ASGP (2002), vol. 72: 191-197

CREVASSING OF AN INLAND DUNE DURING THE 1998 FLOODIN THE UPPER VISTULA RIVER VALLEY (SOUTH POLAND)

Piotr GĘBICA (1) & Tadeusz SOKOŁOWSKI (2)

(1) Institute of Geography and Spatial Organization, Polish Academy of Sciences, ul. Św. Jana 22, 31-018 Kraków, Poland, e-mail: gebica at zg.pan.krakow.pl
(2) Stanisław Staszic University of Mining and Metallurgy, Faculty of Geology, Geophysics and Environmental Protection, al. Mickiewicza 30, 30-059 Kraków, Poland, e-mail: tsokol at uci.agh.edu.pl

Gębica, P. & Sokołowski, T., 2002. Crevassing of an inland dune during the 1998 flood in upper Vistula river valley (South Poland). Annales Societatis Geologorum Poloniae, 72: 191-197.

Abstract:: 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.