ALBERT

Description: The Holocene flood plain of the River Rhine is a complex dynamic sedimentary system. A series of geochronological results for the Bremgarten section including optically stimulated luminescence (OSL) and radiocarbon dating was determined to improve the understanding of part of the Holocene evolution of the River Rhine. The applied single aliquot regenerative (SAR) protocols and the applied experimental studies to find the best luminescence behaviour leave us with confidence that OSL dating is a suitable method for dating fluvial sediments from large river systems. Insufficient bleaching of the sediments from Bremgarten prior to deposition seems to be not as dramatic as previously thought. OSL and radiocarbon dating results give evidence for a short period of major erosion and re-sedimentation of fluvial sediments from the “Tiefgestade” at the Bremgarten section between 500 and 600 years before present. This time period correlates with the beginning of the Little Ice Age at about AD 1450. Several severe floods occurred in Southern Germany between AD 1500 and 1750; all those floods correlate to the period of the Little Ice Age, including the destruction of the village of Neuenburg AD 1525.

Description: The loess/palaeosol sequence from the section at Schatthausen in North Baden-Württemberg gives evidence for a younger Bt horizon superimposing the last interglacial palaeosol. This result requires a more careful investigation of polygenetic superimposing palaeosols to avoid misinterpretation of the chronostratigraphic positions. The humic horizon and the underlying Bt horizon were most likely formed during two soil forming periods, as evidenced by means of palaeopedology, phytoliths and luminescence dating. The lowermost Bt horizon (Bt1) was most likely formed during the Eemian interglacial, marine isotope substage (MIS) 5e. The sediment of the uppermost Bt horizon (Bt2) was deposited about 71.5±7.4 ka ago and subsequently superimposed by soil formation most likely during early MIS 3. The Ah horizon covering the Bt gave infrared optically stimulated luminescence (IRSL) age estimates between 52.5±5.5 ka and 45.4±4.7 ka confirming soil formation during MIS 3. Periods of increased dust accumulation rates can be distinguished for the loess/palaeosol sequence by IRSL age estimates. These are from the youngest to the oldest: The Late Glacial loess (MIS 2) with a weighted mean age of 15.2±0.6 ka (N=7), the Middle Pleniglacial sediments (MIS 3) with a weighted mean age of 48.9±2.5 ka (n=4) and the Lower Pleniglacial/Early Glacial sediments (MIS 4/MIS 5) with a deposition age of 71.5±7.4 ka and older loess deposits. The IRSL age estimates are in excellent agreement with the geological estimates and correlate well with the dust peaks of Greenland Icecore record (GRIP). The loess record from Schatthausen complements the loess/palaeosol sequence from the nearby Nußloch section with the late glacial loess and its intercalcated Cryic Gleysols.

Description: Im südlichen Kaspischen Tiefland und seinen umliegenden Gebieten treten Lösse in verschiedenen geomorphologischen Positionen entlang eines rezenten Klimagradienten von subhumiden zu semiariden Verhältnissen auf. Drei Löss-Paläobodenabfolgen werden beschrieben, die im nördlichen Vorgebirge des Alborz (Profile Neka und Now Deh) und im Lösshügelland nördlich Gondbad-e Kavus (Profil Agh Band) aufgeschlossen sind. Das Profil Neka besteht aus feinkörnigem Löss, der von zwei kräftig entwickelten Paläobodenkomplexen aus Bwk-, Bt- und AhBt-Horizonten durchzogen wird. Erste Lumineszenzdatierungen weisen darauf hin, dass der obere Pedokomplex während der Sauerstoff-Isotopen-Stadien (OIS) 5a und/oder 5c gebildet wurde, während der untere das OIS 5e oder ein älteres Interglazial repräsentieren könnte. Neun hell braune oder dunkel braune bis rötlich-braune Paläoböden (CBk-, Bwk- und Bt-Horizonte) des Lösses bei Now Deh spiegeln unterschiedliche Verwitterungsintensitäten von Interglazialen und Interstadialen des Mittleren bis Oberen Pleistozäns wider. Während der obere Bt-Horizont von Now Deh wahrscheinlich mit dem OIS 5e korreliert, bilden die unteren Bt-Horizonte einen Pedokomplex, der das Interglazial des OIS 7 repräsentiert. Die Pedo-komplexe in Neka und Now Deh weisen jeweils auf polyzyklische Bodenentwicklung hin, die Bodenbildung, Bodenabtrag, Lössaufwehung und erneute Bodenbildung umfasste. In den Lösshügeln bei Agh Band bedeckt ein 40 m mächtiges, weitgehend homogenes, gipshaltiges und feinsand- sowie grobschluffreiches Lösspaket einen braunen Paläoböden (Bw(t)), der vermutlich in das letzte Interglazial zu stellen ist. Die beschriebenen Löss-Paläobodenabfolgen dokumentieren den mehrfachen Wechsel von trocken-kalten zu feucht-warmen Klimaverhältnissen mit Lössablagerung bzw. Bodenbildung. Sie stellen ausgezeichnete terrestrische Archive des quartären Klima- und Umweltwandels Nordirans dar.

Description: At the Nussloch section located south of Heidelberg, a more recently exposed new loess wall was pedologically investigated. The profiles were investigated multidisciplinarily including grain-size spectra, organic and carbonate content, magnetic susceptibility, as well as biomorphology and malacology and infrared optically stimulated luminescence (IRSL). The lower part of the Late Pleistocene includes the subdivided Eemian paleosol and the Wuermian loess about 18 m thick. A Bt horizon, a humic-rich horizon (“Humuszone”) and several tundra gleysols (“Nassböden”) of different intensity, with and without Bw horizons could be detected. Five brown soils (WB2 – WB6) are intercalated in the loess. The brown soils WB2, WB4 and WB5 correlate to interstadial periods, as evidenced by the mollusc spectra. Furthermore, WB1 correlates to one of the three Early Wuermian interstadials (“Mosbacher Humuszone”). Soil WB1 with an age estimate of about 75 ka BP represents the reduced Early Wuermian sequence. The most intensive brown soil (WB4) has the typical soil criteria of an arctic brown soil, which most likely correlates to the about 30 ka old Lohne Soil (“Lohner Boden”). The Late Wuermian loess covering the Lohne Soil is about 12 m thick and intercalated by at least ten tundra gleysols. The equivalent of the E2-Nassboden forms a tundra gley complex including also the weak brown soils WB5 and WB6. The youngest Upper Wuermian loess about 4.50 m thick covers the Eltville tephra and is designated to correlate to the E4/E5 complex. The paleopedological results are in excellent agreement with the results and interpretation by means of malacology and magnetic susceptibility enabling detailed stratigraphic and paleoclimatic reconstruction.