What’s So Special About Large Grains on Mars?

Most recently, Perseverance performed an abrasion named Ouzel Falls, pictured above. Slightly obscured by shadow from the rover in this image, this abrasion patch is exciting because of the large grains seen in and around the abrasion patch. Larger grains are good targets for exploring elemental and mineral composition with PIXL and SHERLOC because these instruments can collect multiple analysis points on each large grain. Compositional information of the grains from these instruments can show if the grains are polymineralic or monomineralic. Grains that are determined to be polymineralic, or those that are made up of multiple minerals, can provide important information about the geology and composition of their source terrains. Furthermore, larger grains that are polymineralic could preserve minerals that may not have survived transport as individual grains due to being too small or susceptible to weathering, so this abrasion patch could contain minerals that we haven’t seen before.