Chinese rover Zhurong might have found the coastline of the ancient northern ocean of Mars

sarahjay1 (69)memberin Popular STEM • last year

Planetary scientists from the China University of Geosciences have found direct evidence of the presence of a water ocean in the northern lowlands of Mars about 3.3 billion years ago.

This, according to the scientists, is indicated by the sedimentary deposits found by the Zhurong rover.

By now, it is known that in the distant past, rivers flowed and lakes existed on Mars.

An ocean probably occupied the northern lowlands of Mars during the Noachian (4.1–3.7 billion years ago) and Hesperian (3.7–3 billion years ago) periods.

However, for a long time there were disputes about where the boundary of its coastline passed, since observational data from the surface of Mars were not enough.

Also, the interpretation of the information already collected was complicated by traces of other volcanic and glacial processes.

Now a team led by Long Xiao of the School of Earth Sciences said they had direct evidence that an ocean actually existed in the northern hemisphere of Mars.

We are talking about several boulders and rocks studied using the Zhurong rover in the Great Northern Plain, in a region that was previously interpreted as a possible long coastline.

It was believed that it could have formed in the late Hesperian period and consists of sedimentary deposits that arose due to the flow of water from rivers and canals, as well as groundwater into the ocean.

The rocks discovered by Zhuzhong range in size from a few centimeters to several tens of centimeters and have not been greatly altered by wind erosion.

They demonstrate parallel-lamellar bedding with local lenticular formations, as well as sedimentary structures with a predominance of transverse-layered, less often lenticular and scaly layers.

(IGGCAS https://bit.ly/3BRENAQ)

Bedding and small-scale channel structures are also observed.

The scientists concluded that the bidirectional orientation of currents, which can explain the observed thicknesses of sedimentary layers, their direction and grain size in them.

This is not typical for rivers, but for shallow marine environments.

The rocks found by the rover must have been formed during the drying and retreat of the ocean during the Hesperian period, which confirms its existence in the past.

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