Fresh evidence for groundwater on Mars

Researchers have found fresh evidence of the presence of groundwater on Mars.
Investigators note that such conditions in a similar Earth environment would have been conducive for microbial colonisation.
Researchers investigated the Equatorial Layered Deposits (ELDs) of Arabia Terra in Firsoff crater area on Mars to understand their formation and potential habitability.
On the plateau, ELDs consist of rare mounds, flat-lying deposits, and cross-bedded dune fields.
Monica Pondrelli from the International Research School of Planetary Sciences, Italy and colleagues interpret the mounds as smaller spring deposits, the flat-lying deposits as playa, and the cross-bedded dune fields as aeolian.
They note that groundwater fluctuations appear to be the major factor controlling ELD deposition.

Pondrelli and colleagues also note that the ELDs inside the craters would likely have originated by fluid upwelling through the fissure ridges and the mounds, and that lead to evaporite precipitation.

The presence of spring and playa deposits points to the possible presence of a hydrological cycle, driving groundwater upwelling on Mars at surface temperatures above freezing.
As a basis for their research, Pondrelli and colleagues produced a detailed geological map of the Firsoff crater area.
The new map includes crater count dating, a survey of the stratigraphic relations, and analysis of the depositional geometries and compositional constraints.
They note that this ELD unit consists of sulfates and shows other characteristics typical of evaporites such as polygonal pattern and indications of dissolution.