Optimized inversion of Chang’e-2 gamma-ray spectrum data into heat production rate for thermal evolution study: Imbrium Basin as an example

Abstract

The lunar surface element distribution obtained from Chang’e-2 gamma-ray spectrometer has provided new insights into the thermal activity and element migration of the Moon. To further investigate lunar thermal evolution and geological activities, the heat production rate (HPR) distribution was selected as a breakthrough. An optimized inversion method for Chang’e-2 gamma-ray spectrum data, based on multivariate statistical analysis, was developed to effectively reduce the influence of time-varying factors by improving the background estimation and subtraction process. The results validated the utility of HPR for lunar research. The global HPR distribution maps not only provide a reference for assessing the thermal state of the lunar surface, demonstrating that radiogenic heat production can be reliably studied at a global scale, but also enable detailed investigations of regional geological processes. In the Imbrium Basin, HPR clearly reflects the effects of large-scale impact events and subsequent mare volcanic activity. High-HPR materials associated with impact ejecta can be distinguished from the lower-HPR mare basalts. Furthermore, by integrating HPR data with additional geological information, it is possible to assess and partially subdivide the structure of the Imbrium Basin, providing new quantitative insights into its evolution and compositional heterogeneity.

Keywords

Chang’e-2 gamma-ray spectrum / Heat production rate / Heat producing elements / Mare Imbrium / Background subtraction / Thermal evolution

CRediT authorship contribution statement

Zhenghe Li: Writing - original draft, Visualization, Software, Formal analysis, Data curation. Yuyan Zhao: Writing - original draft, Resources, Project administration, Investigation, Funding acquisition. Xiaodan Tang: Writing - review & editing, Validation, Supervision, Methodology, Conceptualization. Zhiguo Meng: Formal analysis, Data curation.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the National Key Research and Development Program of China (2021YFA0715104).

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.gsf.2026.102254.

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