Subsurface Habitability Clues in Northern Chryse Planitia, Mars: Implications for Tianwen-3 Landing Site Selection

Abstract

China plans to launch its Tianwen-3 Mars sample return mission in 2028. Within the designated candidate landing zone, this study characterizes a geologically and compositionally diverse region (26°N–30°N, 28°W–36°W) shaped by the interplay of fluvial, periglacial, tectonic, and volatile-related processes. Through integrated geomorphological, mineralogical, and thermophysical analyses, we identify several key features, including widespread olivine exposures within crater floors, walls, and ejecta; conical landforms potentially associated with subsurface sediment mobilization, possibly involving mud-volcanic processes; erosion-resistant mesa units; and polygonal terrains consistent with contractional cracking associated with volatile loss. The spatial arrangement and stratigraphic relationships among coarse-grained residual units, ridge systems, trough networks, and elevated mesas indicate a prolonged and multi-stage geomorphic evolution involving resurfacing, structural deformation, and erosion. Crater size–frequency distribution measurements suggest that a major resurfacing event occurred during the Middle Amazonian, approximately 600–800 million years ago, representing one of the latest resurfacing phases in the region. Collectively, geomorphological, mineralogical, and thermophysical evidence indicates a history of volatile redistribution, structural modification, and subsurface material exposure relevant to understanding the geological evolution and subsurface habitability potential of northern Chryse Planitia. Given its geomorphic diversity, exposed stratigraphy, and evidence of subsurface processes, this region represents a scientifically valuable target for future exploration, including the Tianwen-3 mission.