Variability of spider spatial configuration at the Martian south pole

Jin, Hao; Michael, G.G.; Adeli, Solmaz; Jaumann, R.; Portyankina, Ganna; Hauber, Ernst; Millot, C.; Zuschneid, W.

doi:10.1016/j.pss.2020.104848

Cited by 12 publications

(8 citation statements)

References 88 publications

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“…A review of the observations of these exotic processes can be found in Schmidt and Portyankina (2018). The thickness of the Seasonal South Polar Cap (SSPC) is proposed to be a key factor in controlling the cold‐jetting process (Hao et al., 2020). However, little work has been done so far to investigate the spatio‐temporal variations of the snow/ice level of the SSPC, for example, in the cryptic and non‐cryptic regions (Aharonson et al., 2004; Jian & Ip, 2009; Smith et al., 2001).…”

Section: Introductionmentioning

confidence: 99%

Spatio‐Temporal Level Variations of the Martian Seasonal South Polar Cap From Co‐Registration of MOLA Profiles

et al. 2022

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Each Martian year, approximately 30% of the atmosphere's CO 2 mass is in exchange with the polar surfaces through deposition/sublimation (Leighton & Murray, 1966). The seasonal CO 2 polar caps resulting from repeated depositions of snow/ice can extend down to 50°S/N (Piqueux et al., 2015). Temporal variations of the level and volume of snow/ice associated with the deposition/sublimation process can put crucial constraints on the Mars climate system and volatile circulation models. Additionally, this amount of snow and ice is significant enough to cause seasonal deflection of the lithosphere (Wagner et al., 2022). Constraining the level and mass of the seasonal portion of the polar cap is essential in properly modeling this deflection. Measurements of the level of snow/ice of the seasonal polar caps have been made by the Mars Orbiter Laser Altimeter (MOLA) onboard the Mars Global Surveyor (MGS, Smith et al., 2001;Aharonson et al., 2004;, measuring rock shadow lengths in high-resolution images to deduce the seasonal changes in rock heights on the surface (Mount & Titus, 2015), and precise radiative transfer models using imaging spectroscopy (Andrieu et al., 2018). Compared with the latter two that are spatially and temporally limited due to data availability, MOLA data cover the entire polar regions. Based on profile analysis at different latitudina annuli, Smith et al. ( 2001) measured the maximum seasonal level of snow/ice to be ∼1 m at both poles. In a different approach, Aharonson et al. ( 2004) fitted sinusoidal functions with annual and semi-annual terms to MOLA cross-over height residuals and estimated the maximum level to reach ∼1.5 m at the north pole and ∼2.5 m at the south pole.The "cryptic region" at Martian south pole during the southern spring is roughly located from 50° to 210°E and poleward of 70°S (see also Figure 1 of Hansen et al. (2010)). It is so described as it possesses low temperatures

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Section: Introductionmentioning

confidence: 99%

Spatio‐Temporal Level Variations of the Martian Seasonal South Polar Cap From Co‐Registration of MOLA Profiles

et al. 2022

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“…This is especially the case for the smaller spiders (small R) and for small gas production radii (small r P /R), both of which can be understood as reducing the total area that the pressure is applied to, meaning more gas pressure must be added to achieve the same total stress in the ice. For the densely packed spider separations observed in Hao et al (2019) and Hao et al (2020) and a gas production radius of r P = 0.25R ∼ 6.5 m (even smaller in size than the case simulated by Thomas et al (2011b) above), a total pressure of P crit ≈ 33 kPa can build up before fracturing occurs. Thus, in this case our maximum pressure gradient driving gas flow at the initial breach would be (P crit − P surf )/r P ≈ 33 kPa/6.5 m.…”

Section: Gas Pressurementioning

confidence: 80%

“…that different regolith porosities/permeabilities constrain the gas flow by different amounts, and therefore the radius around each spider where gas can build up. Evidence for the relevance of regolith morphology was observed by Hao et al (2020). These recent results highlight that the potential effectiveness of gas flow through the regolith itself -rather than through a regolith-ice gap -has to be addressed because it seems vital for our understanding of spiders.…”

Section: Introductionmentioning

confidence: 93%

Gas flow in Martian spider formation

Attree,

Kaufmann,

Hagermann

2021

Preprint

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Martian araneiform terrain, located in the Southern polar regions, consists of features with central pits and radial troughs which are thought to be associated with the solid state greenhouse effect under a CO 2 ice sheet. Sublimation at the base of this ice leads to gas buildup, fracturing of the ice and the flow of gas and entrained regolith out of vents and onto the surface. There are two possible pathways for the gas: through the gap between the ice slab and the underlying regolith, as proposed by Kieffer (2007), or through the pores of a permeable regolith layer, which would imply that regolith properties can control the spacing between adjacent spiders, as suggested by Hao et al. (2019). We test this hypothesis quantitatively in order to place constraints on the regolith properties. Based on previously estimated flow rates and thermophysical arguments, we suggest that there is insufficient depth of porous regolith to support the full gas flow through the regolith. By contrast, free gas flow through a regolith-ice gap is capable of supplying the likely flow rates for gap sizes on the order of a centimetre. This size of gap can be opened in the centre of a spider feature by gas pressure bending the overlying ice slab upwards, or by levitating it entirely as suggested in the original Kieffer (2007) model. Our calculations therefore support at least some of the gas flowing through a gap opened between the regolith and ice. Regolith properties most likely still play a role in the evolution of spider morphology, by regolith cohesion controlling the erosion of the central pit and troughs, for example.

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“…Located primarily on the south polar layered deposits and surroundings (Piqueux et al, 2003;Schwamb et al, 2018), these features are characterized by dendritic, tortuous troughs several meters wide and deep which extend from a central pit and range from <50 m to 1 km in diameter (Figure 12d). Their specific morphology types range from `fat' to `starburst' (Hansen et al, 2010) and these sub-types tend to cluster nonrandomly (Hao et al, 2020).…”

Section: Araneiformsmentioning

confidence: 99%

Modern Mars' geomorphological activity, driven by wind, frost, and gravity

et al. 2021

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Extensive evidence of landform-scale martian geomorphic changes has been acquired in the last decade, and the number and range of examples of surface activity have increased as more high-resolution imagery has been acquired. Within the present-day Mars climate, wind and frost/ice are the dominant drivers, resulting in large avalanches of material down icy, rocky, or sandy slopes; sediment transport leading to many scales of aeolian bedforms and erosion; pits of various forms and patterned ground; and substrate material carved out from under subliming ice slabs. Due to the ability to collect correlated observations of surface activity and new landforms with relevant environmental conditions with spacecraft on or around Mars, studies of martian geomorphologic activity are uniquely positioned to directly test surface-atmosphere interaction and landform formation/evolution models outside of Earth. In this paper, we outline currently observed and interpreted surface activity occurring within the modern Mars environment, and tie this activity to wind, seasonal surface CO2 frost/ice, sublimation of subsurface water ice, and/or gravity drivers. Open questions regarding these processes are outlined, and then measurements needed for answering these questions are identified. In the final sections, we discuss how many of these martian processes and landforms may provide useful analogs for conditions and processes active on other planetary surfaces, with an emphasis on those that stretch the bounds of terrestrial-based models or that lack terrestrial analogs. In these ways, modern Mars presents a natural and powerful comparative planetology base case for studies of Solar System surface processes, beyond or instead of Earth.

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Variability of spider spatial configuration at the Martian south pole

Cited by 12 publications

References 88 publications

Spatio‐Temporal Level Variations of the Martian Seasonal South Polar Cap From Co‐Registration of MOLA Profiles

Spatio‐Temporal Level Variations of the Martian Seasonal South Polar Cap From Co‐Registration of MOLA Profiles

Gas flow in Martian spider formation

Modern Mars' geomorphological activity, driven by wind, frost, and gravity

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