Lithospheric Loading Model for Large Impact Basins Where a Mantle Plug Is Present

Abstract

The thin elastic shell lithospheric model is widely used in the geophysical studies of terrestrial bodies (Turcotte et al., 1981). This model assumes that the planetary lithosphere is an elastic shell that deflects when mass-related loads are imposed. The magnitude of deflection depends on the applied loads and the physical properties of the lithosphere (such as elastic thickness). If this deflection causes a change in the relief on a density interface, it will produce a gravity anomaly. Therefore, deflection measurements can be made using gravity and topography data. The elastic thickness can be used to characterize the physical properties of the lithosphere (Watts, 2001), which are mainly influenced by the temperature structure and are therefore closely related to the evolution of the entire planet.The interpretation of gravity and topography data is usually performed in the spherical harmonic (SH) domain. Degree-dependent correlation and admittance (transfer function) between gravity and topography contain information about loads in the lithosphere. Various types of loading models have been proposed. The simplest loading

Lithospheric Elastic Thickness Beneath the Caloris Basin: Implications for the Thermal Structure of Mercury

“…The admittance function calculated using gravity and topography data at the Caloris region is used to infer the elastic thickness ( T e ) by modeling the lithospheric deflection under applied loads. In this work, we adopt a lithospheric loading model incorporated with the mantle plug loading caused by impact process (Deng et al., 2023). This approach is more consistent with the realistic loading scenario than other loading models without initial mantle loading (Belleguic et al., 2005; McGovern et al., 2002).…”

“…We estimate the mantle plug loading by using the crustal thickness model of Mercury (Beuthe et al., 2020b, see below). The inclusion of the initial mantle loading in the lithospheric loading model provides a better fit to the observed admittance at mascons‐related large impact basins on Mars (Deng et al., 2023).…”

“…We first calculate the degree‐dependent gravity‐topography admittance at the Caloris basin region using the localized spectral analysis method (Section 2.2). Then, the flexural lithosphere model (Section 2.3) considering initial mantle plug loading (Deng et al., 2023) is used to fit the modeled admittance to the observed admittance. The elastic thickness ( T e ) and the load ratio ( f ) are estimated through the misfit analysis.…”

The Ancient Lithospheric Parameters of Impact Basins on the Far Side of the Moon Based on the Mantle and Mare Basalt Load Model

“…In this study, we have achieved favorable fitting results by employing a mantle and mare basalt load model, which effectively constrains the lithospheric structure parameters in mare basins (Figures 9, 10, 12, panels (d) and (e)). In contrast, traditional load models have proven inadequate in accurately fitting the theoretical and observational spectra (Deng, Xiao, et al., 2023; Deng, Zhong, et al., 2023; Zhong et al., 2022). Hence, this approach offers a potential solution for future research on determining the structural parameters of the lithosphere in a broader range of mascon basins on the Moon.…”

“…(2023) and Deng, Zhong, et al. (2023) to quantify the model uncertainties as follows: $$$\sigma (Te,f)=\frac{1}{{l}_{\max }-{l}_{\text{win}}+1}{\sum\limits _{l={l}_{\text{win}}}^{{l}_{\max }}\left[\frac{Z(l)-{Z}^{\text{model}}(l)}{\kappa z(l)}\right]}^{2}$$$ where l max represents the highest degree of fit between gravity and topography. Here, the calculated the misfit values of good‐fitted parameters need to be constrained within 1‐𝜎 uncertainty to estimate the range of parameter values.…”