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During the Second World War, linear bands of positive and negative magnetic anomolies were found in the ocean floor, stretching for hundreds of miles, with an almost perfect symmetry either side of mid-ocean ridges. It was realised that these anomalies were evidence of periodic reversals of the earth's magnetic field. Molten basalt had been magnetised in the direction of the field and then cooled to 'fossilise' that direction. Each time the earth's magnetic field reversed, a stripe was added to the 'bar-code'.
By dating onshore lava flows where magnetic reversals had occurred, a timescale of magnetic reversals was built up. It then became clear that, in the undersea anomalies, the youngest rocks were near the ridge, while the oldest were farther away and nearest the continents. Either side of the ridge, stripes of exactly the same age could be matched with each other.
There was already evidence of continental drift, but this new evidence helped to explain how the earth's crust is moving and how the sea floor is spreading.
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What does seafloor spreading have to do with the theory of continental drift?
Seafloor Spreading helped move the Continents to their current location.
How did Alfred Wegeners theory support the theory of seafloor spreading?
Alfred Wegener's theory of continental drift suggested that continents move over time on Earth's surface. This theory provided support for the concept of seafloor spreading, which explains how new oceanic crust forms at mid-ocean ridges and spreads outward. Both theories contributed to the development of the theory of plate tectonics, which explains the large-scale movements of Earth's lithosphere.
How is magnesium used to support the theory of seafloor spreading?
Magnesium is used to support the theory of seafloor spreading because as new oceanic crust forms at mid-ocean ridges, it contains higher levels of magnesium compared to older crust. This can be observed through magnetic anomalies in the oceanic crust, where variations in magnesium content create distinct magnetic stripes that align with the spreading centers. This provides evidence that new crust is being continuously generated at mid-ocean ridges, supporting the process of seafloor spreading.
Which was not included in the support for harry hess's hypothesis of sea-floor spreading?
One key piece of support that was not included in the initial support for Harry Hess's hypothesis of seafloor spreading was the mechanism of plate tectonics. This idea was developed and integrated into the theory of seafloor spreading by geologists like Robert Dietz and J. Tuzo Wilson at a later stage.
Who proposed the theory of seafloor spreading based on maps of the ocean floor?
The theory of seafloor spreading was proposed by Harry Hess, a geologist and Navy officer, in the early 1960s. He proposed that new oceanic crust is formed at mid-ocean ridges and then spreads outward. This theory helped to explain the mechanism behind continental drift and plate tectonics.
How is magnetism used to support the theory about seafloor spreading?
Magnetism is used to support the theory of seafloor spreading through the study of magnetic stripes on the seafloor. These stripes are aligned with the Earth's magnetic field and provide evidence for the process of seafloor spreading, where new oceanic crust is formed at mid-ocean ridges. As the crust cools and solidifies, the magnetic minerals in the rocks align with the Earth's magnetic field, creating a record of magnetic reversals over time that support the theory of seafloor spreading.
How do the ages of the rocks on the ocean floor support the theory of seafloor spreading?
The ages of the rocks become older the farther the way they are from the ridges. The closer they are the younger it is. This leaves evidence to the seafloor spreading theory.
How do the ages of rock on the ocean floor support the theory of seafloor spreading?
The ages of the rocks become older the farther the way they are from the ridges. The closer they are the younger it is. This leaves evidence to the seafloor spreading theory.
What does seafloor spreading have to do with the theory of continental drift?
Seafloor Spreading helped move the Continents to their current location.
How did Alfred Wegeners theory support the theory of seafloor spreading?
Alfred Wegener's theory of continental drift suggested that continents move over time on Earth's surface. This theory provided support for the concept of seafloor spreading, which explains how new oceanic crust forms at mid-ocean ridges and spreads outward. Both theories contributed to the development of the theory of plate tectonics, which explains the large-scale movements of Earth's lithosphere.
How do the ages of the rocks on the seafloor support the theory of seafloor spreading?
The ages of the rocks become older the farther the way they are from the ridges. The closer they are the younger it is. This leaves evidence to the seafloor spreading theory.
What was the two discovery Harry Hess?
The Seafloor Spreading Theory
How is magnesium used to support the theory of seafloor spreading?
Magnesium is used to support the theory of seafloor spreading because as new oceanic crust forms at mid-ocean ridges, it contains higher levels of magnesium compared to older crust. This can be observed through magnetic anomalies in the oceanic crust, where variations in magnesium content create distinct magnetic stripes that align with the spreading centers. This provides evidence that new crust is being continuously generated at mid-ocean ridges, supporting the process of seafloor spreading.
Does the theory of plate tectonics contain both seafloor spreading and continental drift?
Yes. The theory of plate tectonics is very broad, and it covers seafloor spreading, continental drift, plate boundaries and so on.
Which was not included in the support for harry hess's hypothesis of sea-floor spreading?
One key piece of support that was not included in the initial support for Harry Hess's hypothesis of seafloor spreading was the mechanism of plate tectonics. This idea was developed and integrated into the theory of seafloor spreading by geologists like Robert Dietz and J. Tuzo Wilson at a later stage.
Who proposed the theory of seafloor spreading based on maps of the ocean floor?
The theory of seafloor spreading was proposed by Harry Hess, a geologist and Navy officer, in the early 1960s. He proposed that new oceanic crust is formed at mid-ocean ridges and then spreads outward. This theory helped to explain the mechanism behind continental drift and plate tectonics.
Describe how magnetism is used to support the theory of seafloor spreading?
New material is added to the sea floor when sea floor spreading occurs. When the iron cools it is magnetized by the magnetic field of the earth.
