In a geomagnetic reversal, the south and north magnetic poles flip locations. A magnetic pole reversal takes place every 450,000 years on average, but this is not regular. We are way overdue since the last reversal was 780,000 years ago. There is a pattern in the magnetic polarity of basaltic rocks on opposite sides of a mid-ocean ridge. Basalt contains tiny magnetic crystals that point to the location of the north magnetic pole at the time the lava cools. The rocks at the ridge have positive polarity, but on either side of the ridge the polarity is negative, indicating that those lavas cooled when the magnetic field was opposite of what it is today. On either side of the basalt with negative polarity are more rocks with positive polarity. This pattern continues on both sides of the mid-ocean ridge across the ocean basin. The pattern of magnetic polarity is one of the main lines of evidence for seafloor spreading, which is the mechanism for plate tectonics.
The polarity of the Earth's magnetic field is recorded in igneous rocks, and reversals.
True. These are known as magnetic reversals. Please see the related link for more information.
What can reverse magnetic polarity
Magnetic reversals and sea floor spreading.
the theory of sea-floor spreading
The polarity of the Earth's magnetic field is recorded in igneous rocks, and reversals.
The polarity of the Earth's magnetic field is recorded in igneous rocks, and reversals.
The theory proposed by Henry Hess was supported with magnetic polarity reversals
The north pole becomes the south pole and vice versa. Also any rocks cooling in the reversed field will trap the magnetic polarity prevalent at their time of cooling. This means we can can trace the history of past magnetic reversals.
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True. These are known as magnetic reversals. Please see the related link for more information.
pole reversals seafloor spreading
What can reverse magnetic polarity
Caused by changes in earth's magnetic field over time, especially reversals of the magnetic poles.
Caused by changes in earth's magnetic field over time, especially reversals of the magnetic poles.
Caused by changes in earth's magnetic field over time, especially reversals of the magnetic poles.
Magnetic reversals and sea floor spreading.