Uziarnienie odsypów środkowej Wisły (Góra Kalwaria – Warszawa)

This study aims to identify the sedimentary texture of sandbars in the Vistula River channel on the Góra Kalwaria–Warsaw section. Surface samples were collected from 7 selected bars in their upstream, central, and downstream parts. Grain-size analysis was performed using sieve and hydrometer methods. Analysis of Visher’s grain-size cumulative curves and the relationship between the mean grain size and the first percentile on the C/M Passega’s diagram provided information on the lithodynamics of the depositional environment recorded in the deposits forming large channel bars. The upstream zones of the bars are composed of coarser grains transported by traction; the coarsest grains have a mean diameter ranging from 0.35 to over 32 mm, and in some of the bars, channel lag deposits resulting from erosion were visible. The deposits forming the fronts of the bars are primarily the result of deposition from saltation with a minor contribution of graded suspension (0.125–0.71 mm).