Martian Araneiforms: A Review

Keown, L. E. Mc; Diniega, S.; Portyankina, Ganna; Hansen, Candice; Aye, K.-M.; Piqueux, S.; Scully, J. E. C.

doi:10.1029/2022je007684

Cited by 6 publications

(3 citation statements)

References 182 publications

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“…This information can also help to determine the current mass balance of the residual north polar cap, that is, whether it is accumulating or ablating. Dynamic geological phenomena formed during sublimation of the SSPC/SNPC, for example, dark fans, polygonal cracks, spiders (south polar region)/furrows (north polar region), and alcoves in the dune fields, can be better modeled and interpreted given meaningful thickness evolution measurements of the overlying seasonal layer (e.g., Dundas et al., 2021; Hansen et al., 2013; Mc Keown et al., 2023; Portyankina et al., 2010; Schmidt & Portyankina, 2018). Meanwhile, the annual growth and retreat of the seasonal deposits are capable of inducing significant elastic displacements of the lithosphere (Métivier et al., 2008).…”

Section: Introductionmentioning

confidence: 99%

Thickness of the Seasonal Deposits at the Martian North Polar Region From Shadow Variations of Fallen Ice Blocks

Xiao,

et al. 2024

JGR Planets

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The seasonal deposition and sublimation of CO2 constitute a major element in the Martian volatile cycle. Here, we propose to use the shadow variations of the ice blocks at the foot of the steep scarps of the North Polar Layered Deposits (NPLD) to infer the vertical evolution of the seasonal deposits. We conduct an experiment at a steep scarp centered at (85.0°N, 151.5°E). We assume that no snowfall remains on top of the selected ice blocks, the frost ice layer is homogeneous around the ice blocks and their surroundings, and no significant moating is present. We show that the average thickness of the seasonal deposits due to snowfalls in Mars Year 31 is 0.97 ± 0.13 m at Ls = 350.7° in late winter. The large depth measured makes us wonder if snowfalls are more frequent and violent than previously thought. Meanwhile, we show that the average frost thickness in Mars Year 31 reaches 0.64 ± 0.18 m at Ls = 350.7° in late winter. Combined, the total thickness of the seasonal cover in Mars Year 31 reaches 1.63 ± 0.22 m at Ls = 350.7° in late winter, continuously decreases to 0.45 ± 0.06 m at Ls = 42.8° in middle spring and 0.06 ± 0.05 m at Ls = 69.6° in late spring. These estimates are up to 0.8 m lower than the existing Mars Orbiter Laser Altimeter results during the spring. Meanwhile, we observe that snow in the very early spring of Mars Year 36 can be 0.36 ± 0.13 m thicker than that in Mars Year 31. This study demonstrates the dynamics of the Martian climate and emphasizes the importance of its long‐term monitoring.

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Section: Introductionmentioning

confidence: 99%

Thickness of the Seasonal Deposits at the Martian North Polar Region From Shadow Variations of Fallen Ice Blocks

Xiao,

et al. 2024

JGR Planets

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“…These information can also help to determine the current mass balance of the residual north polar cap, that is, whether it is accumulating or ablating. Dynamic geological phenomena associated with sublimation of the SSPC/SNPC, for example, dark fans, polygonal cracks, spiders (South Pole)/furrows (North Pole), and alcoves in the dune fields, can be better modeled and interpreted given meaningful thickness evolution measurements of the overlying seasonal layer (for example, Portyankina et al, 2010;Hansen et al, 2013;Schmidt & Portyankina, 2018;Dundas et al, 2021;Mc Keown et al, 2023). Meanwhile, the amount of mass being seasonally added and removed from the surface is enough to induce significant elastic displacements of the lithosphere (Métivier et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Are seasonal deposits in spring at the Martian North Pole much shallower than previously thought?

Xiao,

et al. 2023

Preprint

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The seasonal deposition and sublimation of CO constitute a major element in the Martian volatile cycle. Here, we propose to use the shadow variations of the ice blocks at the foot of the steep scarps of the North Polar Layered Deposits (NPLDs) to infer the vertical evolution of the seasonal deposits at high polar latitudes. We conduct an experiment at a steep scarp centered at (85.0°N, 151.5°E). We show that the average thickness of the seasonal deposits due to snowfalls in Mars Year 31 is 0.97±0.13 m at Ls = 350.7° in late winter, which then gradually decreases in springtime. The large snow depth measured makes us wonder if snowfalls are more frequent and violent than previously thought. Meanwhile, we show that the average frost thickness due to direct condensation in Mars Year 31 reaches 0.64±0.18 m at Ls = 350.7° in late winter and quasi-linearly decreases towards the summer solstice. Combined, the total thickness of the seasonal cover in Mars Year 31 reaches 1.63±0.22 m at Ls = 350.7° in late winter, continuously decreases to 0.45±0.06 m at Ls = 42.8° in middle spring and 0.06±0.05 m at Ls = 69.6° in late spring. These estimates are up to 0.8 m lower than the existing MOLA results during the spring, which can be mainly attributed to MOLA-related biases. In terms of interannual variations, we observe that snow in the very early spring of Mars Year 36 can be 0.36±0.13 m deeper than that in Mars Year 31.

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“…These concepts may have important implications for otherMartian landforms that were originally given a placeholder name, are frequently described as enigmatic, and for which multiple genetic origins are feasible. Although examining the subtleties of each is beyond the scope of this review, interrogating terms such as recurring slope lineae (e.g.,Dundas, 2020) or cryptic terrain and araneiforms (e.g.,McKeown et al, 2023) in the critical framework used here may be worthwhile. Mars has an important historical precedent, now entirely resolved, for a geomorphic problem that was turned into a 'mystery' by the use of induction and the search for universal solutions: the controversy of the existence of canals on the Martian surface.…”

mentioning

confidence: 98%

The fault in our TARs: A critical review of research paradigms for intermediate‐scale bedforms on Mars

Gough,

Barchyn,

Hugenholtz

2023

Earth Surf Processes Landf

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We provide a critical review of research paradigms for classifying intermediate‐scale aeolian bedforms on Mars and the new terminology that has emerged. The systematic classification of bedforms has always been challenging and debated, and no paradigmatic knowledge organization system exists beyond general agreement on the importance of a distinction between ripples and dunes. The diverse aeolian landscapes of Mars have introduced further topics and challenges to these debates. We argue that Martian aeolian geomorphology's knowledge organization system for intermediate‐scale bedforms is preparadigmatic and that consensus over terminology and their definitions has not been established in the literature. A preparadigmatic science can be functional only if scientists operating in the discipline provide precise, falsifiable definitions or use abductive logic. Drawing on evidence and examples from the literature, we argue that the replacement of the conventional abductive paradigm used in bedform classification with inductive logic has created an emerging disciplinary paradigm based on scientific hesitancy and a dependence on complex inductive research structures, epitomized by the concepts of ‘transverse aeolian ridges’ (TARs) and ‘large Martian ripples’ (LMRs). We show that TAR and, increasingly, LMR are inductive constructs that have been popularized despite them causing significant confusion. Notably, we highlight how the terms are irreconcilably used as both a class of bedform and as a non‐genetic placeholder term for bedforms. Suggestions for moving beyond the need for TAR and LMR are provided, focusing on a return to more direct and local hypothesis‐driven research inspired by W.M. Davis's notion of outrageous geological hypotheses. Recent debate surrounding bedforms in Gale crater is presented as an example of the productivity of such an approach, and it is recommended that TAR and LMR no longer be used.

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Martian Araneiforms: A Review

Cited by 6 publications

References 182 publications

Thickness of the Seasonal Deposits at the Martian North Polar Region From Shadow Variations of Fallen Ice Blocks

Thickness of the Seasonal Deposits at the Martian North Polar Region From Shadow Variations of Fallen Ice Blocks

Are seasonal deposits in spring at the Martian North Pole much shallower than previously thought?

The fault in our TARs: A critical review of research paradigms for intermediate‐scale bedforms on Mars

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