Possible ice-wedge polygonisation in Utopia Planitia, Mars and its latitudinal gradient of distribution

• Published in: Icarus
• Main Authors: Soare, R. J., Conway, S.J., Williams, J.-P., Philippe, Meven, Keown, L.E. Mc, Mc Keown, L, Godin, E., Hawkswell, J.
• Other Authors: Dawson College, Laboratoire de Planétologie et Géodynamique UMR 6112 (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Space Science (ESS-UCLA), University of California Los Angeles (UCLA), University of California-University of California, The Natural History Museum London (NHM), Université Laval Québec (ULaval), ANR-19-CE01-0010,Permolards,Les molards, marqueurs de l'évolution de la dégradation du pergélisol de montagne(2019)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Mars; climate; surface; atmosphere; [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Arctic; Ice; permafrost; Thermokarst; wedge*
• Online Access: https://hal.archives-ouvertes.fr/hal-03008487; https://hal.archives-ouvertes.fr/hal-03008487v2/document; https://hal.archives-ouvertes.fr/hal-03008487v2/file/LCP-HCP_2nd%20revision_FORHAL_all.pdf; https://doi.org/10.1016/j.icarus.2020.114208

International audience On Earth, ice complexes are commonplace landscapes amidst the continuous permafrost of coastal or near-coastal plains in the Arctic. Formed by the freeze-thaw cycling of water, ice complex features include: hummocky (thermokarstic) terrain, inflated or deflated by the presence of absence of excess ice; thermokarst lakes (i.e. excess ice that has thawed and pooled); alases (i.e. thermokarst basins emptied of water); and, ice-wedge polygons, often characterized by raised (ice-aggraded) or lowered (ice-degraded) margins relative to the polygon centres.The origin and development of these complexes is rooted in inter-or intra-glacial pulses of temperature that engender widespread thaw, meltwater distribution and migration through the soil column (sometimes to decametres of depth), and the freeze-thaw cycling of the meltwater.The possible existence of ice-rich terrain on Mars revised by the freeze-thaw cycling of water dates back to the grainy Mariner-mission photographs of the 1960s and 1970s. However, absent of regolith samples from areas where this terrain is hypothesised, attempts to validate the ice-rich hypothesis often have ended abruptly, either with spectrometric inferences of water-equivalent hydrogen to one metre or so of depth or with “looks-like”, therefore “must-be” analogies derived of Earth-based ice-complexes.In the case of small-sized Martian polygons with low- and high-centres, the similarities of form between ice and sand-wedge polygons on Earth has equivocated the reach of ice-wedge hypotheses on Mars.Here, we show that:1) The plains' terrain of our study region in Utopia Planitia (40-50o N; 100-125o E) displays a statistically-significant and positive (linear) correlation between the ratio of low-centred to high-centred polygons (lcps vs hcps) and a poleward latitude of distribution.2) This linear correlation would be expected, in as much as ground-ice stability increases with latitude, were the shoulders of higher-latitude lcps underlain by (aggraded) ice-wedges and ...