This image shows Opportunity exploring the layered rocks on the inner wall of Endurance Crater (Image: NASA/JPL-Caltech/Cornell)



What is responsible for the sulphate sediments detected on Mars by NASA’s Opportunity rover? Unlike Earth it’s not standing water. Volcanism or meteorite impacts could be responsible for the sedimentation. Two separate studies have led to this conclusion. This finding bolstered the idea that Mars has been dry for most of its history. It seems life may have had a difficult time getting started on the planet.



The rover Opportunity was misled by the sedimentary, layered rock rich in sulphate salts and riddled with small spheres of haematite, nicknamed “blueberries”, that they were formed by substantial amounts of acidic, salty water. Expected to form in salty pools, the rover failed to find high concentrations of other elements, such as magnesium, iron and calcium.



This led the researchers to seek out alternative explanations for the sulphates at Meridiani. And now, this led two groups to proposing “dry” scenarios on the Red Planet in separate studies in the journal Nature.



Via: New Scientist