WUHAN, May 19 (Xinhua) -- Chinese researchers have discovered direct evidence that proves the existence of an ancient ocean on the northern plain of Mars, according to the China University of Geosciences, Wuhan.

Previous studies found evidence of a large amount of liquid on early Mars, but the claims have remained controversial due to the lack of in situ analysis.

A research team led by Xiao Long, professor from the university, analyzed the scientific data from the multispectral camera of Mars rover Zhurong, and has for the first time found petrological evidence of marine sedimentary rocks on the surface of Mars, according to a research article published in the journal National Science Review.

"When we looked at the images from the rover's on-board camera, we discovered that the bedding structures of exposed rocks are significantly different from the common volcanic rocks on the surface of Mars as well as the bedding structures formed by aeolian sands," Xiao said.

He added that the bidirectional flow characteristics indicated by the bedding knowledge were consistent with the low energy tidal flows in the Earth's shore-shallow ocean environment.

The results of the study have provided direct support for the existence of an ancient ocean on Mars.