Origin of the Cerro El Dragon coastal Dune, Iquique, Atacama desert, Chile

摘要

On the and coast of northernmost Chile, near the city of Iquique (20 degrees 13'S), there is a high dune that reaches an elevation of about 250 in above sea level. Several hypotheses have been proposed for the conditions and period of its genesis. Geomorphologic observations as well as sedimentological data imply that presently no supply of sand is available for the dune. Such evidence points to the relict character of the dune. Scanning electron microscopy of the surface textures of samples taken from the dune, the coastal region and inland suggests the transportation of sediments derived from both diagenetic sandstone and mature aeolian sand sheets by subaqueous action to the coast, then to be transported northerly by marine processes and eventually to be deposited as the dune sand of the Cerro El Dragon. Surface texture analysis of the quartz grains also points to the relict character of the dune.