Radiocarbon age of Late Pleistocene glacigenic sediments in jonionys section of Merkinė (Eemian) interglacial

The stratotype of Merkinë (Eemian) interglacial in Lithuania is the Jonionys section near Merkinë town in south Lithuania. The lacustrine sediments containing rich fossil flora in this section were formed under the conditions of Merkinė interglacial and Nemunas (Vistulian) glacial. The fossil-bearing Merkinė deposits are overlain by a probably complete sequence of Early Nemunas and partly of Middle Nemunas deposits. Rewashed till-covered organic sediments were found in the upper part of Jonionys section. The exact age of glacial sediments of this section has remained largely unknown. Peat with wood remnants under the rewashed till have been investigated in Gliwice Radiocarbon Laboratory (Gd-10825: 31,500+2300/-1800 BP and Gd-14000: >31,000 BP). Its deposition probably took place just before the maximum of the last glaciation. In Jonionys section the Merkinë interglacial, Early and Middle Nemunas nonglacial sediments were probably accumulated in the time of climatic fluctuations, but without glacigenic sedimentation. The glacigenic sediments in the upper part of Jonionys stratotype section are younger than 30,000 BP and belong to the Late Nemunas glacial maximum. Recent radiocarbon dating are important for the establishment of the standard area of the European Würm (Vistulian, Valdaian, Poozerian and Nemunas) glacial.