China's Mars rover discovers longer water existence on red planet

BEIJING -- By studying the detection data of China's first Mars rover, Zhurong, Chinese geologists have found that the Martian surface had still exhibited significant aqueous activity approximately 750 million years ago.

This discovery shows that water existed on Mars several hundred million years longer than previously thought.

The study, conducted by a research team from the Institute of Geology and Geophysics (IGG) under the Chinese Academy of Sciences and published in the National Science Review, provides new evidence useful for a better understanding of Martian climatic evolution, geological processes and potential habitability.

Zhurong successfully landed in the southern Utopia Planitia on Mars in May 2021. It had traveled 1,921 meters on the red planet by May 2022, collecting abundant scientific data in the process.

Zhurong also conducted a high-frequency quad-polarized ground-penetrating radar survey on Mars, which is akin to performing a detailed CT scan.

Previously, it was widely believed that Mars had entered a global arid phase about 3 billion years ago. However, data from Zhurong reveals that its landing site is extensively covered with a uniform sedimentary layer approximately 4 meters thick underground, beneath which craters are buried.

"The uniform thickness and continuity of the sedimentary rule out the possibility of volcanic eruptions or wind-driven processes. The only reasonable explanation is that this area was in an aqueous sedimentary environment at that time, similar to a shallow sea or a large lake," said Liu Yike, the first author and corresponding author of the study.

Meanwhile, the radar also captured centimeter-scale layered sediments, which formed in a water-based sedimentary environment, further supporting the existence of a shallow aquatic environment in this region in the past.

"Comprehensive analysis indicates that the landing site of Zhurong underwent a significant resurfacing event during the middle-late Amazonian Period, and that sustained aqueous activity still existed on Mars during this period," said Liu.