Geology of the Borealis quadrangle (H01), Mercury

We present the first complete geological map of the Borealis quadrangle (H01), Mercury’s north polar region. H01 spans latitudes 65°N to 90°N and longitudes 0°–360°, covering an area just over 3.5 million km2, approximately 4.7% of the planet’s surface. Map digitisation was conducted at scales between 1:300,000 and 1:700,000, with final presentation at 1:3,000,000, using end-of-mission data products from NASA’s MESSENGER mission. We distinguish three principal photogeologic plains units: intercrater plains, intermediate plains, and smooth plains. All craters ≥20 km in diameter and associated materials were mapped and classified by degradation state. Two versions of the map have been completed, using three-class and five-class respectively. Surficial units and areas of permanent shadow that house radar bright deposits in craters ≥5 km in diameter (poleward of 80°N) have been digitised. This map provides geological context for data to be collected by ESA-JAXA’s BepiColombo mission.