Geology of the Raditladi quadrangle, Mercury (H04)

In this work we present the 1:3,000,000-scale geologic map of the Raditladi quadrangle (H04) of Mercury (22.5-66° N, 90-180° E). The area covers more than 5x106 km2 (nearly 7% of the entire planet) and encompasses several features of interest such as the Caloris basin, the Raditladi basin, hollow clusters and volcanic features. The mapping took advantage of the data produced during MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft (MESSENGER) orbital phase. The mapped deposits include impact-related units observed at several scales from the Caloris basin to the secondary crater chains. The Smooth Plains unit covers the majority of the area, mantling the older Intercrater Plains and Bright Intercrater Plains units. Crater counting achieved on the catalog of craters larger than 10 km produced during mapping, allowed for the definition of the ages of the main units and for the timing of the Caloris impact. Results show that the emplacement of all the main units and the Caloris impact event, representing the main geologic events in the quadrangle, were concentrated between 3.96 and 3.72 Ga. After this intense phase, the geologic framework was modified only by local events like impact craters and hollows formation. We mapped tectonic, cooling-driven and impact-related structures all over the area. This map is among the first products for the detailed geologic characterization of Mercury at such scale. It will contribute as a constraint and a support for both, further local investigation and mapping, and targeting of the forthcoming BepiColombo ESA/JAXA joint exploration mission to Mercury.