Lunar Mare Ingenii: A comprehensive multi data study unravelling composition, chronology and terrain dynamics

Abstract

The compositional, chronological, topographical, and morphological features of Mare Ingenii, an impact basin situated in the northwest part of the South Pole-Aitken basin (SPA) are cha racterized using different orbital remote sensing data. Examining the chemical characteristics, spectral signatures, age, and surface features help to elucidate the basin's formation process and its volcanic evolution. In the present study, Chandrayaan-1 Moon Minerology Mapper (Ch-1 M³) data is used to prepare Standard Band Ratio (SBR), Optical Maturity (OMAT), 1000 and 2000 nm Integrated Band Depth (IBD) color composite images to map different lithologies and mafic signatures of the basin. Chandrayaan-2 Imaging Infrared Spectrometer (Ch-2 IIRS) data is used to derive 1000 and 2000 nm IBD and result is validated with M³ derived images. Minerals like olivine, pyroxene, plagioclase, spinel, and ilmenite are identified and validated through spectral studies. The FeO wt.% map from Kaguya and the TiO₂ map from the Lunar Reconnaissance Orbiter Camera - Wide Angle Camera (LROC WAC) were used to obtain FeO and TiO₂ abundances. These were then compared with abundances derived from M³ data to validate the compositional analysis. The present study identified 19 mare units in the Ingenii basin using variations in TiO₂, FeO, and IBD color composite maps. Crater Size-Frequency Distribution (CSFD) technique has been employed to obtain the age of each unit and it ranges from 3.8 to 2.3 Ga and the results well correlated with previous studies. It is thus evident that Mare Ingenii has been affected by a prolonged period of mare volcanism along with a few non-mare basaltic surfaces that have been identified, including rille-related lava flows and O'Day impact melt sheets. The basin was flooded mainly by low to very low Ti basalts of the Imbrian period and patches of intermediate Ti basaltic emplacement happened during the Eratosthenian period. The topography of the basin is delineated by using Lunar Orbiter Laser Altimeter (LOLA) data and an outer ring of 600 km is mapped in this study. Morphological features such as rille, wrinkle ridge, graben, swirls, O'Day impact melt, and V-shaped features are identified using Kaguya Terrain Camera (TC) and LROC data which can offer understanding into the basin's past volcanic and cratering process. The results suggest that Mare Ingenii possesses a prolonged volcanic history and the mare is dominated by low to very low Ti basalts sourced from olivine-ilmenite-pyroxene cumulates.