^1,2Kewei Shen, ¹Panming Xue, ¹Duojun Wang, ¹Rui Zhang, ²Guangchao Chen, ¹Kexuan Zhang, ¹Liang Wei
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2026.117132]
¹High Pressure Experiment Science Center, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
²College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, China
Copyright Elsevier

The Moon shows marked differences in geophysical and geological properties between its nearside and farside, long attributed to internal thermal state. However, the present-day lunar thermal gradient remains poorly constrained. In this study, we measured the thermal conductivity and diffusivity of lunar mantle olivine under 0.5–4.0 GPa and 298–1273 K, demonstrating that lattice conduction was the dominant heat transport mechanism. Combining with regional variation parameters including crustal thickness, radiogenic heat production, and modeled surface heat flow, we constructed thermal profiles for distinct lunar regions. Our results revealed a significant nearside-farside thermal asymmetry, with temperature differences reaching ~79–180 K at depth. Elevated nearside mantle temperatures suggested that partial melting may still persist at depths greater than ~700 km. This localized partial melting likely contributes to the observed low seismic velocity and high electrical conductivity anomalies, as well as the occurrence of deep moonquakes beneath the nearside.