August M
Our planet has a remarkable way of hiding its oldest memories deep underground.
For billions of years, ancient geological layers have silently preserved the evidence of cosmic collisions that helped shape the course of our planet’s early history, reports The Guardian.
Deep time capsule
A group of researchers in Australia just uncovered one of these secrets. According to a report by The Guardian, scientists have found definitive evidence of the oldest known meteorite impact crater on Earth.
The colossal strike occurred three billion years ago in Western Australia’s remote Pilbara region. This discovery officially pushes back the timeline for known planetary impacts.
Previously, an Australian site called Yarrabubba held the record at 2.2 billion years old. The newly dated North Pole Dome crater shatters that milestone by hundreds of millions of years.
Cosmic detective work
To pinpoint the exact timing of the crash, the research team from Curtin University turned to advanced microscopic analysis. They examined unique geological features called shatter cones and published their findings in the Geology journal.
Geologist Chris Kirkland led the study and explained that these rare rock formations serve as an incredible historical archive. He noted that they offer “a rare glimpse of the violent processes that shaped the early Earth”.
The team used a specialized ion probe to analyze tiny crystals embedded in volcanic rock. Kirkland emphasized the unique nature of the site, stating, “There’s very few places that are these deep time capsules that let us peer into the formative processes on our planet. That’s why they’re quite special.”
The smoking gun
When the space rock slammed into the ground, the extreme heat reshaped minerals called zircon and apatite. These tiny crystals warped into skeletal patterns that match samples recovered from the moon.
During this ancient era, Earth looked entirely different than it does today. It was mostly a vast water world with very little dry land, a dimmer sun, and a much closer moon.
Macquarie University geochemist Bruce Schaefer compared the study to a classic mystery investigation. He pointed out that while the moon still shows its old scars, erosion has wiped away most ancient evidence on Earth.
Schaefer praised the clever method of tracking both minerals to confirm the date. He concluded, “The fact those two were reset at the same time is the really powerful evidence that this is the age of that event. The apatite and the zircon together is what’s, if you like, the smoking gun.”
Sources: The Guardian
