The 270-kilometer shock crater MFA is the largest on Venus, surrounded by internal and outer rings of molten and frozen rock. Crater appeared, by different estimates, from 300 million to billion years ago. Scientists from Brownovsky university modeled his education in order to better understand the structure of the lithosphere of Venus at that distant time.
Judging by the results obtained, there was no movement of tectonic plates on the next planet. Evan Bjonnes (Evan Bjonnes) and his colleagues are written in an article published in the Nature Astronomy magazine. According to them, the obtained data refute the existing hypotheses that the Venus remains tectonically active until the relatively recently recent time.
On Earth, the testimonics testimonics plates are found everywhere. The subduction zones are known, where one plates are immersed under the other, as well as the mid-ocean ridges, where the formation of a new bark occurs. Orbital apparatus operating in the orbit of Venus, detect similar details and on its surface. However, whether they really have the same origin, figure it is not easy to figure out: a stormy and superlit atmosphere and the Hellic conditions on the surface greatly make it difficult for detailed observations.
Therefore, Bjonns and his colleagues turned to an alternative source of data on the lithosphere of Venus. The ancient shock crater MIC retained two concentric rings along the edge, and their dimensions are determined by the temperature gradient of the cortex. Calculations have shown that at the moment of impact, this gradient was small, that is, with an increase in depth, the temperature rose gradually and not too much.
This, in turn, indicates that Cora Venus was (and perhaps and remains) too thick to split on independently moving plates. "Imagine a freezing reservoir in winter," explains Evan Bjonns. - First, ice appears on the surface, and at the depths are still a little warmer. Gradually, water freezes, and the ice becomes thicker. "
Source: Naked Science