Scientists have made an exciting discovery below the surface of the Moon—a massive Granite formation. This granite is believed to have formed billions of years ago when molten lava from ancient lunar volcanoes cooled down. The team, led by Matthew Siegler, used special microwave frequency data to measure the heat beneath a suspected volcanic feature called Compton-Belkovich. By analyzing the data, they found that the heat source came from a concentration of radioactive elements unique to the Moon, indicating the presence of granite.
In the past, scientists believed that the Moon's craters were created by volcanoes. However, studies conducted during the Apollo missions in the 1950s revealed that most craters were actually formed by impacts from other celestial bodies. But now, a new instrument has provided evidence of volcanic activity on the Moon.
Using a special instrument that examines microwave wavelengths (longer than infrared), researchers were able to map the temperatures beneath the Moon's surface. One particular suspected volcano, called Compton-Belkovich, stood out by emitting strong microwave signals. This indicated that there was a significant heat source beneath the surface, suggesting that the volcano was not entirely dormant.
Surface evidence suggests that this volcano last erupted around 3.5 billion years ago, meaning the heat does not originate from molten lava. Instead, it comes from the presence of radioactive elements within the solid rock. The only type of rock known to contain sufficient amounts of these elements is granite. Therefore, the data collected by this innovative microwave instrument reveals that a large Moon volcano was once fed by an even larger granite magma chamber beneath it, making it the most Earth-like volcanic activity found on the Moon.
Lunar Granite
Granite is a type of rock that forms beneath extinct volcanoes and is often found on Earth. It is created when lava cools without erupting, leaving behind a large formation called a batholith. Batholiths are even bigger than the volcanoes they fed, just like the Sierra Nevada mountains in the western United States.
The lunar batholith discovered by the scientists is located in a volcanic region of the Moon and is surprisingly large, estimated to have a diameter of 50 kilometers. While granite is relatively common on Earth, it is extremely rare on the Moon because the Moon lacks the water and plate tectonics processes that contribute to granite formation.
The researchers had the unique opportunity to work with publicly available data from Chinese missions, in addition to NASA's data. Due to limitations, they were unable to directly collaborate with Chinese researchers and received funding exclusively from NASA. However, they managed to extract valuable insights from the data, thanks to the expertise of Jianqing Fang, who navigated the information and existing literature. This project serves as an excellent example of the potential when science and politics collaborate successfully.
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Reference : A Research Article by Matthew A.Siegler and his team, Published in Nature (2023).
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