A large formation of granite discovered below the lunar surface likely was formed from the cooling of molten lava that fed a volcano or volcanoes that erupted early in the Moon’s history – as long as 3.5 billion years ago.
A team of scientists led by Matthew Siegler, an SMU research professor and research scientist with the Planetary Science Institute, has published a study in Nature that used microwave frequency data to measure heat below the surface of a suspected volcanic feature on the Moon known as Compton-Belkovich. The team used the data to determine that the heat being generated below the surface is coming from a concentration of radioactive elements that can only exist on the Moon as granite.
Granites are the igneous rock remnants of the plumbing systems below extinct volcanos. The granite formation left when lava cools without erupting is known as a batholith.