Modern water at low latitudes on Mars: Potential evidence from dune surfaces

• DOI: 10.1126/sciadv.add8868
• Publication Date: 2023-04-28T17:58:20Z
• Authors: Xiaoguang Qin; Xin Ren; Xu Wang; Jianjun Liu; Haibin Wu; Xingguo Zeng; Yong Sun; Zhaopeng Chen; Shihao Zhang; Yizhong Zhang; Wangli Chen; Bin Liu; Dawei Liu; Lin Guo; Kangkang Li; Xiangzhao Zeng; Hai Huang; Qing Zhang; Songzheng Yu; Chunlai Li; Zhengtang Guo
• Keywords: Earth, Environmental, Ecological, and Space Sciences; 13. Climate action

Landforms on the Martian surface are critical to understanding the nature of surface processes in the recent past. However, modern hydroclimatic conditions on Mars remain enigmatic, as explanations for the formation of observed landforms are ambiguous. We report crusts, cracks, aggregates, and bright polygonal ridges on the surfaces of hydrated salt-rich dunes of southern Utopia Planitia (~25°N) from in situ exploration by the Zhurong rover. These surface features were inferred to form after 1.4 to 0.4 million years ago. Wind and CO 2 frost processes can be ruled out as potential mechanisms. Instead, involvement of saline water from thawed frost/snow is the most likely cause. This discovery sheds light on more humid conditions of the modern Martian climate and provides critical clues to future exploration missions searching for signs of extant life, particularly at low latitudes with comparatively warmer, more amenable surface temperatures.