Crevassing of an inland dune during the 1998 flood in upper Vistula river valley (South Poland

A relatively small flood in April 1998 inundated stream valleys draining the Tarnów Plateau. The flood water of one of these streams crevassed a dune. An elongated crevasse, an irregular-shaped transport zone and a crevasse splay were formed as a result. The crevasse splay consisted of several lobes, which were separated by crevasse channels. Minor fans formed at the channel outlets. All this forms were the result of rapid processes of erosion and accumulation. The dominant lithofacies in the crevasse splay sediments were fine and medium sand with horizontal (bottomset) and low-angle (topset) stratification. Trough and planar cross-stratified medium- and coarse-grained sands appear in the middle part of the vertical sequence. Most of these sediments were laid down in a high-energy environment of a sheet flow. The phase of vanishing flow left ripple marks, encountered in the highest part of the distal splay.