Osady glifu krewasowego z miocenu Polski środkowej w okolicach Konina

The paper presents results of a study of crevasse splay deposits from the Miocene of central Poland near Konin. These mineral deposits occur within the 1st Middle-Polish lignite seam of Middle Miocene age, which is exploited from the Tomislawice lignite opencast mine. They consist of fine-grained sands with an admixture of plant detritus at the top and bottom layers, where the muddy-sandy clasts are present. The investigated crevasse splay deposits are predominantly massive or horizontally stratified, and they occasionally reveal small- to large-scale (planar, trough and ripple) cross-stratification. Thus, they are interpreted as representing dense gravity flows, sheet flows, and channelized flows of variable energy. The crevasse splay was formed subaerially during sudden flood conditions on the floodplain covered by a low-lying mire with predominant herbaceous vegetation. The description of the crevasse splay deposits from the Miocene of central Poland can be helpful in better understanding the sedimentation conditions of relatively thick lignite seams.