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Loess-paleosol sequences (LPSs) are essential records for reconstructing Quaternary paleoenvironments. No previous study has provided numerical chronologies of loess in Lower Franconia, southern Germany; their chronostratigraphic assumptions have relied mainly on German (pedo)stratigraphic schemes. In this study, we provide for the first time a chronology for LPSs in Lower Franconia based on optically stimulated luminescence (OSL) dating using quartz and a comparison of K-feldspar (63–100 µm) and the polymineral fraction (4–11 µm). Our results show that all obtained ages are in stratigraphic order, ranging from Holocene to late Pleistocene, and in general confirm the former stratigraphical interpretations. A good agreement of the obtained ages is observed between both feldspar grain size fractions; they also agree well with the quartz OSL ages up to ∼50 ka. However, a marked difference between the growth pattern of the dose response curves and consequently different saturation characteristics of fine and coarse grains is found. Even though in our samples the discrepancy in ages is not very significant, we suggest the use of coarse-grained K-feldspar whenever possible in order to not be confronted with unknowns such as the mineral composition of the polymineral fraction. Kurzfassung: Löss-Paläoboden-Sequenzen sind wichtige Archive zur Rekonstruktion der quartären Umwelt. Bisher hat sich noch keine Arbeit mit der numerischen Chronologie mainfränkischer Lösse befasst; die bisherigen chronostratigraphischen Einordnungen haben ihren Ursprung in deutschen (pedo)stratigraphischen Schemata. In der vorliegenden Arbeit stellen wir erstmals eine auf optisch stimulierter Lumineszenz (OSL) basierende Chronologie für Löss-Paläoboden-Sequenzen in Mainfranken vor. Hierzu wurden Quarz und in vergleichender Weise sowohl K-Feldspat (63–100 µm) als auch die polymineralische Feinkornfraktion (4–11 µm) verwendet. Unsere Ergebnisse zeigen, dass alle gewonnenen Alter in stratigraphischer Reihenfolge sind, vom Holozän bis zum Spätpleistozän, und generell die früher angenommenen stratigraphischen Interpretationen stützen. Eine gute Altersübereinstimmung liegt für die beiden Feldspatfraktionen vor; die Alter stimmen weiterhin mit den Quarz-OSL-Altern bis 50 ka überein. Im Vergleich von Feldspat-Grobkorn und Feinkorn (polymineralische Fraktion) zeigt sich bei jedoch ein stark voneinander abweichendes Verhalten in den Wachstumsverläufen der Dose Response Curves und ein sich daraus ergebendes unterschiedliches Sättigungsverhalten. Auch wenn die Unterschiede für die hier vorliegenden Proben nicht übermäßig groß sind, so empfehlen wir, wenn immer möglich, die Verwendung von grobkörnigem K-Feldspat für die Datierung, um nicht mit möglichen Unbekannten, wie der Mineralzusammensetzung von polymineralischen Extrakten konfrontiert zu sein. [ABSTRACT FROM AUTHOR]

Based on a W–E transect through the northern loess regions of Austria, palaeoenvironmental studies were carried out in three loess–palaeosol sequences (Gunderding, Krems-Wachtberg and Stillfried B locus typicus) to complement available results in the context of a multi-methodological approach. On the base of previously published datings, our study concentrates on the MIS 3/2 transition. The results of detailed micromorphological investigations prove that palaeopedogenesis, frost processes, and sedimentation rates differ in their spatial occurrence in the loess belt of Austria. All three sequences are in line with the general trend of a reduced intensity of pedogenic and cryogenic features from western to (south-)eastern Europe, which can be explained by lower Atlantic moisture influence towards the east. Interstadial cambic horizons are well developed in the MIS 3 sequence of western Austria, whereas the eastern loess profiles only show weak pedogenesis. In all studied sequences frost processes were active during the upper MIS 3 and MIS 2. The studied MIS 2 records are characterised by tundra soils with reductaquic horizons, which is a clear sign for prolonged phases of permafrost. On the spatial scale, the sedimentation rate increases in the eastern loess regions and particularly the Krems-Wachtberg sequence in the centre of the transect experienced an exceptionally high sedimentation rate and can thus be seen as one of the most important high resolution records for the MIS 3/2 transition in European loess regions. [ABSTRACT FROM AUTHOR]

Abstract: The Rhenodanubian Flysch zone of the eastern Alps of Austria is considered to be susceptible to landslides. In the study area, an undulating low mountain landscape of the eastern European Prealps, the Flysch bedrock is superimposed by Quaternary periglacial cover beds and loess. Both, the petrography of the bedrock and the soil mechanical properties of Quaternary sediments control the slope dynamics. A database compiled for the study area comprises about 200 datasets on landslide and rock fall hazards. It covers a time span between 1771 and 2007 and shows clusters between 1940 and 1943, 1965 and 1966, 1979 and 1982 as well as in 2006. The study analyses slope stability in the light of slope formation phases with respect to weathering, erosion and geology. Furthermore, geomorphological and soil–geographical methods are combined with soil–mechanical calculations. The application of the concept of periglacial cover beds facilitates the distinction between Holocene and Pleistocene landforms and slide masses in the research area. As a result, the study shows that the properties of Quaternary sediments and the occurrence of the densely bedded basal cover beds are responsible for landslide susceptibility. The variable permeability in loess layers, in contrast to that in the underlying basal cover beds, consisting mainly of marls and clayey material, is one of the fundamental controlling factors of mass movements. In a temporal context it is evident that the stability of slopes in the study area is influenced by several phases of slope formation. The synopsis of field survey, morphometrical, geotechnical as well as laboratory analyses, and slope-stability calculation, gives evidence of five morphodynamic phases that partly reoccur in an alternating pattern. After having passed all phases, the stability of the slopes studied is increased, because modified soil–mechanical properties of the slide masses become important. As a consequence, the critical slope angle is raised by 3-5°. [Copyright &y& Elsevier]

Abstract: In low mountain areas of central Europe, Pleistocene periglacial conditions and relevant processes have led to the formation of cover beds. In general, Holocene soils are not developed in bedrock, but they have formed in periglacial cover beds. Their occurrence and characteristics control the spatial distribution of soils, and thus periglacial sediments are a useful tool for soil mapping and soil survey. The concept of periglacial cover beds distinguishes four main layers: topmost, upper, middle and basal periglacial cover bed. The upper and middle layers contain loess, whereas the basal one consists entirely of bedrock. The loess content causes an increase of site-specific soil ecological quality in comparison to soils formed directly on bedrock. The occurrence and characteristics of the cover beds is reviewed, summarizing the present state-of-the-art. [Copyright &y& Elsevier]

Abstract: Palaeopedological, sedimentological and palaeoecological investigations were carried out on the Pleniglacial loess deposits of Duttendorf (Austria) in the area of the Pleistocene Salzach glacier. Detailed insights into the past climate, topography and vegetation, especially during the Oxygen Isotopic Stage 2 (OIS 2), were obtained. According to the results it seems that alluvial processes played a more important role for the genesis of the loess deposits during the late glacial maximum (LGM) than previously assumed. The pollen record, plant macro-remains and malaco-fauna yield the occurrence of hygrophilous taxa as well as of water plants. By consequence, the sediment can be regarded as alluvial loess. Furthermore, the results show that the landscape corresponded not only to a cold and dry loess steppe environment, but was also partly influenced by humid conditions and that probably even (small) water bodies may have existed. [Copyright &y& Elsevier]

Abstract: The loess–palaeosol sequence (LPS) in Paudorf, Lower Austria is characterised by varying dust sedimentation rates, re-deposition with admixture of local rock fragments, erosion and pedogenic overprinting. Detailed semi-quantitative micromorphological analyses reveal the complex genesis of the palaeosols/pedocomplexes and the palaeoenvironmental conditions present during their formation. Our genetic model of landscape formation is underpinned with luminescence (post-IR IRSL) ages; the resulting chronological framework indicates that the basal loess sediment was deposited during marine isotope stage (MIS) 10. The overlying lower pedocomplex experienced a complex genesis in a forest-steppe environment during MIS 9. In the sand–loess sediment of MIS 8 a (forest-)steppe palaeosol (MIS 7) developed. The overlying MIS 6 loess sediment shows several intercalated Cryosols. The upper pedocomplex is a Chernozem (MIS 5c[–a?]) developed in a mixture of re-deposited Cambisol (attributed to MIS 5e), dust and local material. This study shows that the palaeoclimatic conditions in the study region were comparable to those of Central Europe during the last two glacial periods, whereas the conditions were more comparable to the Pannonian Basin climate during the last three interglacials. [Copyright &y& Elsevier]

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 14 C-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 14 C complement each other. [ABSTRACT FROM AUTHOR]

Abstract: Feldspar infrared stimulated luminescence (IRSL) signals saturate at ∼2000 Gy, i.e. ∼500–700 ka (assuming a dose rate of 3–4 Gy/ka, typical for loess) and it is therefore theoretically possible to date Middle Pleistocene loess. However, the accuracy of age estimates is hampered by anomalous fading, which leads to significant age underestimation. Fading corrections have been proposed but these corrections are reliant on inherent assumptions and in any case are inapplicable at large doses (as the growth curve approaches saturation). Recent studies have identified a post-IR IRSL signal that shows less fading and is thus less dependent on accurate fading corrections. This study builds upon these investigations and applies a post-IR IRSL SAR dating protocol to polymineral fine-grain samples of the loess/palaeosol sequence in Stratzing, Lower Austria. After a preheat at 320 °C (60 s) and an IR bleach at 50 °C (200 s) IRSL was measured at 290 °C for 200 s; the same set of conditions were used to measure the response to a test dose. Recycling ratios, recuperation and dose recovery tests show that this protocol is suitable for the loess under investigation, although finite residual doses of up to 20 Gy are observed. For the oldest samples, the natural signal is in, or close to, saturation, indicating that fading is negligible in nature. This observation is inconsistent with the measured laboratory fading rates of 1–1.5%/decade and needs further investigation. [Copyright &y& Elsevier]

The complex interplay of dust sedimentation, pedogenesis, and erosion/reworking in the formation of loess-paleosol sequences (LPS) challenges paleoenvironmental proxies. Here we show that color and grain size are essential parameters characterizing loess profiles and support robust stratigraphies as a basis for reconstructions in the context of local geo-ecological and large-scale paleoclimatic evolution. Detailed paleoenvironmental records from the period since the arrival of anatomically modern humans to the last glacial maximum are scarce in the Alpine surroundings. The c. 7.5 m thick LPS Krems-Wachtberg, NE Austria, known for its well-preserved Upper Paleolithic context at a depth of 5.5 m, formed between 40 and 20 ka BP by quasi-continuous dust-sedimentation, interrupted by phases of incipient pedogenesis and local reworking. The new KW2015 composite is based on three sections studied and sampled at 2.5 cm resolution. Color and grain size data support a robust stratigraphy for reconstructions of the pedosedimentary evolution. The marked transition from oxidized to reduced paleosols of KW2015 around 34–35 ka corresponds to the Middle-to Upper Pleniglacial transition as part of a general cooling trend from marine isotope stage (MIS) 3 to 2, intensely modulated by millennial-scale climatic fluctuations as recorded in the Greenland ice core data. The distinct response of KW2015 to these trends highlights that reconstructing LPS evolution based on a robust stratigraphy is a prerequisite to paleoenvironmental proxy interpretation. • 7.2 m thick loess studied at the Upper Paleolithic Krems-Wachtberg site (KW2015). • Detailed KW2015 stratigraphy supported by high-resolution color and grain size data. • Complex pedosedimentary evolution challenges standard paleoenvironmental proxies. • Detailed Middle- to Upper Pleniglacial paleoenvironmental record in the NE Alpine forelands. • Distinct local response of KW2015 to large-scale paleoclimatic shifts (MIS 3/2 transition). [ABSTRACT FROM AUTHOR]