The effects of wind transport on the shapes of quartz silt grains

Abstract Wind-blown terrigenous silt is a common component in marine sediment, but it is often difficult to distinguish from fluvial silt. A field experiment was conducted in the Loess Plateau of China to determine the effect of eolian transport on the shapes of detrital quartz silt grains and to define grain-shape criteria for the recognition of eolian silt. The results show that eolian transport results in a rapid downwind increase in the roundness of quartz silt grains, and that this increase in roundness is apparently due to preferential transport, or shape-sorting, of more rounded grains. This capacity for shape-sorting distinguishes eolian from fluvial transport, which has no great effect upon the shapes of quartz silt grains, and provides a petrographic criteria for the distinction of the eolian and fluvial silt components in marine sediments.