Megaripple mechanics: bimodal transport ingrained in bimodal sands

• DOI: 10.1038/s41467-021-26985-3
• Publication Date: 2022-01-10T11:02:59Z
• Authors: Katharina Tholen; Thomas Pähtz; Hezi Yizhaq; Itzhak Katra; Klaus Kroy
• Keywords: Reptation; Beach morphodynamics; Bedform; Extraterrestrial Life; Aeolian sand; Earth materials

Abstract Aeolian sand transport is a major process shaping landscapes on Earth and diverse celestial bodies. Conditions favoring bimodal transport, with fine-grain saltation driving coarse-grain reptation, give rise to the evolution of megaripples characteristic composition. Here, we derive unified phase diagram for this special aeolian ensuing nonequilibrium megaripple morphodynamics by means conceptually simple quantitative model, grounded in grain-scale physics. We establish well-preserved signature otherwise highly variable grain size distributions, namely, log-scale width (Krumbein phi scale) their peaks. A comprehensive collection terrestrial extraterrestrial data, covering wide range geographical sources environmental conditions, supports accuracy robustness unexpected theoretical finding. It could help resolve ambiguities classification sedimentary bedforms.