Morphological study of landforms in the Northern Polar Region of Mars

2020 ◽  
Author(s):  
Marina Sánchez-Bayton ◽  
Erwan Treguier ◽  
Miguel Herraiz ◽  
Patrick Martin ◽  
Akos Kereszturi ◽  
...  
Keyword(s):  
Polar Region ◽  
A Priori ◽  
Medium Size ◽  
Polar Cap ◽  
Geophysical Research ◽  
Water Ice ◽  
Irregular Structures ◽  
Volcanic Processes ◽  
Glacial Processes ◽  
North Polar

<p>Abstract</p> <p>This work focuses on the study of the characteristics and possible origin of distinct positive topographic landforms located in Scandia Cavi and Olympia Undae [1]. These are two regions close to the northern polar cap of Mars and which are of special interest because of the potential joint presence of volcanism, glacial processes and gypsum deposits which could be related to the past presence of liquid water there. Such processes can cast light on the geological evolution of the area.</p> <p>We use images from Mars Express and Mars Reconnaissance Orbiter, as well as MOLA topographic profiles from Mars Global Surveyor to investigate 201 small and medium-size landforms in these two regions. These landforms have a priori similar characteristics, such as similar sizes and forms, but their origin might not be the same. A detailed analysis of images and morphometric parameters has allowed their classification into 6 groups, which are the so-called cratered cones, impact craters, ambiguous craters, simple and peaked domes, and irregular structures.</p> <p>Different possible origins for these landforms are discussed such as impact, aeolian, glacial and volcanic processes. The possible implications for relationships between an available volcanic heat source nearby water ice and gypsum deposits make the area particularly interesting toward further constraining the region’s geology.</p> <p> </p> <p>References</p> <p>[1] Sánchez-Bayton et al., Morphological analyses of small and medium size landforms in Scandia Cavi and Olympia Undae, North Polar Region of Mars, under review at Journal of Geophysical Research: Planets</p> <p> </p>

scholarly journals Avalanches of the martian north polar cap

2020 ◽  
Author(s):  
Patricio Becerra ◽  
Susan Conway ◽  
Nicholas Thomas ◽  
Keyword(s):  
Polar Regions ◽  
Martian Surface ◽  
Polar Cap ◽  
Water Ice ◽  
The North ◽  
Imaging Science ◽  
Resolution Imaging ◽  
North Polar ◽  
Gas Expansion ◽  
Trigger Mechanisms

<p>In 2008, the High Resolution Imaging Science Experiment (HiRISE) on board NASA’s MRO fortuitously captured several discrete clouds of material in the process of cascading down a steep scarp of the water-ice-rich north polar layered deposits (NPLD). The events were only seen during a period of ~4 weeks, near the onset of martian northern spring in 2008, when the seasonal cover of CO2 is beginning to sublimate from the north polar regions. Russell et al. [1] analyzed the morphology of the clouds, inferring that the particles involved were mechanically analogous to terrestrial “dry, loose snow or dust”, so that the events were similar to terrestrial “powder avalanches” [2]. HiRISE confirmed the seasonality of avalanche occurrence the following spring, and continued to capture between 30 and 50 avalanches per season (fig. 1b,c) between 2008 and 2019, for a total of 7 Mars Years (MY29–MY35) of continuous scarp monitoring.</p><p>In this work we will present statistics on these events, in an attempt to quantify their effect on the mass balance of the NPLD, and with respect to competing processes such as viscous deformation and stress-induced block falls that do not trigger avalanches [3,4]. We also use a 1D thermal model [5] to investigate the sources and trigger mechanisms of these events. The model tracks the accumulation and ablation of seasonal CO2 frost on a martian surface. Russell et al. [1] support an initiation through gas-expansion related to the presence of CO2 frost on the scarp. Therefore the amount of frost that lingers on different sections of the model scarp at the observed time of the avalanches will provide evidence either for or against this particular mechanism. We will present preliminary results and discuss their implications.</p><p>References: [1] P. Russell et al. (2008) Geophys. Res. Lett. 35, L23204. [2] D. McClung, P.A. Schaerer (2006), Mountaineers, Seattle Wash. [3] Sori, M. M., et al., Geophys. Res. Lett., 43. [4] Byrne et al. (2016), 6th Int. Conf. Mars Polar Sci. Exploration [4] C. M. Dundas and S. Byrne (2010) Icarus 206, 716.</p>

scholarly journals Climate-driven deposition of water ice and the formation of mounds in craters in Mars’ north polar region

Icarus ◽  
2012 ◽  
Vol 220 (1) ◽  
pp. 174-193 ◽  
Author(s):  
Susan J. Conway ◽  
Niels Hovius ◽  
Talfan Barnie ◽  
Jonathan Besserer ◽  
Stéphane Le Mouélic ◽  
...  
Keyword(s):  
Polar Region ◽  
Water Ice ◽  
North Polar

Water-ice clouds and dust in the north polar region of Mars using MGS TES data

2008 ◽  
Vol 56 (2) ◽  
pp. 227-245 ◽  
Author(s):  
L.K. Tamppari ◽  
M.D. Smith ◽  
D.S. Bass ◽  
A.S. Hale
Keyword(s):  
Polar Region ◽  
Ice Clouds ◽  
Water Ice ◽  
The North ◽  
North Polar

Morphometry and temperature of small sub-10 km craters at Mercury’s northern pole: Implications for source and stability of water ice

2020 ◽  
Author(s):  
Hannah Susorney ◽  
Carolyn Ernst ◽  
Nancy Chabot
Keyword(s):  
Polar Region ◽  
Thermal Conditions ◽  
Diameter Ratio ◽  
Clear Correlation ◽  
Polar Regions ◽  
Thermal Models ◽  
Water Ice ◽  
The North ◽  
North Polar ◽  
Stability Of Water

<p>Mercury’s polar regions host deposits of radar-bright material in regions of permanent shadow, commonly the interior of impact craters, and the deposits are hypothesised to be water ice (i.e., Chabot et al., 2018). Thermal modelling, prior to the arrival of the MESSENGER mission, found that water ice is not thermally stable in craters smaller than 10 km, assuming the craters had a depth-to-diameter ratio of 0.2 (Vasavada et al., 1999). Studies of the distribution of radar-bright deposits have identified deposits in craters under 10 km (Deutsch, et al., 2016). In this study, we used the high-resolution north polar topography from the MESSENGER mission to evaluate the morphometry and temperatures of craters with diameters of 5-10 km to explore if these craters could host stable water ice on geologic timescales.</p> <p>We measured the depth and diameter of 201 5-10 km in diameter craters between 75-85° N. MLA tracks that bisected the crater were used to measure the depth and diameter of 99 craters, spanning all longitudes of this north polar region. Thermal models for the north polar region of Mercury use the gridded MLA topography sampled at 1 km resolution (Paige et al., 2013; Chabot et al., 2018), so it was important to ensure the gridded topography accurately captured the craters’ shapes before using the results of these thermal models for these small craters, Comparisons between the MLA track profiles and the profiles taken through the gridded MLA product showed consistent depth to diameter profiles in both datasets, substantiating the use of the gridded MLA product to be used to determine depth and diameter values for these craters and the thermal models for these craters to be used to explore the stability of water ice in these craters.</p> <p>The average depth-to-diameter ratio of the 201 craters is 0.15, 25% lower than the estimate used in pre-MESSENGER thermal study (Vasavada et al., 1999). Thermal measurements of the 156 craters show that many of them have average temperatures below 110 K, meaning that they have thermal conditions that would allow water ice to be stable on geologic timescales under a thin layer of insulating material. Only three craters had small, single-pixel regions with maximum temperatures under 110 K, suggesting that water ice is not stable on the surface in the majority of small craters, except for isolated regions or below the 1-km scale of the thermal model. These results show that water ice would be stable in simple, sub-10 km diameter craters on Mercury and that the presence of radar-bright deposits in these craters is not a constraint on the age of radar-bright deposits.</p> <p>However, our mapping results do show a clear correlation with radar-bright signatures and longitude. In particular, around 60°E longitude, we observe a higher percentage of radar-bright craters. One of Mercury’s two cold poles is nearby at 90°E, but a large complex crater, Prokofiev-112 km in diameter, is also located at 64°E and many of the craters that are radar-bright appear to be secondaries of Prokofiev. Possible explanations for this longitude distribution are being actively investigated, including association with Prokofiev, cold-pole thermal conditions, effects of radar visibility, and the potential for uneven water ice distribution in the small craters near Mercury’s north pole.  </p>

scholarly journals Relationship between topography and flow in the north polar cap on Mars

2003 ◽  
Vol 37 ◽  
pp. 363-369 ◽  
Author(s):  
Christine Schøtt Hvidberg
Keyword(s):  
Temperature Effects ◽  
Flow Model ◽  
Formation Mechanisms ◽  
Flowing Water ◽  
Polar Cap ◽  
Ice Flow ◽  
Water Ice ◽  
The North ◽  
North Polar ◽  
The Relationship

AbstractAssuming that the permanent north polar cap of Mars consists of flowing water ice, the relationship between topography and flow is examined along a profile extending from the pole in the 160° E direction This profile is intersected by scarps and troughs that are characteristic of the north polar cap The flow is calculated by a finite-element ice-flow model which includes divergence of the flow, longitudinal stresses and temperature effects. Ice-flow velocities are generally on the order of 0.1–1 mm a–1 but are enhanced at scarps and troughs to cm a–1. Ice flow smooths out the troughs. Troughs affect the flow to the bottom of the cap. Beneath a trough, ice is dragged upward. Longitudinal stresses are able to drag the lowest part of the ice past smaller troughs. At the pole-facing side of major troughs, ice is stagnant or flows slowly poleward. Implications for formation mechanisms of scarps and troughs are discussed.

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