Ancient Mars supported liquid water

Rodiano Bonacci
Settembre 19, 2017

As we know, the red planet is completely filled with surprises, so researchers are completely dedicated to unveiling its hidden secrets. Now they have discovered something that strengthens their claim of the habitability of Mars in ancient times.

"Deposition occurred during the Hesperian (3.7 to 3 billion years ago), with current surfaces exposed via erosion during the Hesperian through the early Amazonian (2.5 billion years ago)". A region on the red planet named Aeolis Dorsa contains some of the most spectacular and densely packed river deposits on Mars, said the study.

These deposits are observable with satellite images because they have undergone a process called "topographic inversion", where the deposits filling once topographically low river channels have been exhumed in such a way that they now exist as ridges at the surface of the planet, they said.

Using high-resolution images from the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) instruments onboard NASA's Mars Reconnaissance Orbiter and topographic data from the Mars Orbiting Laser Altimeter (MOLA) onboard NASA's Mars Global Surveyor, they identified river deposit stacking patterns and changes in sedimentation styles controlled by a migratory coastline. Also, they figured out the river-paleo transport direction for a subset of those ridges.

These measurements when put together demonstrated that the studied river deposits once filled incised valleys. In our planet, the incised valleys are generally cut and filled during rising and falling of sea level and according to the researchers similar type of rising and falling water levels inside a large water body might have resulted in the formation of paleo-valleys in the fluvial deposits area.

Researchers said that cross-cutting relationships were observed at the valley-scale, which hinted about the multiple episodes of water level rise and fall, each of them well over 50 meters, which is considered similar to that of the eustatic sea level changes on the Earth.

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