A b s t r a c t.In the years 2015-2022, at least several relatively large lenses of inter-lignite sands were discovered and examined in lignite opencast mines near Konin in central Poland.They were interpreted as crevasse splays formed on the surface of Mid-Miocene mires (backswamps) during periodic floods.Due to the compaction of peat and the tectonic activity of the current lignite-rich deposit areas (grabens), the crevasse splays represent various genetic-facies types and subtypes.They may be single or numerous palaeoforms creating complexes of crevasse splays.Unfortunately, these inter-lignite sand bodies pose a significant obstacle to mining activities.Nevertheless, in relation to single fossil splays described in world literature, the abundance of such palaeoforms in the vicinity of Konin allows them to be jokingly called a "swarm" of Miocene crevasse splays.
