Discovery of a massive 3.5-billion-year-old crater, the origin of life? 🌍

In Australia, a team of researchers has identified the oldest meteorite impact crater ever discovered. This site, located in the Pilbara region, dates back 3.5 billion years, pushing the boundaries of our understanding of Earth's early history.

This discovery, published in Nature Communications, is based on undeniable geological evidence. It sheds light not only on the history of meteorite impacts but also on their potential role in the evolution of Earth's crust and the emergence of life.

A colossal impact

Researchers have identified "shock cones," unique rock formations resulting from the extreme pressure generated by an impact, shaped like badminton shuttlecocks. These structures, located near Marble Bar, indicate that a meteor struck Earth at over 22,000 mph (36,000 km/h), creating a crater more than 62 miles (100 km) in diameter. The violence of the collision ejected debris across the planet, permanently altering Earth's environment.

The energy released by this event had major geological consequences. According to scientists, the impact may have influenced the formation of the first continents by disrupting the Earth's crust. This collision could also have promoted the rise of magma from the mantle, contributing to the creation of stable zones called cratons.

These cratons, which today form the cores of continents, highlight the importance of meteorite impacts in Earth's early evolution. This discovery also emphasizes that such events, though destructive, may have played a key role in shaping our planet.

A link to the origin of life?

Impact craters may have played a key role in the emergence of life. The environments created by these collisions, such as mineral-rich hot water basins, would have been conducive to the development of microorganisms. These conditions could have favored the first microbial life forms over 3.5 billion years ago.

Researchers suggest that the energy released by the impact generated hydrothermal zones, similar to those where life thrives today. These environments, combined with heat and nutrients, would have provided an ideal setting for the emergence of life. This hypothesis opens new perspectives on the origins of terrestrial biology.

This discovery reinforces the idea that meteorite impacts are not solely destructive events. They could have been essential catalysts in the formation of primitive ecosystems. By studying other ancient craters, scientists hope to better understand how life may have emerged and developed on Earth.

To go further: What is a shock cone?

Shock cones are cone-shaped rock structures formed under extreme pressure. They are created only during meteorite impacts or nuclear explosions, making them reliable geological markers. Their presence is considered undeniable evidence of a major impact event.

These formations are characterized by radiating striations or lines emanating from the cone's apex. They result from the propagation of shock waves through the rock, deforming its internal structure. Shock cones are often well-preserved in stable geological environments, such as those in the Pilbara region of Australia.

The study of shock cones allows scientists to reconstruct the conditions of an impact, such as the direction and intensity of the collision. This information is essential for understanding the history of meteorite impacts on Earth and their influence on the planet's evolution.

What is a craton?

Cratons are ancient and stable continental masses formed several billion years ago. They constitute the cores of current continents and are characterized by their resistance to tectonic deformation. These geological structures preserve valuable information about Earth's primitive history.

These regions are typically composed of very ancient rocks, often over 2.5 billion years old. Cratons are often covered by more recent sedimentary layers, but their base remains unchanged. Their stability makes them unique geological archives for studying the planet's early ages.

Cratons play a key role in understanding the formation of continents. They may have formed in response to major meteorite impacts, which could have triggered geological processes such as subduction or magma upwelling. Their study helps to better understand the evolution of Earth's crust and the conditions that allowed life to emerge.