Late Pleistocene loess of the Lower Rhine

Abstract

From the Lower Rhine a compiled 25.7 m thick Late Pleistocene loess-paleosol sequence is differentiated into five lithostratigraphic units: the Rheingau Member (MIS 5), the Keldach Member (Weichselian Early Pleniglacial, GS-21.1–18, MIS 4), the Ahrgau Member (Weichselian Middle Pleniglacial, MIS 3) and the Hesbaye and Brabant Members (Weichselian Late Pleniglacial, MIS 2). It correlates well with climate fluctuations known from ice cores and deep-sea cores. The sequence was continuously sampled by 335 samples. It cuts through all essential layers and soils of the Late Pleistocene Upper Loess Formation. A continuous coarse silt index (CSI) curve shows a maximum in the Hesbaye Member (31–24 ka b2k) indicating the strongest wind conditions during the early Late Pleistocene. Further CSI highs lie in the Keldach and early Brabant Members. CSI lows are found the early and middle Rheingau Member (GI-25–?GI-22), the Jackerath-Spenrath Soils within the deeper Keldach Member (?GI-20–19), the early Ahrgau Member (GI-17–GI-12) and finally in the Elfgen Soil (GI-2) at the base of the Brabant Member. The organic carbon culminates in the Titz Humus Zone, presumably at the end of GI-21, indicating scanty oxidation during the following cold Lower Weichselian Pleniglacial period. The Garzweiler Solcomplex forming a prevailing period of soil formation between 130 and 78 ka BP (MIS 5e–a) is considered as interglacial complex (Rhine Interglacial Complex) continuing the style of the older interglacial complexes of MIS 7, 9 etc. The Ahr Interstadial Complex (MIS 3) is seen as immature complex of warm phases with fabric of the interglacial complexes. – Author's suggestion: The Rhine Interglacial Complex covers MIS 5e–a and restricts the Weichselian Glacial to MIS 4 through MIS 2. This procedure follows the style of the older interglacial complexes.