ZZYZX, CALIFORNIA–Later in the morning the Wooster Geologists visited a favorite location: the Kelso Dunes in the Mojave National Preserve. We arrived before noon so we could work up a hearty appetite for lunch by climbing the dunes first. The Kelso Dunes are made almost entirely of medium to fine sand grains derived from the dry bed of the Mojave River (and ultimately the San Bernardino Mountains where it originates). The most common minerals are clear quartz and white to pink potassium feldspar, with a smaller but prominent component of black magnetite that often concentrates on dune crests (see above). Most of the sand accumulated at the end of the last ice age and has been blowing around in place since then. No new sand is being added to the dunes today. The highest dune rises 200 meters above the valley floor — and it is a hard slog up to the top. (And much faster going down!)
Dune grass baffling sediment and refracting the waveforms of magnetite-rich sand.
