The Utopia Basin revisited: Regional slope and shorelines from MOLA profiles

Abstract

MOLA profiles indicate that Utopia Planitia, including the Utopia Basin, has been titled northward by Ο0.025° since formation of the basin but no later than mid-Late Hesperian. This tilt could be a relic of the endogenic formation of the global dichotomy in late Noachian to early Hesperian by a process involving subcrustal erosion in the lowland. The Utopia Basin survives as a deep, circular depression within Utopia Planitia. Along its south flank are several horizontal or near horizontal terraces and benches that may be shorelines of an extensive northern lowland ocean and a more restricted lake within the Utopia Basin. The large size (up to 200 km wide) of these putative shorelines represents a major geomorphic problem to be solved.