Curiosity Rover (IMAGE) DOE/Los Alamos National Laboratory Caption The Curiosity rover examines the Kimberley formation in Gale crater, Mars. 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 that are composed of manganese oxides, which require abundant liquid water and strongly oxidizing conditions to form. The discovery of these materials suggests that the Martian atmosphere might once have contained higher abundances of free oxygen than in the present day. Credit MSSS/JPL/NASA (PIA18390) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.