magnetic field reversals

Cultural

Changes in direction or orientation of the magnetic field of the Earth that have occurred from time to time. (Several hundred are known in the geological record.) Sometimes the north magnetic pole is near the geographic North Pole and sometimes near the South Pole in Antarctica.

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The causes of these reversals are not known in detail, but are thought to be related to the motion of fluids in the Earth's core.

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Over the past 250 Ma, there have a few hundred magnetic field reversals, and their timing has been anything but regular.

From Textbooks • Jan. 1, 2015

Figure 8.19 The last 5 Ma of magnetic field reversals.

From Textbooks • Jan. 1, 2015

It was also shown that the patterns corresponded with the chronology of Earth’s magnetic field reversals.

From Textbooks • Jan. 1, 2015

Magnetic chronology is based on the known record of Earth’s magnetic field reversals.

From Textbooks • Jan. 1, 2015

By studying magnetism in volcanic rocks that have been dated isotopically, geologists have been able to delineate the chronology of magnetic field reversals going back for some 250 Ma.

From Textbooks • Jan. 1, 2015

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