Geologic map of the Mare Boreum area of Mars
The Mare Boreum geologic map portrays the north polar area of Mars above lat 65 ˚ N. T he 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 ˚ to 82 ˚ N; (4) isolated patches of high-albedo perennial ice near lat 75 ˚ N . within a semicircumpolar band between long 120 ˚ and 270 ˚ ; and (5) circumpolar cratered plains of mottled albedo south of lat 75 ˚ .
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