A recently published study Nature explores a potentially existing volcanic hotspot beneath an object. The far side of the Moon (the side facing away from Earth) called the Compton-Belkovich Thorium anomaly. Researchers led by the Institute of Planetary Sciences collected data from the hotspot region using microwave devices in the China National Space Administration’s Chang’e-1 and Chang’e-2 orbits. This could help scientists better understand past volcanism in our nearest celestial neighbor, as surface evidence suggests that the moon’s volcanic activity ended 3–4 billion years ago.

What makes this find unique is that the source of the hotspot is not active volcanism such as molten lava, but radioactive elements in now solid rock that was once molten lava billions of years ago. Since granite is the only type of rock that can contain large enough amounts of radioactive elements, this indicates that there was once a large granite magma chamber below the surface of the Moon that fed a smaller surface volcano, similar to how volcanoes on Earth worked.

A senior scientist at the Planetary Science Institute (PSI), Dr. “This means it’s hot below the surface, not on the surface as you see it in infrared,” said Matthew Ziegler. lead author of the study. “The only way to explain this is additional heat from somewhere under the deeper lunar crust. Considered a volcano for this reason, Compton-Belkovich also hides a large source of heat beneath it.

The study calls the Compton-Belkowich feature a lunar granite batholith, which consists of a much larger system about 50 kilometers (31 miles) in diameter, located below the lunar surface, which cooled before erupting. When molten lava cools, it turns into granite, and examples of batholith systems are found beneath volcanic chains on Earth, including the Cascade Mountain Range or the Andes, but they are rarely found throughout the Solar System outside Earth.

Dr. “This was a great project because China, like NASA, released its data, and we were able to work with this unique dataset to find something really interesting about the Moon,” Ziegler said. “According to the rules, we couldn’t work directly with Chinese researchers and all funding came solely from NASA, so we had to follow the navigational steps to open this dataset.”

Dr. Ziegler, co-author of the study, who was a research associate at PSI for his ability to “navigate the data and available literature on this topic” after arriving in the United States on a J visa. He credits Jianqing Fang and “is a great example of what can be done if science and politics work together.” Like Earth, our Moon has a turbulent history of volcanism, but Dr. Ziegler notes that the Apollo missions have shown that this volcanic activity is largely due to impacts, as opposed to traditional volcanism that results from inner planetary processes as seen on Earth.

In addition to the study’s conclusion that this granite hotspot is not the result of active volcanism, its location on the far side of the Moon is also unique. This is because most of the Moon’s volcanism is observed to be on the near side (Earth-facing side), in dark spots, also known as the lunar sea, so the near and far sides are in stark contrast to each other. Lunar mare, which means sea in Latin. Much brighter regions of the lunar surface, consisting of high mountainous regions, are called lunar plateaus. Source