Clay mineralogy reveals new clues about Mars’ past habitability

Washington: Researchers have said that the first detailed examination of clay mineralogy in its original setting on Mars is offering new insights on the planet`s past habitability.

The research was led by Planetary Science Institute Senior Scientist David T. Vaniman. The sedimentary rock samples tested were collected by NASA`s Mars Science Laboratory rover Curiosity at Yellowknife Bay in Gale Crater on Mars. The rover`s Chemistry and Mineralogy X-Ray Diffraction and Fluorescence (CheMin XRD/XRF) instrument analyzed the samples. Vaniman said that the in situ X-ray diffraction results reveal the presence of smectite, a type of clay mineral typical of soils and sediments that have not been deeply buried, heated, or otherwise altered, asserting that the X-ray diffraction data are also important for what they do not detect-clay minerals like chlorite or illite that would have formed in strongly alkaline or hydrothermal fluids. Vaniman`s paper discusses that this is the first analysis of a complete mineral assemblage in a Martian sediment, accounting for all of the associated debris that settled into a lake as well as minerals formed in the lake and after it dried out. He said that unlike the sediments that the Mars Exploration Rover Odyssey has found at Meridiani Planum, the Gale Crater mudstone lacks iron sulfates that indicate an acidic environment, explaining that the only sulfates found in the mudstone are calcium sulfates, associated with veins that formed after the lake was gone and not indicative of an acidic system. Vaniman added that the mudstone mineralogy is consistent with a geochemically benign and potentially habitable environment. The study has been published in Science magazine.