Rhein loess, ice cores and deep-sea cores during MIS 2--5
published: Jan 1, 2000
Eine rheinische Löss-Boden-Folge, die die letzten 130.000 Jahre umfasst, bietet an Hand von braunen und humosen Böden eine reichere Zahl von Klima-Schwankungen der letzten Kaltzeit als bisher vom terrestrischen Bereich berichtet wurde (Abb. 3, 8). Sechzehn interstadiale Böden lassen sich tendenziell, manchmal auch bis ...
A loess and fossil soil record of the Lower Mittelrhein and Niederrhein-Maas area covering the last 130.000 years demonstrates more variability of the terrestrial climate during the Last Glacial period than has been realized up till now (Figs. 3, 8). The succession representing the last glacial period is subdivided by 16 interstadial soils. They closely seem to match the climate oscillations of the Greenland ice-core and deep-sea records in age, configuration and intensity (Fig. 9). The Eemian and Lower Würmian (ca. 130.000--67.000 a BP) is represented by the Rocourt Solcomplex comprising at least five soils: a strong luvisol, two weaker luvisols and two humic soils. It correlates with MIS 5. The Middle Würmian Ahrgau loess (ca. 67.000--28.000 BP) shows a fourfold alternation: The sequence stadial-interstadial-stadial-interstadial produces the divisions wml-4. wml: Thick solifluction loess represents the MIS 4 respectively the terrestric period of the Middle Würmian Glaciation 1 (MWG 1). wml: A bundle of five brown interstadial cambisols shows a distinct configuration of two Lower Remagen Soils (R 1--2) and three Upper Remagen Soils (R 3--5) separated by a short loess interval. wm3: A loess layer (Kripp Stadial) separating the interstadial Remagen and Sinzig Soil groups may be correlated to the Middle Würmian Glaciation 2 (MWG 2). wm4: A bundle of three Sinzig Soils is characterized by upward decreasing intensity. As a whole, wm2--4 represents the terrestric equivalent of MIS 3 and forms a conspicuous sequence likewise presented in ice and deep-see records. The Upper Würmian (ca. 28.000--12.600 BP) representing MIS 2 is subdivided into three units (wu1--3): wul: Thick loess with tendency to fine lamination (Hesbaye Loess) is intercalated by three gleyic gelisols (Nassböden), the Erbenheim Soils (El-3). Above the E3 Nassboden the Eltville Tephra forms the most reliable stratigraphic layer of the Upper Würmian. The following Eben Discordance extends widely over the Niederrhein-Maas-Sambre area. Its reworking activity produced a bed incorporating reworked older loesses and soils (Kesselt Layer). The upper part of the Kesselt Layer is suggested to host the LGM. wu2: The Brabant Loess up to 6 m thick, light coloured and preferably of eolian loess veneers the landscape. It encompasses two terrestric soils, the Elfgen Soil and the Leonard Soil and several gelic gleysols (Nassböden) of both synchronic and diachronic type. wul-2 represents MIS 2. wu3 (Late Würmian): On top of the loess, the Late Glacial palynologically starts with a weak warming (Meiendorf Interstadial) (Fig. 8), followed by a short cooling (Dryas 1), a short and pointed warming (Bolling), a slight cooling (Dryas 2), a longer warm phase (Allerod) and finally a strong cooling (Dryas 3). The late Allerod period hosts the Laacher See tephra. Eolian sand prevails during Dryas 3. Thus, the Rhein loess record for the last glacial period demonstrates the best match between terrestrial and marine/ice records reported thus far. It indicates the periods of loess deposition to cover less time than the soil-forming periods. From this evidence it is argued that the climate of the Last Glacial stage on land was warmer than has been assumed hitherto.