Other geological features, such as deltas and alluvial fans preserved in craters, also argue very strongly for warmer, wetter conditions at some interval or intervals in earlier Mars history.[70] Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is also independent mineralogical, sedimentological and geomorphological evidence.[71] Some authors have even gone so far as to argue that at times in the Martian past, much of the low northern plains of the planet were covered with a true ocean hundreds of meters deep, though this remains controversial.[72]
Composition of "Yellowknife Bay" rocks – rock veins are higher in calcium and sulfur than "Portage" soil – APXS results – Curiosity rover (March, 2013).
Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water.[73] Some of the evidence believed to indicate ancient water basins and flows has been negated by higher resolution studies by the Mars Reconnaissance Orbiter.[74] In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, which demonstrates that water once existed on Mars.[75] More recent evidence for liquid water comes from the finding of the mineral gypsum on the surface by NASA's Mars rover Opportunity in December 2011.[76][77] Additionally, the study leader Francis McCubbin, a planetary scientist at the University of New Mexico in Albuquerque looking at hydroxals in crystalline minerals from Mars states the amount of water in the upper mantle of Mars is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200 to 1000 meters.[78]
On March 18, 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock.[79][80][81] Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 cm, in the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain
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Composition of "Yellowknife Bay" rocks – rock veins are higher in calcium and sulfur than "Portage" soil – APXS results – Curiosity rover (March, 2013).
Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water.[73] Some of the evidence believed to indicate ancient water basins and flows has been negated by higher resolution studies by the Mars Reconnaissance Orbiter.[74] In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, which demonstrates that water once existed on Mars.[75] More recent evidence for liquid water comes from the finding of the mineral gypsum on the surface by NASA's Mars rover Opportunity in December 2011.[76][77] Additionally, the study leader Francis McCubbin, a planetary scientist at the University of New Mexico in Albuquerque looking at hydroxals in crystalline minerals from Mars states the amount of water in the upper mantle of Mars is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200 to 1000 meters.[78]
On March 18, 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock.[79][80][81] Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 cm, in the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain
