Heat Production Rate of Lunar Major Basins: New Insights Into Lunar Thermal Evolution

The heat production of radioactive elements drives the thermal evolution of the Moon, and the heat production rate (HPR) based on Th, K, and U elements is also a crucial parameter constituting the current lunar heat flow. Exploring the distribution and source of HPR on the lunar surface can furnish evidence for the analysis of the Moon’s evolutionary history and thermochemical structure, while the distinctive HPR states of the lunar basins that have undergone complex geological activities can provide more evolutionary information. Consequently, the data of heat producing elements in the gamma-ray spectrum of Chang’e-2 (CE-2) were inverted, and the HPR distribution status in lunar major basins, South Pole-Aitken (SPA), Smythii, Nubium, Humorum, Cognitum, Nectaris, Serenitatis, Crisium, Imbrium, and Orientale, was calculated and analyzed to reveal the causes of HPR anomalies and better describe the evolutionary history of lunar materials. There are three main sources of high HPR materials in lunar basins based on their HPR distribution patterns: 1) ejecta excavated by large-scale impact events; 2) magma with high HPR materials produced by volcanic activity within the basin itself; and 3) the high HPR materials carried to the lunar surface by the volcanic activity of Procellarum KREEP Terrane (PKT) and then transported and deposited into the surrounding basins. In addition, the distribution of high HPR materials in the lunar crust and asthenosphere is extremely uneven across the entire Moon, and they originate from different source than the Fe-Ti-rich magmas.