In the past decades, several studies have evoked sedimentary structures formed by upper-regime flows, including antidunes and cyclic steps. Yet, a substantial gap remains in our understanding of these structures and their significance. Most of our knowledge on bedforms such as antidunes and cyclic steps still comes from flume experiments since their identification and interpretation from the stratigraphic record remain sparse. That is, at least in part, due to a low preservation of deposits associated with high-energy events. Commonly reported examples include antidunes and cyclic steps formed by catastrophic free-surface flows, subaqueous density currents, pyroclastic density currents, and katabatic winds.

The objective of this session is to bring together experimentalists, numerical modelers and field geologists with an expertise in sedimentology, fluid mechanics and related disciplines to shed some light on the genesis and sedimentary patterns of these sedimentary structures and the complex flow-sediment interaction that forms them.