Luminescence dating of sediments from the Luthern Valley, central Switzerland, and implications for the chronology of the last glacial cycle

The advancing glaciers of the last glacial maximum either eroded or deeply buried older sediments in the Swiss Alpine Foreland. However, part of the S wiss Plateau was not covered by ice and is therefore an excellent area for investigating climate and environmental change during the Upper Pleistocene . Repeated fluvial sequences can be studied in several pits along the Luthe rn Valley. The chronological framework is based on lithostratigraphy, polle n analysis, U/Th dating, and, recently, heavy mineral analysis and luminesc ence dating. The oldest unit, the Untere Zeller Schotter braided river depo sit, represents cold climate conditions and presumably a glaciation prior t o the Eemian Interglaciation. The last interglacial period and the very beg inning of the last glacial cycle is represented by the Mittlere Zeller Scho tter, sediments of a meandering fluvial system. Younger braided river sedim ents, the Obere Zeller Schotter, seem to correlate with the cold climate of oxygen isotope stage (OIS) 4, Weathering of the top of the Obere Zeller Sc hotter is likely to represent the OIS 3. The advancing Reuss glacier caused erosion of the recent Luthern Valley, cutting into older sediments, with l ocal loess accumulation during the last glacial maximum as indicated by cov er sediments on top of the fluvial sequence. (C) 2001 University of Washing ton.