Sand grains of the Summit - Sol 607

A basic tenet of Sedimentology is that the farther a piece of rock travels from its source, the smaller and rounder in shape it becomes as the materials suffer impacts with other grains during transport by wind or water. Grains that have not traveled as far are more angular and less rounded. A comparison of frames taken by the MI on Spirit suggests that sand that has accumulated in drifts on the plains of Gusev Crater traveled farther from the source rock than similar sand grains in the hills inside Gusev. In a MI frame taken on the plains of Gusev Crater (see PIA05288), sand deposits were made up of rounded grains, in contrast with this recent image of a sand drift near the top of Husband Hill that shows poorly sorted, more angular grains of sand (...). The photo covers an area 3 cm across. The scale of the image (31 microns/pixel) allows features as small as 0,1 mm to be resolved.

N.B.: sono nelle ultime 2 righe i "Dati Contingenti" sui MI frames che la NASA non fornisce (praticamente) MAI...