Unravelling the key mechanisms and chronology of zebra stripe formation in the Atacama Desert (N Chile)

The Atacama Desert in northern Chile is one of the most arid regions on Earth, with an extremely hyperarid core receiving less than 2 mm of rainfall per year. In this virtually waterless world, mechanisms and rates of geomorphic processes are so far poorly understood. New detailed field data and monitoring of local conditions are hence much needed, and would ultimately provide valuable insights into geomorphic processes under extreme hyperaridity. The DFG-funded project “Key mechanisms and chronology of geomorphological processes in hyperarid landscapes” (ref. no. AG 432/1-1, MA 5768/6-1) aims to fill this knowledge gap by studying processes, drivers and time scales of hillslope sediment production and transport in hyperarid landscapes. Specifically, it aims at investigating the so-called zebra stripes, arguably the most enigmatic and widespread hillslope landform in the central Atacama Desert. Zebra stripes cover slopes between the coastal range and the pre-Andean cordilleras and are defined as contour-parallel, thin lateral bands of loose angular gravels resting on hillslopes between 4° and 30°. Backed by geomorphological and geochronological investigations from recent years, the new project will focus on repeated field geomorphological investigations at zebra stripe key sites by (i) conducting on-site monitoring of local environmental conditions and processes; and (ii) obtaining both relative and absolute chronological information on zebra stripe formation time scales utilising rock surface luminescence and terrestrial cosmogenic nuclide dating techniques. This contribution introduces the project and presents first data of monitoring and dating results.