The Utopia basin is estimated to have formed around 4.3-4.1 billion years ago.[6][7] The impactor was likely around 400–700 kilometres (250–430 mi) in diameter.[8][9][10] The basin was subsequently mostly filled in, resulting in a mascon (a strong positive gravity anomaly) detectable by orbiting satellites.[11][12]
Many rocks at Utopia Planitia appear perched, as if wind removed much of the soil at their bases.[13][14] A hard surface crust is formed by solutions of minerals moving up through soil and evaporating at the surface.[15] Some areas of the surface exhibit scalloped topography, a surface that looks like it was carved out by an ice cream scoop. This surface is thought to have formed by the degradation of an ice-rich permafrost.[16] Many features that look like pingos on the Earth are found in Utopia Planitia (~35–50° N; ~80–115° E).[17]
On November 22, 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.[18][19][20]
^ abMcGill, G. E. (1989-03-10). "Buried topography of Utopia, Mars: Persistence of a giant impact depression". Journal of Geophysical Research. 94: 2753–2759. Bibcode:1989JGR....94.2753M. doi:10.1029/JB094iB03p02753.
^Mutch, T. et al. 1976. "The Surface of Mars: The View from the Viking 2 Lander". Science: 194. 1277–1283.
^Hartmann, W. 2003. A Traveler's Guide to Mars. Workman Publishing. New York.
^Arvidson, R. A. Binder, and K. Jones. 1976. "The Surface of Mars". Scientific American: 238. 76–89.
^Sejourne, A. et al. 2012. Evidence of an eolian ice-rich and stratified permafrost in Utopia Planitia, Mars. Icarus. 60:248–254.
^Soare, E., et al. 2019.
Possible (closed system) pingo and ice-wedge/thermokarst complexes at the mid latitudes of Utopia Planitia, Mars. Icarus. doi:10.1016/j.icarus.2019.03.010
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