"This scene shows NASA's Curiosity Mars rover at a location called ""Windjana,"" where the rover found rocks containing manganese-oxide minerals, which require abundant water and strongly oxidizing conditions to form. In front of the rover are two holes from the rover's sample-collection drill and several dark-toned features that have been cleared of dust (see inset images). These flat features are erosion-resistant fracture fills containing manganese oxides. The discovery of these materials suggests the Martian atmosphere might once have contained higher abundances of free oxygen than it does now. Credits: NASA/JPL-Caltech/MSSS"
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