Astronomers have found new evidence that the moon can still be tectonically active. This is a network of young ridges on the visible side of the Moon, which, according to scientists, is a kind of echo of the cataclysm that spawned the South Pole-Aitken basin several billion years ago. The article was published in the journal Geology.
It is known that the Moon was geologically active several billion years ago, but there is evidence of continued to this day small tectonic activity on the Earth’s natural satellite, which is caused by global compression of the bowels due to the cooling of the Moon and tidal forces from the Earth.
Seismographs of US Apollo manned missions from 1969 to 1977 recorded 28 seismic oscillation events, eight of which could actually be generated by fault movements as mechanical stress in the lunar crust increased. In other studies, based on images obtained by lunar orbiting vehicles, it is shown that narrow ridges observed on the moon in many places and ledges crossing small craters speak of tectonic processes that took place less than a hundred million years ago.
Adomas Valantinas from the University of Bern and Peter Schultz from Brown University searched the region for regolith-free areas on the Moon using images taken with the NAC camera of the Lunar Reconnaissance Orbiter, as well as data on satellite surface temperature obtained by the on-board radiometer Diviner. They found more than five hundred areas with open bedrock on the ridges, as well as narrow (about thirty meters) ledges and grabens .
The absence of small craters in these areas indicates geologically young areas (less than ten million years), which form faster than collapse as a result of meteorite bombardment. Many of these ridge systems are far beyond the masonry in the lunar seas and are not associated with any global tectonic pattern.
Scientists suggest that the discovered systems of ridges are still being formed, and the process itself was launched during the collision of the Moon with a large body several billion years ago, which led to the formation of the South Pole – Aitken basin , considered one of the largest impact craters in the Solar System.
The data from GRAIL probes speak in favor of this – in 2014, it discovered a network of cracks in the Moon’s crust, through which in the past magma flowed to the surface of the Moon. The ridge network spatially correlates with these ancient deep dykes. Perhaps the “moonquakes” recorded by the Apollon seismographs are also associated with the consequences of the cataclysm that generated the South Pole – Aitken basin.
Astronomers believe that in order to fully understand the current seismic activity of the Moon and the processes occurring in its interior, it is necessary to deploy a global geophysical network of sensors on the surface of the Earth’s satellite .