Lunar barren

Lunar barren is a type of terrain.

Description
The surface of the Moon has been subject to billions of years of collisions with both small and large asteroidal and cometary materials. Over time, these impact processes have pulverized and "gardened" the surface materials, forming a fine grained layer termed "regolith."

The thickness of the regolith varies between two meters beneath the younger maria, to up to 20 meters beneath the oldest surfaces of the lunar highlands. The regolith is predominantly composed of materials found in the region, but also contains traces of materials ejected by distant impact craters.

The term "mega-regolith" is often used to describe the heavily fractured bedrock directly beneath the near-surface regolith layer. The regolith contains rocks, fragments of minerals from the original bedrock, and glassy particles formed during the impacts. In most of the lunar regolith, half of the particles are made of mineral fragments fused by the glassy particles; these objects are called agglutinates.

The chemical composition of the regolith varies according to its location; the regolith in the highlands is rich in aluminium and silica, just as the rocks in those regions. The regolith in the maria is rich in magnesium and is silica-poor, as the basaltic rocks from which it is formed.

The lunar regolith is very important because it also stores information about the history of the Sun. The atoms that compose the solar wind - mostly helium, neon, carbon, and nitrogen - hit the lunar surface and insert themselves into the mineral grains. Upon analysing the composition of the regolith, particularly its isotopic composition, it is possible to determine if the activity of the Sun has changed with time. The gases of the solar wind could be useful for future lunar bases, since oxygen, hydrogen (water), carbon and nitrogen are not only essential to sustain life, but also are potentially very useful in the production of fuel. The composition of the lunar regolith can also be used to infer its source origin.