Whirlwinds, dry convective helical vortices, move large gypsum crystals in the Andes Mountains of northern Chile. The crystals are entrained from a saline pan surface, where they grew in shallow surface brines. They are transported as much as 5 km and deposited in large dune-like mounds. The dune gravel is cemented relatively quickly by gypsum cement precipitating from near-surface saline groundwater, resulting in gypsum breccia. This marks the first occurrence of gravel-sized grains moved efficiently in air by suspension, provides a new possible interpretation for some ancient breccias and conglomerates, and improves understanding of limits of extremity of Earth surface environments.
- Received 27 June 2016.
- Revision received 18 January 2017.
- Accepted 19 January 2017.
- © Geological Society of America