Ancient Asteroid Impact Reshaped Earth 3.5 Billion Years Ago

There was a time, a time before humans, when the earth was changed by huge asteroid impacts. Evidence of a massive asteroid impact that occurred approximately 3.5 billion years ago (during the Archean era) has been discovered in the Pilbara region of Western Australia. An international team of scientists found small glass beads called spherules in a drill core from the Duffer Formation, which date back to 3.46 billion years ago.

The asteroid is estimated to have been 15 miles (25 km) across and would have created a crater hundreds of miles wide. The impact would have triggered massive earthquakes, huge tsunamis, and widespread destruction. Material from the impact likely spread worldwide and settled in seafloor sediments.

This is the second oldest known asteroid impact on Earth. The oldest impact ejecta deposit, dated at 3.47 billion years old, was previously discovered in the nearby Miralga Creek area. Evidence of asteroid bombardment clusters has been found in sediments from 3.5 to 2.5 billion years ago in the Pilbara Craton and Barberton Mountains in South Africa.

The original impact crater has long been destroyed by tectonic, volcanic, and erosive processes over billions of years. However, these ancient asteroid impacts have left a significant imprint on the evolution of Earth’s early crust. They likely played a major role in shaping the planet’s geology and climate during the Hadean and Archean eons.

While only a small fraction of the impact record has been uncovered so far, the evidence suggests there may have been hundreds of large asteroid impacts in Earth’s first billion years. To put it bluntly, we know it will happen again eventually, and that, if a big enough space rock hits, it could wipe out life on earth. Therefore, we should be spending time and money looking for ways to avoid these lurking dangers.