They could have contributed to the evolution of the first tectonic phenomena in the planet, according to a study published by the journal Nature Geoscience.
The research, led by Macquarie University in Sydney, Australia, claims that such impacts could have spawned earthquake recycling episodes more than 4 billion years ago. This approach questions the dominant idea so far, which suggests that, in its origins, the Earth had no tectonic activity.
“The interior of the Earth during the Aeonic Eon, between 4.560 and 4 billion years ago, was perhaps too hot to hold tectonic plates, but it is not clear whether large impacts could generate a tectonic system,” the authors explain. Scientists conducted “global-scale tectonic simulations” on the Earth’s evolution exposed to ‘variable impact flows’ during the Haptic era. Although some evidence suggests that there was little activity between the Earth’s crust and the mantle, examination of older geological materials, such as zirconia, points in a different direction.
According to experts, these new tests indicate that a bark recycling process similar to that observed in current subduction zones could occur, where a tectonic plate sinks beneath another. Impacted craters, a more common phenomenon during the formation of our solar system, could have initiated the subduction processes before the appearance of tectonic plates as they are now known, say the authors.
They arrived at this conclusion after analyzing the data provided by a numerical model that simulates the effect of large meteorite impacts on the evolution of tectonic plates on Earth. They also found that the energy released by these impacts warmed the interior of the planet and generated the ascent of columns of materials of the mantle, which, in turn, drives the subduction in the mantle of the thin and fragile plates characteristic of the Earth primitive
Unlike the behavior of the subduction zones located in the limits of current tectonic plates, the simulated subduction events in this study are of short duration (less than ten million years) and are located geographically.
Consequently, the Earth goes from an inactive tectonic state to an active one depending on the size and frequency of the impacts.