Ground penetrating radar images of unexposed climbing dune-forms in the Ubehebe hydrovolcanic field (Death Valley, California)

Ground penetrating radar surveys were conducted in the Ubehebe hydrovolcanic field (Death Valley, California) using 900 MHz antennae, which allowed high-resolution images of the subsurface. The surveys were intended to study the lateral facies variation of subsurface sequences in base surge deposits and were run along a flow direction radial to the Ubehebe Crater. The ground penetrating radar imaged deposits that would otherwise be difficult to study because they are in an area with very few outcrops. In particular, the radar profiles show the presence of wavy reflections from relatively proximal to intermediate positions which become increasingly less wavy and more plane-parallel in distal locations. The wavy reflections have been interpreted as ground penetrating radar images of subsurface trains of climbing dune-forms, whose size decreases downflow. A climbing dune-form exposed inside a trench in correspondence to a crest of wavy reflections, confirms this interpretation. These results show that ground penetrating radar can usefully integrate traditional geologic field studies. (C) 2001 Elsevier Science Ltd All rights reserved.