17:15 〜 19:15
[PPS09-P16] Exploring Potential Aquatic Environments in Mid-to-High Latitudes on Mars Based on Evaporative Landforms in the US
キーワード：火星、地球アナログ、ポリゴン、乾燥収縮ポリゴン、塩湖ポリゴン、ハビタブル環境
The presence of liquid environments on present-day Mars is an important question in planetary science. In low-latitude regions, recurring slope lineae (RSL) are marked as possible evidence of transient liquid environments (McEwen et al., 2011). However, despite theoretical and observational evidence suggesting that liquid environments could exist mid-to-high latitudes remain less studied compared to equatorial regions. Features such as polygonal terrains (El-Maarry et al., 2014), similar to those in terrestrial salt lakes may indicate past or present aquatic environments. Observations from the Phoenix Mars Lander, including temperature and humidity measurements and the detection of perchlorates, suggest that stable liquid brines could persist near the surface even in cold high-latitude environments (Rivera-Valentin et al.,2020).
This study aims to investigate the formation and characteristics of polygonal terrains on Mars by comparing them with desiccation polygons in terrestrial analog environments. To achieve this, we conducted field investigations in the southwestern United States using drone surveys, digital elevation models (DEM), Sentinel and ASTER data, and distribution mapping to analyze polygon formation processes and their relationship with environmental factors. Additionally, we used HiRISE images of Mars' northern mid-to-high latitudes (40°N–60°N) to map polygonal landforms similar to the desiccation polygons identified in the United States.
In the US, we identified 3 types of polygons: Raised rim polygons (~15 m; having wavy raised edges), Sinuous Depression polygons (~50 m; having raised rim polygon in pit-like structures on the boundary), and Low rim polygons (30~50 m; having sunken sharp boundaries). Sentinel imagery of three of these types coexisting revealed that Raised rim and Sinuous Depression polygons are currently interacting with surface water, whereas Low Rim polygons have remained dry for at least the past five years, suggesting that they are relict features. ASTER analysis showed high concentrations of halite and gypsum in polygons interacting with surface water, indicating that salt accumulation influences their development. Carbonate is also distributed in the low rim polygon area. This suggests that Raised rim polygons and Sinuous Depression polygons formed through liquid evaporation, providing potential evidence of recent aquatic environments, while Low rim polygons may reflect past aquatic environments.
Our preliminary analysis on Mars reveals that Raised Rim polygons are primarily distributed at latitudes above 60°N, while Low rim polygons and an intermediate type are found between 40°N and 60°N. These findings suggest that evaporative processes may be occurring in Martian mid-to-high latitudes, where perchlorate-rich environments could support transient liquid brines. Understanding these landforms enhances our knowledge of Mars' hydrological history and has significant implications for future exploration and astrobiology.
This study aims to investigate the formation and characteristics of polygonal terrains on Mars by comparing them with desiccation polygons in terrestrial analog environments. To achieve this, we conducted field investigations in the southwestern United States using drone surveys, digital elevation models (DEM), Sentinel and ASTER data, and distribution mapping to analyze polygon formation processes and their relationship with environmental factors. Additionally, we used HiRISE images of Mars' northern mid-to-high latitudes (40°N–60°N) to map polygonal landforms similar to the desiccation polygons identified in the United States.
In the US, we identified 3 types of polygons: Raised rim polygons (~15 m; having wavy raised edges), Sinuous Depression polygons (~50 m; having raised rim polygon in pit-like structures on the boundary), and Low rim polygons (30~50 m; having sunken sharp boundaries). Sentinel imagery of three of these types coexisting revealed that Raised rim and Sinuous Depression polygons are currently interacting with surface water, whereas Low Rim polygons have remained dry for at least the past five years, suggesting that they are relict features. ASTER analysis showed high concentrations of halite and gypsum in polygons interacting with surface water, indicating that salt accumulation influences their development. Carbonate is also distributed in the low rim polygon area. This suggests that Raised rim polygons and Sinuous Depression polygons formed through liquid evaporation, providing potential evidence of recent aquatic environments, while Low rim polygons may reflect past aquatic environments.
Our preliminary analysis on Mars reveals that Raised Rim polygons are primarily distributed at latitudes above 60°N, while Low rim polygons and an intermediate type are found between 40°N and 60°N. These findings suggest that evaporative processes may be occurring in Martian mid-to-high latitudes, where perchlorate-rich environments could support transient liquid brines. Understanding these landforms enhances our knowledge of Mars' hydrological history and has significant implications for future exploration and astrobiology.