Lava records magnetic field reflection

Mohammad ALHADDAD

The Earth's magnetic field appears to be stable, accurate, and reliable enough to navigate, but nevertheless changes dramatically and reflects its polarity (the magnetic north moves to the geographic South Pole, and eventually returns again) every several thousand years.

This reversal has occurred countless times throughout Earth's history, but scientists have little information on its causes and how it occurred.

The magnetic field is currently experiencing a period of turbulence and weakness manifested in signs that the magnetic north pole is currently heading towards Siberia in Russia, which forced the GPS recently to update its software sooner than expected to take place.

Turbulent magnetic period
A recent geological study published August 7 in the journal Science Advances by researchers from the University of Wisconsin-Madison and Japanese researchers suggests that the most recent reflection in the Earth's magnetic field occurred about 770,000 years ago, and took at least 22 A thousand years to complete.

Based on the advances in global measurement and survey tools for lava flows, ocean sediments and the Antarctic ice cores, the new study provides a detailed look at a turbulent period in relation to the Earth's magnetic field.

For thousands of years, the magnetic field weakened and partially changed, then stabilized again, reversing it to the direction we know today.

The results gave the researchers a clearer and more accurate picture, at a time when they believe we are currently witnessing early stages of a period of weakness and change of the magnetic field, similar to those that occurred in the geological history of the Earth.

Reflections usually arise in the deepest parts of the earth, but the effects are clearly visible on the Earth's surface and in the atmosphere.

Unless we have a complete and high-resolution record of the shape of field reflection on the Earth's surface, it will be difficult to even discuss what mechanisms of reflection originate.

The Earth's magnetic field is produced by liquid iron in the outer core of the Earth, which orbits the solid inner core. This dynamic action creates a more stable field passing through the North and South poles, but the field shifts and weakens significantly during reflections.

Volcanic record
When new rocks are formed - usually when lava flows or sedimentation on the seabed - they record the magnetic field at the time of their formation.

Geologists can scan this global record to compile the history of magnetic fields dating back millions of years. These rocks are an annotated record that tells the story of the reflections that have occurred in the Earth's magnetic field, especially the more recent reflection called the Matioma Bronhas.

In the current study, researchers focused on lava flows from Chile, Tahiti, Hawaii, the Caribbean and the Canary Islands.

The team collected samples of these lava flows over several seasons.The lava flows are ideal records of the magnetic field.It contains a lot of heat-bearing minerals, and when they cool they trap the direction of the field, but it is a sporadic record, as volcanoes do not erupt continuously.

The researchers collected magnetic readings and the history of radioactive isotopes of samples from seven consecutive chains of lava flows, to recreate the magnetic field over a period of about 770,000 years centered on the reflection of Matoyama Bronhas, based on developed methods developed in the Laboratory of Historical Geography at the University of Wisconsin. By measuring argon resulting from the decomposition of radioactive potassium in rocks.

The researchers found that the most recent reversal was rapid by geological criteria, taking 22 thousand years to complete its occurrence, more than twice the time suggested by recent studies, which is 9 thousand years.

The results of the study suggest that the reflection of the Earth's magnetic field may significantly affect the movement of navigation, satellite communications, and terrestrial communications, and therefore, as the study says, the world will have an opportunity to adapt to a long period of magnetic instability, is the period of this change.