Wavelet Multi-Scale Analysis of the Linear Gravity Anomalies of the Moon

Abstract

The history of the thermal and dynamic evolution of the Moon is partly recorded by lunar linear structures. Identification and analysis of subsurface linear structures and their associated gravity anomalies provide insights into the early evolution of the Moon. However, the current understanding of their deep extensions is limited. In this study, we employ gravity data and the 2D continuous wavelet transform technique to analyze the subsurface extension of linear structures. Four significant linear gravity anomalies (LGAs) are studied, including the north (FN) and south (FS) anomalies located in the lunar farside and the northwest (NNW) and northeast (NNE) anomalies in the nearside. Our results indicate that the top depths and widths of the mass sources associated with these linear structures can be determined. The intrusion depths of all four LGAs vary along their strike, with the shallowest intrusion depth reaching 8–10 km. For the FN anomaly, the top depths of the intrusive body range from 8 to 20 km, while intrusion widths vary between 30 and 50 km. Wavelet analysis for the FS anomaly indicates an intrusive source with a top width and depth of ∼30 and 10 km. For the NNW anomaly, the source body has top depths of 10–20 km with varying top widths at different sections (25∼50 km). As for the NNE structure, our results suggest substantial top widths between 75 and 150 km alongside relatively shallow top depths of 8–15 km. These LGAs are likely attributed to vertical magma intrusions connected at their bases to the crust-mantle interface.