ABSTRACT
New spectral data from the OMEGA visible and near-infrared imaging spectrometer on the Mars Express spacecraft reveal widespread occurrence of gypsum-rich dunes in the North Polar region of Mars. Dunes appear to have undergone complex chemical and physical evolution; the source area for gypsum, however, has not yet been determined. Martian gypsum-rich dunes are located near the North Polar cap, a plausible Martian water-source. The close proximity to the meltwater channels of the North Polar cap suggests that the gypsum supply might have been controlled by water-involved processes similar to those on Earth.

On Earth, gypsum dunes are rare and restricted to semi-arid areas where older sulfate-rich sedimentary rocks undergo dissolution by meteoric waters on/near the surface. The White Sands gypsum dunes are the largest known aeolian sulfate-rich deposits on Earth and are an excellent natural laboratory for studying the origins of sulfate dunes. In particular, this communication focuses on the interaction between hydrology and climate that lead to the deposition of the source sediment for the dunes and controls the current dune field morphology.

In 2007, sulfur stable isotope methods were used at White Sands area to determine the source of the original dune sediments, document the involvement of water in their deposition, and to trace the connection of these sediments to the current dune field. Variation of d34 S values indicates that White Sands dunes formation appears to be linked to a specific time period characterized by a distinct climatic and/or tectonic regime during the Holocene. Similar morphological features observed between White Sands dunes and those on Mars might provide new insights regarding the climate history of polar processes on Mars that led to development of gypsum-rich eolian system