Deep groundwater could still be active on Mars and be the origin of surface streams in some near-equatorial areas of the "Red Planet", researchers suggest.
The researchers at University of Southern California (USC) have determined that groundwater likely exists in a broader geographical area than just the poles of Mars and contended that there is an active system, as deep as 750 metres, from which groundwater comes to the surface through cracks in the specific craters they analysed.
The team studied the characteristics of Mars' Recurrent Slope Linea, which are akin to dried, short streams of water that appear on some crater walls on Mars.
Scientists previously thought these features were affiliated with surface water flow or close subsurface water flow, said research scientist Essam Heggy at USC.
The team found similarities between the groundwater moving mechanisms in the Sahara and on Mars.
"Groundwater is strong evidence for the past similarity between Mars and Earth--it suggest they have a similar evolution, to some extent," Heggy said.
He noted that this deep source of groundwater is the most convincing evidence of similarities between the two planets -- it suggest both may have had wet periods long enough to create such an active groundwater system.
"Understanding Mars' evolution is crucial for understanding our own Earth's long-term evolution and groundwater is a key element in this process," Heggy said.
Heggy explained that fractures within some of Mars' craters, enabled water springs to rise up to the surface as a result of pressure deep below. These springs leaked onto the surface, generating the sharp and distinct linear features found on the walls of these craters.
They also provide an explanation on how these water features fluctuate with seasonality on Mars.
The study suggests that groundwater might be deeper than previously thought in areas where such streams are observed on Mars.
For the study, forthcoming in the Nature Geoscience journal, the team used hi-resolution optical images and modelling to study the walls of large impact craters on Mars.