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The veins in Yellowknife Bay are a hydraded calcium sulfate

The veins in Yellowknife Bay are a hydraded calcium sulfate
The veins in Yellowknife Bay are a hydraded calcium sulfate ChemCam views of light-toned veins in rocks in the "Yellowknife Bay" area of Mars together with analyses of their composition. The top image, taken sol 125 (December 13, 2012), shows a close-up of the rock named "Crest." The middle image, taken sol 135 (December 23, 2012), shows a close-up of the rock named "Rapitan." The spectral profile of Crest's light-colored vein is shown in red and Rapitan's in blue, while that of a basaltic calibration target of known composition is shown in black. These results suggest the veins are unlike typical basaltic material. They are depleted in silica and composed of a calcium-bearing mineral. Fainter emission lines, shown in the bottom graphs, identify the presence of sulfur and hydrogen. Scientists interpret these results to mean Crest and Rapitan's light-colored veins contain hydrated calcium sulfates. These minerals could be gypsum or bassanite. On Earth, calcium sulfates like gypsum form frequently in veins when relatively dilute fluid circulates at low to moderate temperatures. The ChemCam analysis helped Curiosity mission managers decide where to use the rover's drill for the first time. NASA / JPL / LANL / CNES / IRAP / LPGN / CNRS