Seamless maps of major elements of the Moon: Results from high-resolution geostationary satellite

TL;DR

This study produces seamless, high-resolution maps of major lunar elements using China's Gaofen-4 satellite data, enhancing geological understanding of the Moon's composition and impact processes.

Contribution

It introduces a method to generate homogeneous lunar element maps from single-exposure satellite images, improving upon previous mosaic and low-resolution data.

Findings

SiO2 and TiO2 dominate mare and highland areas respectively.

Elemental distributions reveal insights into lunar geological processes.

Asymmetric element distribution suggests impact direction at Tycho crater.

Abstract

Major elements such as Fe, Ti, Mg, Al, Ca, and Si play very important roles in understanding the origin and evolution of the Moon. Previous maps of these major elements derived from orbital data are based on mosaic images or low-resolution Gamma ray data. The hue variations and gaps among orbital boundaries in the mosaic images are not conducive to geological studies. This paper aims to produce seamless and homogenous distribution maps of major elements using the single-exposure image of the whole lunar disk obtained by China's high-resolution geostationary satellite, Gaofen-4, with a spatial resolution of ~500 m. The elemental contents of soil samples returned by Apollo and Luna missions were used as ground truth, and were correlated with the reflectance of the sampling sites extracted from Gaofen-4 data. The final distribution maps of these major oxides are generated with the statistical regression model. With these products the average contents and proportions of the major elements for maria and highlands were estimated and compared. The results showed that SiO2 and TiO2 have the highest and lowest fractions in mare and highland areas, respectively. Besides, the relative concentrations of these elements could serve as indicators of geologic processes, e.g., the obviously asymmetric distributions of Al2O3, CaO, and SiO2 around Tycho crater may suggest that Tycho crater was formed by an oblique impact from the southwest direction.