Correlations between magnetic anomalies and surface geology antipodal to lunar impact basins

Abstract

Previous work has shown that the strongest concentrations of lunar crustal magnetic anomalies are located antipodal to four large, similarly aged impact basins (Orientale, Serenitatis, Imbrium, and Crisium). Here, we report results of a correlation study between magnetic anomaly clusters and geology in areas antipodal to Imbrium, Orientale, and Crisium. Unusual geologic terranes, interpreted to be of seismic or ejecta origin associated with the antipodal basins, have been mapped antipodal to both Orientale and Imbrium. All three antipode regions have many high-albedo swirl markings. Results indicate that both of the unusual antipode terranes and Mare Ingenii (antipodal to Imbrium) show a correlation with high-magnitude crustal magnetic anomalies. A statistical correlation between all geologic units and regions of medium to high magnetization when high-albedo features are present (antipodal to Orientale) may suggest a deep, possibly seismic origin to the anomalies. However, previous studies have provided strong evidence that basin ejecta units are the most likely sources of lunar crustal anomalies, and there is currently insufficient evidence to differentiate between an ejecta or seismic origin for the antipodal anomalies. Results indicate a strong correlation between the high-albedo markings and regions of high magnetization for the Imbrium, Orientale, and Crisium antipodes. Combined with growing evidence for an Imbrian age to the magnetic anomalies, this supports a solar wind deflection origin for the lunar swirls.