Evidence of ancient mega-flood found on surface of Mars

3 Mar 2017

Martian-like landscape on the coast of Cyprus. Image: ElenYrebyata/Shutterstock

The ESA has found evidence of a mega-flood of epic proportions that occurred on the surface of Mars billions of years ago.

Mars might be known as the Red Planet with its dry, desert surface, but billions of years ago, the planet looked considerably different.

Two years ago, researchers confirmed the existence of liquid water on the surface of Mars, and, since then, its watery legacy has been gradually uncovered.

New images taken by the European Space Agency (ESA)’s Mars Express spacecraft have revealed a liquid history on Mars that, at one point, culminated with a mega-flood.

Based on photographic analysis, the ESA said that this event occurred between 3.4 and 3.6bn years ago and was so enormous that it extended 3,000km across the planet’s surface.

It is believed to have occurred after a combination of volcanism, tectonics, collapse and subsidence in the Tharsis region of Mars led to several massive groundwater releases from Echus Chasma, which subsequently flooded the Kasei Valles region.

One of the key indicators of the flood was seen in the nearby Worcester Crater (measuring 25km), which was caught up in the brute force.

A colour-coded topographic view shows relative heights and depths of terrain in the region of Mars where Kasei Valles reaches Chryse Planitia. Image: ESA/DLR/FU Berlin

Craters hold the key

While much of the blanket of material surrounding the crater – which was originally thrown out from inside the crater during the impact – has been eroded, the section downstream of the flood has survived.

Analysis showed that over time, the flood gave the crater the appearance of a streamlined island.

Also, the appearance of a stepped topography suggests variations in water levels or even different flood episodes.

However, a nearby crater and its debris blanket remained completely intact, suggesting it occurred after the mega-flood.

Interestingly, this crater’s debris blanket offers evidence for the floodplain, in which the impact occurred, being rich in water or water-ice.

A third crater nearby shows that the impact did not go as deep as its two neighbours, with its central smaller depression suggesting that ice existed beneath its surface when it was created.

All across the vast plateau, small dendritic channels can be seen, which perhaps hints at the varying magnitudes of flooding on multiple occasions.

Colm Gorey was a senior journalist with Silicon Republic