An MIS 8 terrestrial record retrieved from a glacially overdeepened basin in the northern foreland of the European Alps

Abstract. Sediments preserved in glacially overdeepened structures can provide a record of the regional Pleistocene glacial dynamics beyond the last glaciation. In order to unravel the glacial dynamics of the Isar-Loisach paleo-glacier, a cored sedimentary succession (ICDP-DOVE 5068_3_A) from an overdeepened basin near Schäftlarn, south of Munich, Germany, and an outcrop in its northern foreland (“Münchner Klettergarten” near Baierbrunn, on the southern margin of the Munich gravel plain, the “Münchner Schotterebene”) were investigated with a multi-method approach. This approach focused on single-grain feldspar luminescence dating to establish a chronological framework and on a comprehensive geophysical survey to better understand the morphology of the overdeepened basin. The Schäftlarn core is generally divided into a fine-grained basal section and a coarse-grained top section. The filling of the fine-grained basal section started in early Marine Isotope Stage (MIS) 8. The basal part of the overlying coarse-grained sediment can be attributed to late MIS 8. The “Münchner Klettergarten” outcrop to the north exhibited a similar depositional age dating to late MIS 8 and therefore corresponding to the basal part of the coarse-grained sediment in Schäftlarn. The geophysical survey revealed two cross-cutting glacial basins, with the MIS 8 basin being cut by a younger basin of undetermined age. Based on the luminescence dating results and the geophysical survey, a mid-Pleistocene landscape development model of the Isar-Loisach paleo-glacier region is presented.