Ancient Lava Reveals Facts about Earth's Magnetic Field that People Rarely Know


 The Earth's magnetic field is always changing in direction and strength. How quickly these changes occur, is something that is very interesting, given the features of the planet Earth to protect us all from cosmic radiation.

Ancient lava flows in eastern Scotland fill some important gaps in the history of our magnetic field. This new analysis of lava flows supports previous research showing a 200-million-year cycle, in which Earth's magnetic field weakens and then strengthens again.


In this study, the team also used the magnetic history they found buried in the geological record to double-check other measurements made over the past few decades, and to map the history of Earth's magnetic field back about 500 million years.



"Our findings, when considered in conjunction with existing data sets, support the existence of a long cycle of about 200 million years of Earth's magnetic field strength associated with inner-Earth processes," said paleomagnetist Louise Hawkin of the University of Liverpool in the UK. , Monday (23/8/2021).


Thermal and microwave paleomagnetic analysis techniques were used on rock samples from ancient lava flows with alignment of mineral crystals within them, revealing the state of Earth's magnetic field at the time they were originally formed.


The team found that between 332 million and 416 million years ago, there was a decline in the magnetic field that matched another from 120 million years ago. During the previous period (now called the Mid-Palaeozoic Dipole low/MPDL), the field surrounding the Earth was about a quarter of its current strength.

The dates match a 200-million-year cycle, and provide experts with some important new insights into how the magnetic field behaved more than 300 million years ago, leading up to the Superchron (an extended period of time when the field remained stable).


"This comprehensive magnetic analysis of the Strathmore and Kinghorn lava flows is key to filling the period leading up to the Kiman Superchron, a period in which the geomagnetic poles were stable and did not reverse for about 50 million years," Hawkins said.


If this cycle is true, and the magnetic poles reverse or tend to occur every 200,000-300,000 years, we will actually experience another cycle that is not yet clear what effect it will have on all of today's technology and gadgets. To note, changes in the Earth's magnetic field, one of which has an impact on the GPS signal on the cellphone. This has also caught the attention of researchers.



The more we know about the history of the Earth's magnetic field in general, the better we can predict what will happen next. If our force field against space radiation starts to cause problems, we need to find out as early as possible.

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