Catharcheus (Gadey, Prearchean)

Main article: The history of the Earth before the appearance of hominids

4.42 billion hp: Collision of the Earth with the cosmic body, the formation of the Moon and a strong change in the inclination of the Earth's axis

Simulations show that 4.42 billion years ago, our planet collided with another cosmic body, which led to the formation of the moon, and it was this event that could change the slope of the axis of rotation of the Earth. Geological data confirm that the Earth for a long time, until about 600 million years ago, had a much larger slope.

4.2 billion hp: Silica-rich Felzic rocks emerged during the bombing of the Earth with asteroids

The oldest rocks ever found on Earth  probably formed during the asteroid bombing, Australian scientists said in August 2018. Numerous "accidents" occurred more than four billion years ago.

About three decades ago, scientists discovered  ancient felsic rocks rich in silica near the Acasta River in Canada. These are the oldest rocks on Earth, 4.2 billion years old. In other words, they were formed about 600 million years after the formation of the Earth and before the emergence of life.

The finds contain a unique mixture of chemical elements (compared  to similar rocks that formed much later). Researchers have suggested that the oldest objects appeared thanks to some other geological processes.

Dr. Tim Johnson  and colleagues from the University of Painting (Australia) modeled the likely conditions under which such breeds could form. They  concluded that their formation could be facilitated by partial "melting" of the earth's surface at temperatures ranging from 800 to 900 degrees Celsius at very low pressure.

As Johnson says, on a young Earth , such high temperatures could not occur without assistance. In his opinion, the late heavy bombardment, the period of intense impact of asteroids on Earth ( and not only) played a role here.

"We are aware that the Earth was bombed for 600-700 million years after formation. The fact that we know about the only felsite rocks over four billion years old instantly made me think that such effects could be the reason for their appearance , "says the scientist

Thanks to such intense "rain" from asteroids, rocks like those found in Canada could be quite common at the  time, Johnson believes.

Nevertheless  , the plate tectonics that took place later "drowned" most of them in the earth's bowels. In other words, such breeds may be the only "survivors" of events that occurred at the beginning of Earth's history.

 In the future, Johnson hopes to explore Siberia to find more geological evidence to support his idea. The results of the study are presented in the scientific publication Nature Geoscience^[1].

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