Crustal Thickness of the Moon: Implications for Farside Basin Structures and Thermal History

Abstract

We compute lunar crustal thickness using the latest SELENE gravity and topography data. For gravity, our model is the first model incorporating direct farside tracking by Kaguya/SELENE gravity-mapping mission resulting in an improved gravity field model over the farside. For topography, our model is the first global (including polar regions) topography based on laser altimetry. These data enable us to reduce the truncation and filtering of higher degrees and they allow a more realistic estimation of the lunar crustal thickness variations. Using the newly developed our lunar crustal thickness model, we discuss characteristics of the farside basin structures such as type I and type II basins [Namiki et al., 2009]. We also discuss the causes of the difference between type I and type II basins, that were not discussed by Namiki et al. [2009]. Our model suggests that the differences of type I and type II basins are probably due to difference of the ratio between the pre-impact crustal thickness (Moho depth) and impact scale.