Geologic map of the Mare Boreum area of Mars

The Mare Boreum geologic map portrays the north polar are of Mars above lat 65 degrees N. The area contains five physiographic provinces: (1) a residual ice cap characterized by troughs with a counterclockwise outward spiral pattern (Mariner 9 frames DAS 13317550 and DAS 13353320); (2) layered terrain adjacent to the ice cap, exposed within the spiral troughs; (3) a circumpolar band of low-albedo material extending roughly from lat 75 degrees to 82 degrees N.; (4) isolated patches of high-albedo perennial ice near lat 75 degrees N. within a semicircumpolar band between long 120 degrees and 270 degrees; and (5) circumpolar cratered plains of mottled albedo south of lat 75 degrees N.