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How magneteism is used to support the theory of seafloor spreading?
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.
What is used as evidence for sea-floor spreading-?
The rocks on either side of a mid-ocean ridge record the direction of the Earth's magnetic field at the time they were formed, and form a pattern of 'magnetic stripes' on either side of the ridge which are symmetrical. It is also now possible to measure ocean widths with sufficient accuracy to show yearly changes.
What does magnetic striping tell us about the age of rocks?
If you know how many stripes away from the mid-ocean ridge the rock is and you know how frequently the earth's poles flip you can use the stripes like rings on a tree to measure the age of that rock.
Why electric field breaks the space-inversion symmetry while magnetic field breaks the time-reversal symmetry?
Electric field breaks space-inversion symmetry because it changes the sign of charges under spatial inversion. Magnetic field breaks time-reversal symmetry because reversing the direction of time changes the direction of the field's rotation or flux lines.
Does electricity always produce a magnetic force?
Magnetism, an aspect of electromagnetism, one of the fundamental forces of nature. Objects such as a bar magnet can influence other magnetic materials, without physically connecting them, because magnetic objects produce a magnetic field. Magnetic fields are usually represented by magnetic flux lines. Magnetic fields influence magnetic materials and also influence charged particles that move through the magnetic field.
Identify how magnetic symmetry can be used as evidence of sea floor spreading?
As the sea floor spreads the magnetic orientation in the rocks as they cooled is preserved. As the earth's magnetic field changes then a distinct pattern is imprinted in the rocks. If sea floor spreading is true then this unique pattern should be the same on both sides from the spreading point. Measurements of sea bottom rocks verify this symmetry is true. :)
Identify how magnetic symmetry can be used as evidence of sea-floor spreading?
On each side of the mid-ocean ridge is a mirror of the striped pattern on the other side. When drawn, these patterns show alternating bands of normal and reverse polarity that match the geomagnetic reversal time scale, scientists can assign ages to the sea-floor rocks. The youngest rocks were at the center, and the older rocks father away. The ages of the sea floor rocks are symmetrical. The only place on the ocean-floor where new rocks are formed are at the rift in mid-ocean ridge. hope this helps :)
How magneteism is used to support the theory of seafloor spreading?
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.
Why do earth's magnetic pole reversals provide evidence of plate tectonics?
Iron gains magnetism at a certain temperature known as the curie point. at this point Iron rich minerals align with the magnetic polls. Today Iron minerals have been found in older rocks pointing in a variety of directions and since our polls do not move this provided evidence that the Continents containing those minerals have moved and after lining up these magnetic rocks with others from the same time they all correlate with Continental drift and plate tech-tonics.
What is used as evidence for sea-floor spreading-?
The rocks on either side of a mid-ocean ridge record the direction of the Earth's magnetic field at the time they were formed, and form a pattern of 'magnetic stripes' on either side of the ridge which are symmetrical. It is also now possible to measure ocean widths with sufficient accuracy to show yearly changes.
What is magnetic symmetry?
Something that goes through the Atlantic ocean.
Does body symmetry affect athletic ability?
There is some evidence that body symmetry has an effect on atheletic ability.
What does magnetic striping tell us about the age of rocks?
If you know how many stripes away from the mid-ocean ridge the rock is and you know how frequently the earth's poles flip you can use the stripes like rings on a tree to measure the age of that rock.
Why electric field breaks the space-inversion symmetry while magnetic field breaks the time-reversal symmetry?
Electric field breaks space-inversion symmetry because it changes the sign of charges under spatial inversion. Magnetic field breaks time-reversal symmetry because reversing the direction of time changes the direction of the field's rotation or flux lines.
Are Maxwell's equations symmetrical?
Yes, Maxwell's equations exhibit a degree of symmetry, particularly in how they describe electric and magnetic fields. They reveal a duality between electricity and magnetism, as the equations governing electric fields (Gauss's law and Faraday's law) have corresponding magnetic counterparts (Gauss's law for magnetism and Ampère's law with Maxwell's addition). This symmetry is further emphasized by their form in the relativistic framework, where electric and magnetic fields transform into each other under changes of reference frame. However, it’s important to note that the equations do not exhibit complete symmetry due to the absence of magnetic monopoles in classical electromagnetism.
How can rocks tell how the polarity of the earth has changed?
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 in the opposite direction.
How magnetic symmetry can be used as evidence of sea-flooring spreading?
On each side of the mid-ocean ridge is a mirror of the striped pattern on the other side. When drawn, these patterns show alternating bands of normal and reverse polarity that match the geomagnetic reversal time scale, scientists can assign ages to the sea-floor rocks. The youngest rocks were at the center, and the older rocks father away. The ages of the sea floor rocks are symmetrical. The only place on the ocean-floor where new rocks are formed are at the rift in mid-ocean ridge. hope this helps :)
