Formation Mechanism of Brightness Temperature Anomaly in CE‐3 Landing Region and Its Significance to Re‐Understand Magmatic Evolution of Mare Imbrium

The discovery of a previously unrecognized mare basalt in the Chang'e‐3 (CE‐3) landing region offers valuable insights for re‐evaluating the evolutionary history of mare basaltic magmatism. This study is the first to use data from the CE‐2 Microwave Radiometer data to systematically analyze the microwave thermophysical properties of the basaltic unit of the CE‐3 landing region by constructing effective brightness temperature (eTB) and brightness temperature difference (TBD) maps and integrating these with chemical element and mineral composition data. Using the random forest algorithm in conjunction with the eTB and TBD data sets, a new geological map is produced. Furthermore, based on the identified age and composition, the correlation between the newly defined basaltic units and their brightness temperature (TB) characteristics was analyzed. The results show that (a) the CE‐3 basaltic unit exhibits a distinct frequency dependent behavior of the TBD, indicating the distinct thermophysical properties of the surface deposits. (b) Mapping further suggests that the CE‐3 basalts may have originated from the Gruithuisen source region in the north‐western part of Mare Imbrium, spanning several basaltic units delineated in previous studies. (c) Correlation coefficients between unit age, composition, and TBD exceeded 0.80, supporting TBD as a robust proxy for basaltic unit characterization. The microwave thermophysical properties provide an effective reference of delineating basaltic units, and their strong correlations with unit age and composition demonstrate the potential of this approach for investigating the magmatic evolution of the Moon.