Three Dimensional Visualization and Analysis of an Eolian Dune
Three-dimensional (3D) ground penetrating radar (GPR) imaging can be utilized to understand the internal stratigraphy of eolian sand dunes. The 3D software allows for slices to be made in a data cube that can aid in showing continuity of reflection patterns, as well as visualizing the internal stratigraphy from any perspective. Because the internal layering of an eolian sand dune is often exposed through coring or digging of trenches, GPR data collection can be beneficial since it allows the data to be collected in a non-invasive, non-destructive manner. A 3D grid was collected from a quartz arenite dune complex within the Early Jurassic Navajo Sandstone located in the Checkerboard Mesa area of Zion National Park, Utah. Using a pulseEKKO 1000 GPR system with an antenna frequency of 225 MHz, a 4 x 10m grid was collected. Data was plotted and processed using pulseEKKO software. A 3D cube was created using T3D which allowed for the depositional framework of stratigraphic units of interest to be visualized and interpreted. The findings showed a continuous, horizontal reflection at 90 ns (5m) and 200 ns (10.5m). The data also showed that the upper set of dipping reflections was inclined at an angle of 13-15° and the underlying dipping reflections were at an angle of 18-20°. Interpretations of the 3D cube suggest the inclined reflections are dune forsets and the horizontal reflections are erosional truncations formed by dune migration. Based on the 3D interpretations one can provide information on dune size, shape, and migratory patterns.