What are the steps in the process of sea-floor spreading? 1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge. 3. Older rock moves outward on both sides of the ridge. 4. Molten material cools and forms a strip of solid rock in the centre of the ridge.
- 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.
What are the steps in the process of seafloor spreading?
What are the steps in the process of sea-floor spreading? 1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge. 3. Older rock moves outward on both sides of the ridge. 4. Molten material cools and forms a strip of solid rock in the centre of the ridge.
How would you describe the process of seafloor spreading?
Seafloor spreading is the process by which new oceanic lithosphere forms at mid-ocean ridges. As tectonic plates move away from each other, magma rises from Earth’s interior. It then cools and solidifies in the center of the ridge. The rising magma pushes up between the plates and drives them further apart.
How does sea floor spreading create a new ocean floor?
Seafloor Spreading is the usual process at work at divergent plate boundaries, leading to the creation of new ocean floor. As two tectonic plates slowly separate, molten material rises up from within the mantle to fill the opening. In this way the rugged volcanic landscape of a mid-ocean ridge is created along the plate boundary.
What are the causes of sea floor spreading?
What are the strongest evidence for seafloor spreading?
- Molten material. Hess’s discovery on the warmer temperature near the mid-Atlantic ridge when he began the ocean mapping, led to his evidence about the molten material underneath the ocean. …
- Seafloor drill. …
- Radiometric age dating and fossil ages. …
- Magnetic stripes.
Where does seafloor spreading occur?
What evidence supports the seafloor spreading theory?
What evidence supports Hess's theory of seafloor spreading?
What is the process that Hess proposed?
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What is the process of sea floor spreading?
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.
What is the first step of sea floor spreading?
1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge.
What is the process by which the ocean floor sinks into the mantle?
Subduction is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle.
What are the steps in the formation of a mid-ocean ridge?
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 are the 4 steps of seafloor spreading?
Terms in this set (7) 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.
Listed below are the steps involved in the process of seafloor ...
Listed below are the steps involved in the process of seafloor spreading. Which choice has the steps in the correct order? 1. The seafloor at a subduction - 135…
What is the process of seafloor spreading?
Seafloor Spreading. Seafloor spreading is a geologic process in which tectonic plate s—large slabs of Earth's lithosphere —split apart from each other. Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churn ing motion of Earth’s mantle.
What happens to the seafloor when convection currents move away from each other?
As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense.
How does oceanic crust affect sea level?
As oceanic crust moves away from the shallow mid-ocean ridges, it cools and sinks as it becomes more dense. This increases the volume of the ocean basin and decreases the sea level.
What are the features of the oceanic crust?
Geographic Features. Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading. As it move s, it becomes cooler, more dense, and more thick. Eventually, older oceanic crust encounters a tectonic boundary with continental crust. In some cases, oceanic crust encounters an active plate margin.
Which plate is the Mid Atlantic Ridge?
The oceanic crust of the Mid-Atlantic Ridge, for instance, will either become part of the passive margin on the North American plate (on the east coast of North America) or the Eurasian plate (on the west coast of Europe). New geographic features can be created through seafloor spreading.
How fast does the Mid Atlantic Ridge spread?
The Mid-Atlantic Ridge, for instance, is a slow spreading center. It spreads 2-5 centimeters (.8-2 inches) every year and forms an ocean trench about the size of the Grand Canyon. The East Pacific Rise, on the other hand, is a fast spreading center. It spreads about 6-16 centimeters (3-6 inches) every year.
Is seafloor spreading consistent?
Seafloor spreading is not consistent at all mid-ocean ridges. Slowly spreading ridges are the sites of tall, narrow underwater cliff s and mountains. Rapidly spreading ridges have a much more gentle slopes. The Mid-Atlantic Ridge, for instance, is a slow spreading center.
What is the Seafloor Spreading Theory?
What is seafloor spreading theory? When looking at a map of the Atlantic Ocean, it looks like the continents could fit together like a puzzle.
Who Discovered Seafloor Spreading?
The discovery of seafloor spreading is credited to Harry Hess, who first proposed the idea in the early 1960s. During World War II, Hess had been an admiral in the Navy, traveling aboard vessels that used sonar to locate German U-boats. Since he was also a geologist, he was naturally interested in ocean floor topography as well.
Seafloor Spreading Diagram
The force that causes seafloor spreading and the moving of continents and tectonic plates originates at the earth's extremely hot, dense core. This heat energy transfers out through the layers within the earth. At a certain level within the upper mantle, the heat causes the material to melt and become molten.
Evidence of Seafloor Spreading
Scientists have collected and studied a great deal of data since Hess first proposed his idea of seafloor spreading. They have studied the ages of the rock making up the oceanic crust and the sediment lying on top of it; they have examined the magnetic orientation of iron crystals in the rocks at various locations.
What Is Sea Floor Spreading?
The crusty surface of the cake is similar to the earth's tectonic plates, which are gigantic, slowly-moving pieces of the earth's crust. The uncooked 'batter' between the plates would be the magma. When the magma cools, it becomes part of the earth's crust. Where the plates are moving away from each other, they are called divergent plates. The shifting divergent plates under the ocean are the reason for sea floor spreading.
Why does magma cool during sea floor spreading?
As magma cools during sea floor spreading, it would take on the magnetism of the moment. Knowing the new rock was forming at different times helped explain sea floor spreading and the slow movement of continents. The earth's crust is not stagnant. Large plates, called tectonic plates, are on the move.
Why did scientists find that the Earth's magnetic field shifts occasionally?
Rocks that form at different times may have different magnetism. When it was discovered that the rock near mid-ocean ridges wasn't aligning in one direction, they theorized that the rock was forming at different times. As magma cools during sea floor spreading, it would take on the magnetism of the moment. Knowing the new rock was forming at different times helped explain sea floor spreading and the slow movement of continents.
How did the Red Sea come into existence?
Wherever the sea floor is spreading, the edges move apart while the magma in the middle hardens. That means the rock in the center is the youngest. As the continents move apart , whole new oceans can form. Scientists believe that's how the Red Sea came into existence.
What is the crusty surface of a cake?
The crusty surface of the cake is similar to the earth's tectonic plates, which are gigantic, slowly-moving pieces of the earth's crust. The uncooked 'batter' between the plates would be the magma. When the magma cools, it becomes part of the earth's crust.
What are the mid ocean ridges?
Think of them as underwater mountain chains. One of the more well-known mid-ocean ridges is the Mid-Atlantic Ridge . It splits the North American and Eurasian plates apart in the North, and the South American and African plates in the South. But there is a global mid-ocean ridge system which looks like a series of global zippers that the Mid-Atlantic Ridge is part of.
When were mid ocean ridges discovered?
First came the discovery of mid-ocean ridges in the 1950s. Before that, people assumed the land below the ocean was flat and unchanging, but it was the discovery of strange magnetic anomalies along the ridges that required an explanation. The magnetism in the rocks was not lining up as expected.
Where does seafloor spreading occur?
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.
What evidence supports the seafloor spreading theory?
Abundant evidence supports the major contentions of the seafloor-spreading theory. First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.
What evidence supports Hess's theory 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 is the process that Hess proposed?
In 1960, Hess proposed a radical idea. He suggested that a process he called sea-floor spreading continually adds new material to the ocean floor. In sea- floor spreading, the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. This material hardens to form the rock of the ocean floor.
