3 Billion-Year-Old Mystery Solved: Earth's Oldest Crater Identified

Geologists have determined and officially confirmed the age of the oldest meteorite crater on Earth. We are talking about the North Pole Dome ancient impact crater located in the region. The results of this study were published in the Geology scientific journal.

According to calculations by a team of researchers led by scientist Christopher Kirkland from Curtin University, a massive meteorite struck this area approximately 3.02 billion years ago. If this result is fully confirmed, this structure will go down in history as the only meteorite crater with a precisely determined age.

Scientists note that one of the main pieces of evidence found in the area is shatter cones. Such structures are formed in rocks only under high pressure caused by massive celestial bodies striking the Earth at high speeds. They were found in the Pilbara region, one of the rare places on Earth where rocks older than 3 billion years are preserved.

However, for many years, the exact timing of this impact has been a subject of debate among scientists. This is because the age of the basalt rocks in the formation has not been directly determined, and estimates provided by various scientific groups differed by nearly three billion years. existed.

To clarify this issue, researchers conducted an in-depth analysis of zircon, apatite, calcite, and muscovite minerals in the rocks. Zircon crystals, in particular, provided crucial information. They contained both ancient crystals older than 3.4 billion years and younger "skeletal" grains formed as a result of rapid cooling during the meteorite impact.

These best-preserved zircons showed an age of approximately 3024 ± 7 million years. At the same time, the apatite mineral formed as a result of hydrothermal processes also confirmed an age of nearly 3019 million years. The fact that two independent mineral analyses yielded the same result is considered the strongest scientific evidence that the meteorite struck the Earth during this exact period.

As another important piece of evidence, scientists also studied mica in quartz veins. Its age was determined to be 1655 ± 27 million years. This indicates that the shatter cones appeared much earlier, refuting some assumptions that the crater was less than 2.7 billion years old.

The authors of the study conclude that the Miralga structure also known as the North Pole Dome, remains the only reliably confirmed meteorite crater from the Archean Eon. Scientists believe that although many meteorites struck Earth in the past, most of their traces have been completely erased over millions of years by tectonic processes and erosion.