CRC806-Database Data Feed (Atom) http://crc806db.uni-koeln.de/ Distribution modeling of paleofauna in the Western Mediterranean between the Heinrich events H5 and H4 http://crc806db.uni-koeln.de/dataset/show/distribution-modeling-of-paleofauna-in-the-western-mediterranean-between-the-heinrich-ev1547725948/ 2019-01-17T11:52:27+01:00 This master’s thesis deals with species distribution modeling (SDM) for eight selected prey animals of the Neanderthals and the anatomically modern human within the framework of the Collaborative Research Center 806 ("Our way to Europe"). This research was realized for three methods in three climatically different time slices during the Late Pleistocene. One profile method, one regression method and one machine learning method were used. A model was developed that performs these three methods in order to obtain a potential distribution of the paleofauna in the Late Pleistocene and to link it to the dispersal of humans in this region. The results show that all three methods predict conditions for the presence of the species which may have hunted from both Neanderthals and anatomically modern humans. However, there are differences in the predicted regions between the individual methods for each species. Another task was to determine the best performing method. Based on this work, MaxEnt, a machine learning method, emerged as the best performing method among the applied methods. Christian Willmes;Michael Holthausen Reconstruction of Late Pleistocene paleoenvironments in southern Germany using two high-resolution loess-paleosol records http://crc806db.uni-koeln.de/dataset/show/reconstruction-of-late-pleistocene-paleoenvironments-in-southern-germany-using-two-highr1545141865/ 2018-12-18T14:04:25+01:00 Two loess-paleosol sequences from the Heilbronn Basin in southwestern Germany, Frankenbach and Talheim, have been investigated to gain information about environmental conditions during the last interglacial-glacial cycle. Since paleoenvironmental research on terrestrial archives is crucial for a better understanding of past climatic and environmental conditions, the profiles were studied using a multi-proxy approach. Applied methods include the analyses of grain-size distribution, element contents, sediment color, rock magnetism, micromorphology, and black carbon (BC) via benzene polycarboxylic acids (BPCA). The data reveal that the two profiles show large variations in conservation due to their different geomorphologic positions. Moreover, the results imply a subarctic climate with stable conditions during the Middle Pleniglacial (MIS 3) in-situ soil formation phase while the Lower Pleniglacial (MIS 4) was characterized by erosion and reworking of Eemian and Early Glacial (MIS 5) material but also by accumulation of aeolian material during the late Lower Pleniglacial (MIS 4) in Frankenbach. The results further suggest that the Rhine River floodplain has been a major source for the accumulated material in the two profiles, which indicates westerly wind directions during the time of accumulation. The low GSI and U-Ratio of Upper Pleniglacial (MIS 2) sediments, supported by the overall high content of fine material, imply a larger distance to the source area. We give an overview of loess in the Heilbronn Basin and place it in a wider context of loess in Western Europe. Jonas Viehweger The Eltville Tephra (Western Europe) age revised: Integrating stratigraphic and dating information from different Last Glacial loess localities http://crc806db.uni-koeln.de/dataset/show/the-eltville-tephra-western-europe-age-revised-integrating-stratigraphic-and-dating-info1545141459/ 2018-12-18T13:57:38+01:00 The Eltville Tephra (ET) is an important stratigraphic marker bed in the Western European loess stratigraphy at the boundary between the regional Last Glacial Maximum (LGM) in the sense of the maximum extent of glaciation of the Scandinavian ice sheet and a ‘terrestrial’ LGM with the highest degree of aridity and coldness. Stratigraphic marker beds such as tephra layers are commonly dated at more than one location, and often with more than one method. The sediments surrounding the ET were dated 87 times at 15 localities with different luminescence techniques yielding ages between 13.5 and 49.6 ka. Based on individual sections, the deposition of the ET was supposed to have taken place between 20 and 23 ka. This raises the question of whether a quantitative combination of individual ages can give a reproducible common age, including uncertainties. After screening the dataset and applying selection criteria, a Bayesian resampling approach is applied to obtain a common age consistent with a high percentage of observations from multiple localities. Four new luminescence ages bracketing the ET and two ages directly generated from the tephra horizon are presented and combined with all available data. The 1σ age range of the Bayesian age modelling yields a deposition age between 23.2 and 25.6 ka, which is in excellent agreement with two new luminescence ages from the tephra of 24.1 ± 1.9 ka (quartz) and 24.3 ± 1.8 ka (pIRIR290) and a peak of volcanic minerals in the Dehner Maar core around 24.3 ka. This age is clearly older than previously suggested for the ET volcanic eruption, but fits better with stratigraphic and paleoenvironmental evidence. Therefore, the ET was deposited during phases of strong aeolian activity of the Greenland Stadial 3. Additionally, for the first time, a correlation can be made between the ET and tephra layers recognized in the Eifel Maar lake cores. Jonas Viehweger The MIS 3/2 transition in a new loess profile at Krems-Wachtberg East - A multi-methodological approach http://crc806db.uni-koeln.de/dataset/show/the-mis-32-transition-in-a-new-loess-profile-at-kremswachtberg-east--a-multimethodologic1545139653/ 2018-12-18T13:27:32+01:00 Local to regional paleoenvironmental reactions to past climate changes are preserved in loess-paleosol sequences (LPS). In order to extract this information we used a multi-methodological approach in the Upper Paleolithic site of Krems-Wachtberg East in Lower Austria. Detailed field studies and high-resolution geochemical, colorimetric, and granulometric analyses help to understand the interplay between soil formation, loess accumulation, and surface processes. In comparison to the main profile/excavation of Krems-Wachtberg 2005–2015 it can be stated that OSL- and 14C-ages as well as the (archeological) stratigraphy of both profiles are comparable. However, pedogenic features are more evident at Krems-Wachtberg East. The new investigations show that well-established weathering indices do not clearly trace interstadial soil formation in the studied profile. Apart from this fact, single specific elements like Fe and Mg react more sensitive to initial pedogenic processes. Weak pedogenesis can further be evidenced by quantitative spectrophotometric results. The latter is also capable of refining and supporting the stratigraphy/pedology based on field analyses. As a general rule, next to loess also initial soil horizons of the MIS 3 are remarkably rich in primary carbonates indicating that soil formation took place in an alkaline environment. Due to the fact that hydrolysis of feldspars could not clearly be detected by the application of pedochemical indices, soil formation was probably limited to the oxidation of iron bearing minerals and weak carbonate leaching. These phases of favorable climatic conditions in terms of pedogenesis were terminated by increasing dust input towards the onset of MIS 2. The eolian deposits are overprinted during reducing conditions in soils and/or modified by colluvial processes. Altogether, weak pedogenesis can be reliably detected using a multi-methodological approach which leads to enhanced paleoenvironmental interpretations. The OSL-ages put the profile in a range of ∼41 to 30 ka. We present a tentative correlation of the studied loess profile to the record of the North Greenland Ice Core Project (NGRIP) for the part of the profile where OSL and 14C complement each other. Jonas Viehweger Landscape instability at the end of OIS 3 in NW-Europe: evidence from a multi proxy study on loess deposits from the eastern Lower Rhine Embayment, Germany http://crc806db.uni-koeln.de/dataset/show/landscape-instability-at-the-end-of-ois-3-in-nweurope-evidence-from-a-multi-proxy-study-1545138854/ 2018-12-18T13:14:13+01:00 The Lower Rhine Embayment hosts important Loess-Palaeosol-Sequences (LPS) within the western European loess belt yielding valuable information on landscape evolution and palaeoclimatic dynamics. The study focusses on the palaeoenvironmental development based on a LPS from the eastern shoulder of the Lower Rhine Embayment (Düsseldorf-Grafenberg). The palaeoenvironmental development within the study area is presented and discussed based on high-resolution grain size analyses, selected environmental magnetic parameters, and geochemical analyses complemented by luminescence age estimates. Differences in grain size distribution (ΔGSD) as well as the U-ratio clearly reflect main stratigraphical units within the LPS. In addition, the centered-log-ratio transformation of ΔGSD (ΔGSDclr), which is sensitive to post-depositional grain size variations, traces units of intensified soil formation. Despite no magnetic enhancement can be observed within the Grafenberg LPS, environmental magnetic parameters combined with selected geochemical analyses (Sr/Rb) provide direct information on the modification of silicates and magnetic minerals in the course of pedogenesis and diagenesis. Overall, the Grafenberg LPS contributes to the understanding of environmental conditions within the Lower Rhine Embayment particularly for the late MIS 3 and the transition to MIS 2. The LPS reflects major shifts in the geomorphic system, which are compared to palaeoenvironmental records from different archives and different geographic regions in north-western Europe indicating a direct relation to North Atlantic Climate oscillations during the last glacial period. It is shown that the Hesbaye unconformity (at the MIS 3/2 boundary) is bound to an erosional event, which can be traced over wide areas within the northern European loess belt. Jonas Viehweger