Oldest evidence of Earth's magnetic field discovered by researchers

Written by Copernical Team Sunday, 28 April 2024 16:35

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London, UK (SPX) Apr 25, 2024

Researchers at the University of Oxford and MIT have identified a 3.7-billion-year-old geological record of Earth's magnetic field, which closely resembles the current geomagnetic field in its characteristics. This discovery, published in the Journal of Geophysical Research, offers the earliest confirmed measurement of the magnetic field's strength, recorded at 15 microtesla, nearly half of toda

Oldest evidence of Earth's magnetic field discovered by researchers
by Sophie Jenkins
London, UK (SPX) Apr 25, 2024

Researchers at the University of Oxford and MIT have identified a 3.7-billion-year-old geological record of Earth's magnetic field, which closely resembles the current geomagnetic field in its characteristics. This discovery, published in the Journal of Geophysical Research, offers the earliest confirmed measurement of the magnetic field's strength, recorded at 15 microtesla, nearly half of today's strength of 30 microtesla.

The study focused on ancient iron-rich rocks from Greenland, which due to their magnetic properties, provide a historical record of the magnetic field's intensity and direction. The significance of Earth's magnetic field lies in its role in protecting the planet from harmful cosmic radiation and solar winds, which are critical for sustaining life on Earth.

Professor Claire Nichols of the Department of Earth Sciences at Oxford stated, "Extracting reliable records from rocks this old is extremely challenging, and it was really exciting to see primary magnetic signals begin to emerge when we analyzed these samples in the lab. This is a really important step forward as we try and determine the role of the ancient magnetic field when life on Earth was first emerging."

Further findings suggest that despite the solar wind being stronger in the past, Earth's magnetic field has provided consistent protection, potentially allowing life to thrive on land earlier than previously thought. The study also explores the dynamo process driven by the Earth's molten outer core, which is crucial for generating the magnetic field.

This research not only provides insights into the historical functionality of Earth's magnetic field but also into broader geological and atmospheric conditions that may have influenced life's development on the planet. Future research aims to extend these findings by examining rock sequences from other parts of the world to better understand the magnetic field's evolution before the rise of oxygen in the atmosphere.

Research Report:Possible Eoarchean records of the geomagnetic field preserved in the Isua Supracrustal Belt, southern west Greenland