Geologists found the oldest impact crater on Earth — they became the structure Yarrabubba located in Australia. It turned out that the age of the shock structure is 2229 million years, more than 200 million years of age more of other known craters on Earth. Article published in the journal Nature.
It is believed that bombardment of Earth by small bodies have played an important role in its evolution. However, data on such disasters are fragmented, mainly due to the movement of tectonic plates and erosion, which gradually destroy impact craters. The oldest evidence of impact events on the Earth are Archean and Paleoproterozoic sediments that were discovered in Kaapvaal craton in southern Africa and the Pilbara craton in Western Australia, covering the period from 3470 to 2460 million years ago; however, the crater was not there.
Up to this time had known only two precisely dated impact structures of Precambrian age. This is the dome of Vredefort with a diameter of more than 250 kilometers, which was formed 2023 ± 4 million years ago, and the crater Sudbury larger than 200 kilometers in the Canada. Other possible impact structures dated to the Paleoproterozoic period, or are inaccurate of a certain age, or debate about their impact origin.
Structure Yarrabubba is a shock pool, located within Yilgarn craton in Western Australia. In this region, not a round crater; however, the magnetic anomaly with a diameter of about 20 kilometers is interpreted as a remnant of the Central uplift of an impact crater with an initial diameter of 70 kilometers. Yarrabubba is one of the oldest impact craters on Earth, but for a long time scientists could not determine the exact age.
A group of researchers led by Timmons Erickson (Erickson Timmons) reports the results of the Dating of samples of minerals of zircon and monazite, found in the crater, which was subjected to recrystallization shock from impact. To determine the age of rocks used uranium-lead method. It turned out that the age of the shock structure is 2229 ± 5 million years, over 200 million years of age more of other known craters on Earth. This makes Yarrabubba the oldest of them.