Volcanic records showed the complexity of magnetic field reversal.
The last reversal of Earth’s magnetic poles occurred long before man could record them, but exploring the flow of the ancient lava has helped scientists estimate the duration of this strange phenomenon. A research team used volcanic records to study Earth’s last magnetic reversal, which occurred about 780,000 years ago. They found that this flip may have taken much longer than the researchers thought so far, the scientists reported in a new study. Earth’s magnetic field has turned dozens of times over the past 2.5 million years, with North turning to the south and vice versa. Scientists know that the last reversal took place during the Stone Age, but they have little information about the duration of this phenomenon and when the next “blow” could occur. In the new study, the researchers relied on flow sequences of lava that erupted near or during the last reversal to measure their duration. Using this method, they estimated that the inversion took 22,000 years – much longer than the previous estimates of 1,000 to 10,000 years. We found that the last reversal was more complex and had begun earlier in the Earth’s outer core than previously thought, “said Bradley Singer, a professor of Earth Sciences at the University of Wisconsin-Madison, to Space.com. While conducting studies on a volcano in Chile in 1993, Singer encountered one of the lava flow sequences that recorded part of the reversal process. While attempting to date the lava, Singer noticed strange directions of transition of the magnetic field in the lava flow sequences. Such records are indeed extremely rare, and I am one of very few people who go out with them, “said Singer. Since then, he has set a goal to better explain the timing of magnetic field reversals. The inversion occurs when iron molecules in the rotating outer core of the Earth go in the opposite direction as other iron molecules around them. As the number increases, these molecules balance the magnetic field in the Earth’s core. (If this happened today, it would render the compass useless as the needle would swing from the North Pole to the South Pole.) During this process, the Earth’s magnetic field, which protects the planet from hot sun particles and solar radiation, becomes weaker. This type of duration would mean that shielding the earth from solar radiation would be very complex and, on average, less effective over an extended period of time, “said John Tarduno, professor of geophysics at the University of Rochester, who did not According to the study, Space.com said, “The real effects are still controversial and they are not as tragic or extreme as anyone might suspect, but they can still have important implications.” Some of these effects, said Singer, could include genetic mutations or additional stress on certain animal or plant species or possible extinction due to increased exposure to harmful ultraviolet sunlight. An increase in sun particles entering the earth’s atmosphere could also lead to interference from satellites and other communication systems such as radio and GPS, he added. Recent reports of the magnetic field jerking from the Canadian Arctic to Siberia have sparked a debate over whether the next magnetic field reversal is imminent and how it will affect life on Earth. However, Singer dismissed these claims. “There is little evidence to suggest that this recent decline in field strength or the rapid shift in the North Pole’s position reflects behavior that suggests a polarity reversal over the next 2000 years imminent, “he said.Geologists can use the data obtained from lava flows to learn much more about magnetic field reversals. “Although volcano records are not complete records, they are still the best type of record we keep for a period of time Tarduno said, “Greater accuracy in age dating and the ability to get more detailed records of [the inversions] make the community think a lot,” he added. The paper was published on Aug. 7 in Science Advances.