The geomorphological and palynological situation of the Mazovian Interglacial deposits of the Domaszki profile in the Łuków Plain (E. Poland) – one of the three Mazovian successions documented in the Samica River valley (Fig. 1) – is presented. Interglacial deposits occur under the cover of glaciofluvial deposits of the valley outwash from the Wartanian Glaciation or, as in the Domaszki site, alluvial-biogenic deposits from the Vistulian Glaciation and the Holocene (Fig. 1C). The pollen spectra of lithologically varied Mazovian Interglacial deposits documented (Table, Fig. 2) several phases – the phase of boreal birch and pine-birch forests at the beginning of the interglacial warming, the phase of communities dominated by spruce and alder and then by yew in the first period of the interglacial optimum, the phase of an optimum with fir and hornbeam communities and the presence of exotic taxa (among others Pterocarya, Buxus), followed by a cooling represented by pine forests with numerous open areas.
The geomorphological evidences and pollen spectra suggest that the contemporary Samica River valley is of an old origin (from the Sanian-2 Glaciation = Elster-2 = Berezinian), and the stratigraphic hiatus including a sequence of younger Pleistocene deposits may be a result of subglacial water erosion during glaciations and / or a strong river erosion during the anaglacial and kataglacial phases.

Keywords: Mazovian Interglacial, pollen analysis, Łuków Plain, Poland