Mascons

Mascons – From the English mass concentration – mass concentration.
Mascons are also called objects located in the lithosphere of the Moon, near its surface, which can cause gravitational fluctuations. As a result of their detection, they were localized due to perturbations in the motion of the Moon’s artificial satellites. Beneath the lunar seas, which have a rounded shape are most often located mascons.
There is an opinion that their origin is connected with the impacts of huge cosmic bodies, which in turn caused in the lunar crust huge, reaching several kilometers, depressions. This was followed by geologic processes. At the bottom, the denser and hotter mantle, which was melted more than the crust, pushed up the bottom of the geologic depression formed by the impact – a depression, forming a lens under it – a bulge consisting of the substance of the mantle that had risen. Part of the mantle substance on the surface rose to the surface in the form of lava and filled the rest of the depression. On this basis, some areas of the lunar crust were found to be more dense than others.
There is a possibility that mascons are present on Mars and Mercury.