Sedimentary structure of large sand dunes: examples from Dumont and Eureka dunes, California

S U M M A R Y The current research presents ground penetrating radar images up to 30m in depth of two large desert dunes in California, USA— a barchanoid ridge in the Dumont field and a linear dune in the Eureka expanse. The radar images show a complicated structure of internal layering with ascending cross-strata, cross-bedding and bounding surfaces cutting through layers. Additional research using seismic refraction surveys and sand sampling refine the image of the subsurface (<5 m) structure. The sedimentary structure of the dune shows a strong internal layering with a cemented structure that may immobilize and influence migration of dune expanses. The subsurface features of the sand dune fields in the Mojave Desert provide evidence of dune building, wind regime and precipitation history.