'Armor' that surrounded Earth 3.7 billion years ago revealed in Greenland

(NLDO) - An extremely important event for our existence on Earth has been recorded in ancient stone tablets.

According to Sci-News, a team of geologists led by the Massachusetts Institute of Technology (MIT - USA) and Oxford University (UK) has found the oldest evidence of the formation of the Earth's magnetic field in ancient rocks in the Isua Supercrust Belt in West Greenland.

Geologists are drilling through ancient rocks in West Greenland to search for evidence of Earth's oldest magnetosphere - Photo: MIT NEWS

The Isua supercrust belt in West Greenland has experienced three thermal events throughout its geological history.

The first event was the most important, when rocks were heated to 550 degrees Celsius about 3.7 billion years ago. That is how the ancient Earth generated its own magnetic field.

Earth's magnetic field is created when molten iron in the outer core mixes with liquid, driven by buoyancy as the inner core solidifies, creating a giant "dynamo."

This process gave the initially bare Earth an invisible layer of armor called the magnetosphere.

The magnetosphere, which protects the planet's surface from the solar wind, has grown over time. Thanks to this protective layer, life has been able to move onto the continents and away from the protection of the oceans.

For example, our neighbor planet Mars, although located in the "habitable zone" of the Solar System, has a very thin and weak magnetosphere, not enough to block harmful cosmic radiation. Therefore, Mars currently does not have Earth-like life.

Paleomagnetic data from rocks in West Greenland also revealed that the magnetic field 3.7 billion years ago had a strength of at least 15 microtesla. For comparison, the Earth's current magnetic field has a strength of 30 microtesla.

These results provide the oldest estimate of Earth's magnetic field strength derived from a whole rock sample, providing a more accurate and reliable assessment than previous studies using individual crystals.

“This is a really important step forward as we try to determine the role of ancient magnetic fields when life on Earth first emerged,” said Professor Claire Nichols from the University of Oxford (UK), a member of the research team.

A significant challenge in reconstructing the Earth's ancient magnetic field is that any event that heats the rock can alter previously preserved signals.

Rocks in the Earth's crust also often have long and complex geologic histories, erasing previous magnetic information.

However, the Isua Supracrust Belt has a unique geology, lying on thick continental crust that protects it from extensive tectonic activity and deformation, thus preserving intact paleomagnetic data.

This data comes from iron grains in the rock, which effectively act as tiny magnets that can record both the strength and direction of the magnetic field as the crystallization process locks them in place.

The results also provide new insights into the role of magnetic fields in shaping the evolution of Earth's atmosphere.

The magnetosphere helps regulate the planet's atmosphere by pushing certain gases out into space and preventing the loss of essential ones, helping to maintain atmospheric balance, which is another necessity for life.

Source: https://nld.com.vn/ao-giap-bao-boc-trai-dat-37-ti-nam-truoc-lo-dien-o-greenland-196240501085048816.htm