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.
He supported the Seafloor Spreading Theory by first discovering the Continental Drift Theory.
No
Seafloor Spreading helped move the Continents to their current location.
The Seafloor Spreading Theory was proposed by Harry Hess.
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.
He supported the Seafloor Spreading Theory by first discovering the Continental Drift Theory.
No
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.
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.
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.
Seafloor spreading helped prove the theory of continental drift. Pangea theory also helped.
Seafloor Spreading helped move the Continents to their current location.
The Seafloor Spreading Theory was proposed by Harry Hess.
The Seafloor Spreading Theory
Currently there don't seem to be any.
Yes. The theory of plate tectonics is very broad, and it covers seafloor spreading, continental drift, plate boundaries and so on.
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.