Microwave frequency data collected from a lunar orbiter has revealed the presence of a deposit of cooled magma beneath a volcano on the Moon called Compton-Belkovich. This discovery, made by a team of scientists led by Matthew Siegler, has challenged existing theories about the formation of the lunar crust.
The scientists used the microwave frequency data to measure the heat below the surface of the suspected volcanic feature and determined that it was coming from a concentration of radioactive elements found in granite. This finding suggests that the large granite formation discovered beneath the Moon’s surface was formed from the cooling of molten lava that fed a volcano or volcanoes that erupted approximately 3.5 billion years ago.
Granites are typically associated with water and plate tectonics, raising questions about past conditions on the Moon. The presence of granite on the Moon is quite rare, as the Moon lacks the water and plate tectonic processes typically involved in its formation on Earth.
Siegler explained that granites are remnants of the plumbing systems below extinct volcanoes, with the granite formation left when lava cools without erupting known as a batholith. The lunar batholith discovered by the scientists has an estimated diameter of 50 kilometers, surprising researchers with its size.
The discovery of this granite body helps to explain how the early lunar crust formed. Siegler and his team are now questioning whether there was water on the Moon, at least in this particular spot, or if the extreme heat alone was responsible for the formation of the granite.
The research team obtained the data for their study from two Chinese lunar orbiters, Chang’E-1 and Chang’E-2, using four-channel microwave radiometer instruments. The data was publicly released by the Chinese space agency and made available for analysis.
The findings of this study have been published in the journal Nature and will be presented by Siegler at the upcoming Goldschmidt Conference in Lyon, France. The research was funded through NASA’s Lunar Data Analysis Program and work related to the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer.