spreading is occurring at mid-ocean ridges.

Who is responsible for seafloor spreading?

Harry H. HessThe seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Hess in 1960.

What is the major evidence that seafloor spreading creates new lithosphere?

When the Earth’s magnetic field reverses, the magnetized minerals align in the opposite direction. 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.

What boundaries can destroy seafloor?

At convergent plate boundaries, oceanic crust is often forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into granite, the rock that makes up the continents. Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed.

What is the first step in seafloor spreading?

Sea-Floor Spreading begins at a mid-ocean ridge, which forms along a crack in the oceanic crust. along the ridge, molten material that forms several kilometers beneath the surface rises and erupts. at the same time, older rock moves outward on both sides of the ridge.