Timing of smooth-topped Chaotic Terrain formation in southern circum-Chryse, Mars

Abstract

The presence of large outflow channels on Mars underscores the planet's dynamic hydrologic history. Chaotic terrain has been identified as the source regions for the floodwaters responsible for carving these channels, however they remain enigmatic due to unresolved questions regarding the mechanisms of water expulsion and the evolution of terrain deformation. Utilizing the latest CTX, HRSC, and MOLA datasets alongside Digital Elevation Models (DEM) and Triangulated Irregular Networks (TIN), we examined smooth-topped chaotic terrain including Hydraotes Chaos, a crater pair in Hydaspis Chaos, Baetis Chaos, and Candor Chaos, all located south of Chryse Planitia. Our findings indicate that the collapse of these chaotic terrain is predominantly controlled by local processes rather than by regional influences. Furthermore, the evidence supports the conclusion that the largest chaotic terrain can proceed by multiple mechanisms and is not solely reliant on heat sources such as crustal heating or local volcanism and that their formation spanned from the Middle Noachian to the Late Hesperian/Early Amazonian. These results refine our understanding of Martian surface processes by emphasizing the significance of localized geological conditions in chaotic terrain evolution. Large areas of broken up 'chaotic terrain' are thought to be the source regions for some of the floodwaters responsible for carving large channels on the surface of Mars. In this study we use orbital images to create 3D models of the surface of 4 chaotic terrain locations in and around Valles Marineris, Mars. Our findings suggest that the chaotic terrain are formed by local mechanisms, rather than being controlled by regional-scale tectonics. In addition, the largest chaotic areas did not need extra heat from external sources to trigger their collapse, and they formed over a much longer time span than previously thought. This work helps clarify how local conditions influenced the evolution of Mars' surface.