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 amascon (a strong positivegravity 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 exhibitscalloped 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 likepingos 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 ofunderground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water inLake Superior.[18][19][20]
Utopia Planitia Scalloped terrain led to the discovery of a large amount of underground ice enough water to fill Lake Superior[18][19][20]
Martian terrain
Map of terrain
Scalloped topography is common in themid-latitudes of Mars, between 45° and 60° north and south. It is particularly prominent in the region of Utopia Planitia[21][22] in the northern hemisphere and in the region ofPeneus and Amphitrites Patera[23][24] in the southern hemisphere. Such topography consists of shallow, rimless depressions with scalloped edges, commonly referred to as scalloped depressions or simplyscallops. Scalloped depressions can be isolated or clustered and sometimes seem to coalesce. A typical scalloped depression displays a gentle equator-facing slope and a steeper pole-facing scarp. This topographic asymmetry is probably due to differences ininsolation. Scalloped depressions are believed to form from the removal of subsurface material, possibly interstitial ice, bysublimation. This process may still be happening at present.[25]
^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
.jpg)
