Characterising and dating Weichselian organogenic sediments: a case study from the Lusatian ice marginal valley (Scheibe opencast mine, eastern Germany)

摘要

Dates determined with three absolute dating methods (~(14)C, luminescence and ~(230)Th/U) supported the findings of the paleobotanical investigations of the Weichselian Upper Fluvial Sequence of the Scheibe opencast mine in the Niederlausitz (Lower Lusatia, eastern Germany). They allowed to identify three units of organogenic sediments ("organogenic complexes", OC) developed as peaty and/or humic silts. Samples from the uppermost OC I unit displayed ~(14)C age ranges from 32 to 28 and 26 to 24 ka, respectively. For the latest phase, an open landscape was identified, although high arboreal values point to locally extended sparse forests. The lithologically and paleobotanically heterogeneous OC II unit (>37 ka) represents at least two periods during which organic matter accumulated in an open landscape. The uppermost subunit represents an unforested interstadial of the Middle Pleniglacial. The lowermost OC III unit has an age of about 56 ka or higher according to the ~(230)Th/U or TL dates, respectively. It represents a forested interstadial, assigned to the Early Weichselian.