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Volcanic Rocks of the Anti-Atlas in Morocco Helped Yale University Scientists Solve a Geological Mystery of Half a Billion Years, Showing That the Chaos Came From the Earth’s Magnetic Field and Not From the Continents
For more than half a billion years, one of the greatest enigmas of geology has intrigued scientists: magnetic records in rocks that seemed to contradict all known laws of plate tectonics. Now, an international team led by Yale University claims to have deciphered the mystery.
The answer, it seems, lies in the behavior of the Earth’s magnetic field itself, and not in the movements of the continents.
Ediacaran Period Mystery
The magnetic signatures preserved in the rocks reveal how the Earth’s magnetic field changed and how the continents moved over time.
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However, the geological record of the Ediacaran period—between 630 and 540 million years ago—has always shown extreme and seemingly chaotic variations, as if the continents were moving at an abnormal speed across the planet’s surface.
To clarify these anomalies, the researchers carefully analyzed volcanic rocks from the mountainous region of the Anti-Atlas in Morocco.
This layer-by-layer analysis allowed for a more precise determination of the positions and dates of the magnetic field variations. The result was surprising: the changes occurred in just a few thousand years—a time frame much shorter than previously estimated.
An Erratic Magnetic Field
The data indicate that the phenomenon did not result from unusual movements of the tectonic plates, but from an extremely unstable magnetic field. “We are proposing a new model for the Earth’s magnetic field that finds structure in its variability, rather than simply dismissing it as random chaos,” explained geologist David Evans from Yale University.
The team developed a new statistical method of paleomagnetic analysis, which may be essential for producing more accurate maps of the continents and oceans during the Ediacaran period.
As a result, previous theories—such as the hypothesis of a “true polar wander,” in which the entire Earth’s crust and mantle would move while the poles remained fixed—have been dismissed.
Core Formation and Magnetic Instability
By comparing volcanic samples with sedimentary rocks formed over longer periods, the researchers found that the average positions of the magnetic poles remained relatively stable.
This finding reinforces the hypothesis that the Earth’s magnetic field, and not the continents, was the element in constant change.
The origin of this instability may lie in the continuous formation of the Earth’s core, which was still evolving during the Ediacaran period.
This process would have caused intense fluctuations in the magnetic field, resulting in the erratic behavior recorded in the rocks.
A New Look at Earth’s History
The results obtained represent the most accurate model ever proposed for the behavior of the magnetic field during the Ediacaran period.
In addition to solving a long-standing geological mystery, the research paves the way for new interpretations of the planet’s history.
According to Evans, if the new statistical method proves consistent, it could fill gaps between different geological eras, providing a continuous view of plate tectonics over billions of years.
The study also reinforces the crucial role of the geological record in understanding terrestrial evolution. The rocks not only record plate movements but also reveal when the planet was hit by asteroids and how the first complex life forms emerged.
During the Ediacaran period, these life forms began to appear, and now, thanks to new evidence, we know that what seemed like “strange” behavior of the continents was, in fact, a chaotic phase of the Earth’s magnetic field.
The complete research was published in the journal Science Advances.
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