Rocks on Mars may provide link to evidence of living organisms roughly 4 billion years ago

The paper -- by Adrian J. Brown of the SETI Institute and colleagues at NASA's Jet Propulsion Laboratory, Johns Hopkins University Applied Physics Laboratory, the Desert Research Institute and Brazil's Universidade Estadual de Campinas -- analyzes data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), using co-located HiRISE images in order to further characterize the rocks.

The researchers suggest that carbonate bearing rocks found in the Nili Fossae region of Mars are made up of hydrothermally altered ultramafic (perhaps komatiitic) rocks. It also shows that the carbonates at Nili Fossae are not pure Mg-carbonate. Moreover, the study explains that talc is present in close proximity to the carbonate locations -- rather than previously suggested saponite -- and talc-carbonate alteration of high-Mg precursor rocks has taken place.

Brown explains: "We suggest that the associated hydrothermal activity would have provided sufficient energy for biological activity on early Mars at Nili Fossae. Furthermore, in the article we discuss the potential of the Archean volcanics of the East Pilbara region of Western Australia as an analog for the Nochian Nili Fossae on Mars. They indicate that biomarkers or evidence of living organisms, if produced at Nili, could have been preserved, as they have been in the North Pole Dome region of the Pilbara craton."

The discovery, remarked Tilman Spohn, editor of Earth and Planetary Sciences, "marks a significant finding in the Nili Fossae region of Mars, highlighting similarities between traces of life on early Earth and early Mars, and suggests a landing site for an exobiology mission to Mars."