A concept that has emerged in recent years is that there are distinct sand transport pathways in the Mojave Desert, where eolian sand is moved between basins (see figure below).

Part of this model is that sand dunes near Parker, Arizona, east of the Colorado River, may be the endpoint for one of these sand transport pathways.

If this hypothesis is true, then it has important implications for Colorado River history. It means that there has been a period(s) in the past when the Colorado River was completely dry; otherwise, sand transport by wind across the river valley could not take place.

The hypothesis can be tested by comparing the composition of the Parker dunes with: (1) dunes in California that are upwind along the sand transport pathway and (2) Colorado River sediments. Colorado River sediments in this area are quartz-rich and K-feldspar-poor and therefore have low K, Rb, and Ba contents.

Parker, Arizona dunes have compositions that are very close to Colorado River sediments and much different from dunes in the Mojave Desert of California (see figure above). Therefore, it can be concluded that this dune field has a different origin from those in the Mojave, and is derived from Colorado River sediments, similar to the Algodones dunes. The sand transport pathway model may be partially correct for the Mojave Desert, but does not extend across the Colorado River.