Physical and chemical weathering

Although Viking Lander data suggest oxidized, palagonite-like weathering rinds on some rocks and bulk surface sediments possibly composed of clay-salt mixtures, studies of Martian weathering have remained largely theoretical with few observational constraints. Physical weathering may have included rock splitting through growth of ice, salt or secondary silicate crystals in voids. Chemical weathering probably involved reactions of minerals with water, oxygen and carbon dioxide although predicted products vary sensitively with the abundance and physical form postulated for the water. -from Authors