NASA, shows a patch of bright-toned soil so rich in silica

This image released by NASA, shows a patch of bright-toned soil so rich in silica that scientists propose water must have been involved in concentrating it. The silica-rich patch, informally named "Gertrude Weise" was exposed when the Spirit Mars Rover drove over it during the 1,150th Martian day, or sol, of Spirit's Mars surface mission (29 March 2007). One of Spirit's six wheels no longer rotates, so it leaves a deep track as it drags through soil. Scientists have theorized that the patch could have been formed by processes which on Earth establish conditions for microbial life, according to a report from NASA's Pasadena, California Jet Propulsion Laboratory, 12 December 2007. One theory is that the silica, the main ingredient for glass, was produced in a hot spring. The other is that it was generated in a fumarole, where acidic steam seeps through cracks in the planet surface

This image released by NASA, shows the Spirit Mars Rover at the end of its second Martian year. Spirit has discovered a patch of bright-toned soil so rich in silica that scientists propose water must have been involved in concentrating it. The silica-rich patch, informally named "Gertrude Weise" was exposed when drove over it during the 1,150th Martian day, or sol, of Spirit's Mars surface mission (29 March 2007). Scientists have theorized that the patch could have been formed by processes which on Earth establish conditions for microbial life, according to a report from NASA's Pasadena, California Jet Propulsion Laboratory, 12 December 2007. One theory is that the silica, the main ingredient for glass, was produced in a hot spring. The other is that it was generated in a fumarole, where acidic steam seeps through cracks in the planet surface.