Research press release


Nature Geoscience

Ancient acidic waters on Mars


J Burowitzraらは、オポチュニティー探査車により得られたデータを用いて、岩石の堆積をもたらした可能性のある地球化学的過程について評価した。彼らの地球化学的計算は、鉄に富んだ中性の地下水が地表に到達すると、紫外線の放射、あるいは大気中の酸素にさらされることにより、鉄はすぐに酸化されることを示している。


The acidic surface waters that once bathed Meridiani Planum on Mars could have been generated by interactions between groundwater and the early martian atmosphere, according to a paper published online this week in Nature Geoscience. Meridiani Planum, visited by the NASA rover Opportunity, is host to a number of rock formations thought to be formed in acidic water.

Joel Hurowitz and colleagues used data obtained by Opportunity to assess the geochemical pathways that could have led to the formation of the rocks. Their geochemical calculations showed that as iron-rich, fairly neutral groundwater reached the surface, the iron could have been rapidly oxidized by exposure to ultraviolet radiation or atmospheric oxygen. The resulting chemical reactions would have acidified the water remaining on the surface.

The team suggests that the prevalence of the acidic surface water was a consequence of the martian climate drying.

doi: 10.1038/ngeo831


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