With the help of data and photos from NASA’s Lunar Reconnaissance Orbiter (LRO), scientists discovered now-dead silicate volcanoes. According to primary author Brad Jolliff of Washington University most of the volcanic activity on the moon was basaltic. Because the moon’s rotation has been affected by tidal forces between the Earth and the moon, only one side of the moon is visible from the Earth. Due to the characteristics of the material of the moon fractionate, this volcano cools, due to large seas which are on the near side and having a high content of thorium, a radioactive element (increased, in this case means a few tens of parts per million).
To find out what time this volcanoes were formed , scientists began to count the craters that were formed over time. They said that the oldest crater is 800 million years since the foundation, and the youngest is 200 million years and younger. At the present time «Lunar Reconnaissance Orbiter» continues to scan a lot of other areas of the Moon, so there is a chance that there will be more senior in age craters.