"Not only was water active in this region to weather the rocks, but there was enough of it to run through the beds, transport the clays and run into the lake and form the delta, " said Ms Ehlmann.

BBC: Water 'widespread' on early Mars

In a separate study published in the journal Nature Geoscience, a team led by Bethany Ehlmann, from Brown University, analysed sedimentary deposits in two deltas within Mars' Jezero crater - which once hosted a body of water measuring some 40km (25 miles) across.

BBC: Water 'widespread' on early Mars