Several impact craters on Mars are proposed to have been ancient lakes and represent potential targets for future exploration. Analysis of the mineral deposits preserved in two craters show that they probably were not lakes after all.
In a paper to be highlighted by Nature Geoscience, Ted Roush, along with colleagues Giuseppe Marzo, Sergio Fonti, Vincenzo Orofino, Armando Blanco, Christoph Gross, and Lorenz Wendt, used data acquired by the Mars Reconnaissance Orbiter to analyze the spectra of mineral deposits in the Luqa and Cankuzo craters on Mars. Although both craters were found to contain deposits of sheet-like silicate minerals indicative of past water activity – the minerals were found in only patchy exposures or confined to isolated layers in the crater walls. If the minerals had formed in a lake, the distribution of the deposits within the craters should have been more uniform.
They conclude that the silicate minerals did not form within a standing body of water but instead probably formed during short-lived, episodic flow of underground water that was mobilized by the impact events.
More details can be found in the manuscript entitled Assessing spectral evidence of aqueous activity in two putative martian paleolakes that will appear in the journal Icarus,