A Comparative Analysis of Sediment Transport and Deposition Trends of the Sand Seas of Earth and Titan
Robert Lewis, Bradley Bishop, Jani Radebaugh
Brigham Young University, Provo, Utah, USA
Large linear dunes that form in sand seas on Earth and Saturn’s moon Titan are strikingly similar in presence and morphology, which has drawn increasing interest to the surface of Titan. Sand seas are sedimentary bodies that are transported and deposited by eolian processes. On Titan, sand seas are concentrated in the equatorial region and are very large; for example the Belet Sand Sea is approximately 3.3 ± 0.6 million km2. Sand seas on Earth vary in position latitudinally much more and most present day sand seas are significantly smaller than those on Titan. The terrestrial sand seas, the Rub’ Al Khali and the Namib Sand Sea, are good analogues for the Belet Sand Sea because of their size, presence and morphology of linear dunes and topographic basement characteristics. The dominance of linear dunes in Titan’s sand seas may result from a number of different factors. One possibility is that wind strength and direction are more consistent over long time periods than on Earth, where we observe many different kinds of dune forms within sand seas. The size and shape of the basins may also be influential, as may sediment supply. The similarity in the shapes and spatial trends of linear dunes on Earth and Titan suggests that the comparative analysis of dunes on both bodies will shed light on the wind and sediment supply necessary to form linear dunes. We have developed a method that allows for large data collection of dune width, length and spacing and that provides a better spatial correlation of these factors across the sand seas. Using Arcmap, we developed a system for measurement of width and spacing over sand seas every 500 meters along individual dunes. The data are collected by measuring the distance between segmented lines that trace along dark and bright radar boundaries, indicative of dune margins. We are currently using this method in the Belet Sand Sea on Titan but will soon transition our focus closer to home, where the method will be applied to a sand sea on Earth. In addition to understanding spatial trends we will also compare other sand sea characteristics including regional topography. We will also seek for a better understanding of the sources of sand in sand seas on Earth, which will hopefully provide insights into the sources for Titan’s sand seas. Using our method on Titan and Earth will allow for an in depth quantitative comparison, providing greater understanding regarding sediment transport and deposition throughout sand seas.