Utopia Basin, Mars: Characterization of topography and morphology and assessment of the origin and evolution of basin internal structure

Abstract

Abstract. Recently obtained Mars Orbiter Laser Altimeter (MOLA) topography has permitted a new assessment of the morphology, structure, and history of Utopia Planitia. The new topographic data convincingly demonstrate that the Utopia region is an impact basin, as originally proposed by McGill [1989], whose major topographic expression is a circular, 1-3 km deep depression •3200 km in diameter. Utopia Basin is the largest easily recognizable impact structure in the northern hemisphere of Mars and is the only portion of the northern lowlands that exhibits a distinct large-scale impact signature; its presence there and its ancient age verify that a significant part of the northern lowlands dates back to the Noachian period. Using slope maps derived from gridded topography, we have mapped a series of linear slope anomalies within the basin and have analyzed their origin. These features can be classified into two groups: one oriented dominantly radial to the basin and the other oriented dominantly circumferential. The circumferential features are tens of kilometers wide and hundreds of kilometers long and appear to remain relatively constant with respect to elevation. We explore end-member hypotheses (1) that the features formed by the direct action of water/ice or (2) that they are tectonic wrinkle ridges. We interpret the majority of these features to be due to tectonic deformation (primarily wrinkle-ridge formation), modified by later sedimentation associated with the emplacement of the outflow channels and the formation of the Vastitas Borealis Formation. On the basis of the characteristics of these features and their association with polygonal terrain, thumbprint terrain, smoothness of units, and evidence of sedimentary deposits, we find that our results support earlier hypotheses proposing that a significant volume of water occupied Utopia Basin during the late Hesperian period of outflow channel formation. Utopia Basin differs significantly in depth and degradation state from the deeper and fresher-appearing Hellas Basin, although the two are both Noachian in age. A significant part of this difference seems reasonably interpreted to be the result of the extensive sedimentary and volcanic infilling history of the northern lowlands.

Episodic flood inundations of the northern plains of Mars

“…Such Noachian/Hesperianaqueous activity is also noted for Gusev impact crater basin where recurrent Ma'adim Vallis flooding may have resulted in episodic lakes Cabrol et al, 1998). In addition, the presence of a significant volume of water in Utopia Basin has been proposed Thomson and Head, 2001), as well as the subsurface outflow and surface runoff from the northwest flanks of the Elysium rise into the Utopia basin (Mouginis-Mark, 1985;Greeley and Guest, 1987;Skinner and Tanaka, 2001) during the Late Hesperian and Amazonian and surface runoff in north Terra Cimmeria from the Late Noachian to Early Amazonian (Nelson et al, 2001). relative age-dated highland and lowland channels to determine their possible contribution to the size and stability of the paleolakes.…”

Possible pingos and a periglacial landscape in northwest Utopia Planitia

“…On Mars, landscapes that include small, elongate to circular mounds hypothesised to be pingos, as well as other possible periglacial features have been identified in three areas: (1) the vast northern plains (Kargel and Costard, 1993;Parker and Banerdt, 1999;Seibert and Kargel, 2001) encompassing Acadilia (Lucchitta, 1981), Chryse (Theilig and Greeley, 1979), Elysium (De Hon, 1997;Rice et al, 2002), and Utopia Planitiae (Tanaka et al, 2000;Seibert and Kargel, 2001; Thomson and Head, 2001); (2) Vastitas Borealis (Greeley and Guest, 1987); and (3) the Gusev crater (Cabrol et al, 1997(Cabrol et al, , 2000Grin and Cabrol, 1998). Water is thought to have played an important role in the landscape evolution of each area.…”

Martian subsurface properties and crater formation processes inferred from fresh impact crater geometries

“…However, unless the olivine-rich unit is much thicker than currently observed, it alone cannot account for the crater observations. In addition, Hesperian volcanic flooding and sedimentary (Vastitas Borealis Formation) deposits and Amazonian volcanic deposits from Elysium form shallow layers within the upper 1 km of the Utopia basin (Thomson and Head 2001). The size range of observed fresh crater forms cannot be controlled by these young surface deposits.…”