Paudorf locus typicus (Lower Austria) revisited

The more than 12 m thick loess-paleosol sequence in Paudorf, Lower Austria, has been known for decades as locus typicus of the “Paudorfer Bodenbildung” (Paudorf paleosol). The upper section of the outcrop contains an up to 1 m thick pedocomplex that developed during MIS 5. The differentiated sequence of loess-like sediment below, including a more than 2 m thick pedocomplex in its basal part, is an exceptional archive of landscape evolution from the Middle Pleistocene. Herein we present detailed paleopedological and sedimentological surveys, as well as first micromorphological observations to address the sequence in its entirety and the processes leading to its genesis. Furthermore, high resolution color and carbonate analyses, as well as detailed texture analyses, have resulted in a substantial database. The studies show that the loess sediments were subject to a polygenetic development under periglacial conditions reflected in eolian silt and fine sand accumulation, admixture of local material during (mostly solifluidal) redeposition and in situ processes. Horizons with signs of pedogenesis, particularly the two pedocomplexes, document longer phases of stability; the stages of development can be correlated to equivalent sequences and seen as paleoclimatic signals where chronological data are available. The upper pedocomplex is a Chernozem of the early last glacial (MIS 5c–[a?]), which developed in a solifluidal redeposited (MIS 5d) interglacial Cambisol (MIS 5e). Cryosols, typical for MIS 6 sequences, are present in the loess sediment below. The lower pedocomplex formed during several warm stages of varying intensities, with interruptions caused by colluvial processes and admixture of eolian sediment during colder stages.researc

A comparison of polymineral and K-feldspar post-infrared infrared stimulated luminescence ages of loess from Franconia, southern Germany

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.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

Relationships between spectral features, iron oxides and colours of surface soils in northern Jordan

Ground data on spectral characteristics of Jordan's soils remain sparse, which makes the interpretation of remote sensing datasets challenging. These are, however, very useful for predicting soil properties and agricultural suitability. Previous studies have shown that soil colours correlate well with degrees of weathering intensity, as indicated by magnetic parameters and dithionite‐extractable iron (Fed) contents along a climosequence in northern Jordan. This study enlarges the database by the results of 160 bulk samples that were collected systematically from the soil surface at 40 locations. In addition to soil colour and contents of Fed, we explore mean soil reflectance spectra (MSRS) measured by analytical spectral devices (ASD) and analyse the morphological conditions of the spectra referring to the effects of iron oxides on spectral behaviours. Results show a high correlation of spectral behaviours and colour variations with Fe oxides, and no correlation with soil organic carbon Corg. The influence of the Fe oxide contents is clearly apparent in the visible range (VIS). The presence of CaCO3 increases the reflectance in all spectral ranges. Six soil groups (Gr. I ‐ Gr. VI) were discerned qualitatively and quantitatively in the study area, which largely mirror the intensity of red colour expressed by redness indices

Investigating the loess–palaeosol sequence of Bahlingen-Schönenberg (Kaiserstuhl), southwestern Germany, using a multi-methodological approach

Loess–palaeosol sequences (LPSs) are key archives for the reconstruction of Quaternary environmental conditions, but there is a lack of investigated records from the southern Upper Rhine Graben (southwestern Germany). To close this gap, a LPS at Bahlingen-Schönenberg was investigated at high resolution using a multi-method approach. Infrared stimulated luminescence screening reveals a major hiatus in the lower part of the LPS that according to luminescence dating is older than marine isotope stage (MIS) 4. The section above the hiatus formed by quasi-continuous loess sedimentation between ca. 34 and 27 ka, interrupted by phases of weak reductive pedogenesis. The fact that this pedogenesis is much weaker compared to corresponding horizons in the more northerly part of the Upper Rhine Graben could be due to regionally drier conditions caused by a different atmospheric circulation pattern at the time of deposition. Our results reinforce earlier notions that the major environmental shifts leading into the Last Glacial Maximum (LGM) of southern Central Europe significantly predate the transition of MIS 3 to 2 (ca. 29 ka). In particular, the last massive phase of loess accumulation started several thousand years prior to the arrival of glaciers in the foreland of the Alps, which raises questions regarding the source and transport paths of the dust. It is also noted that no loess dating to the LGM or the time thereafter was observed due to either a lack of deposition or later erosion.Löss-Paläoboden Sequenzen (LPS) sind Schlüsselarchive für die Rekonstruktion von quartären Umweltbedingungen, aber es mangelt an der Untersuchung solcher Abfolgen aus dem südlichen Oberrheingraben. Um diese Lücke zu schließen, wurde eine LPS bei Bahlingen-Schönenberg mit einem multimethodischen Ansatz hochauflösend untersucht. Die Untersuchung mit Infrarot Stimulierter Lumineszenz Screening zeigt einen Hiatus im unteren Teil der LPS, der laut Lumineszenzdatierungen älter ist als das Marine Isotopenstadium (MIS) 4. Der Abschnitt oberhalb des Hiatus bildete sich durch quasi-kontinuierliche Lössablagerung zwischen ca. 34 und 27 ka, unterbrochen von Phasen schwacher reduktiver Pedogenese. Da die Pedogenese im Vergleich zu entsprechenden Horizonten im nördlicheren Teil des Oberrheingrabens viel schwächer ausgeprägt ist, könnte dies auf regional trockenere Bedingungen zurückzuführen sein, verursacht durch ein anderes atmosphärisches Zirkulationsmuster zur Zeit der Ablagerung. Unsere Ergebnisse bestätigen frühere Annahmen, dass die großen Umweltveränderungen, die zum letzten glazialen Maximum (LGM) im südlichen Mitteleuropa führten, deutlich vor dem Übergang von MIS 3 zu 2 (ca. 29 ka) lagen. Insbesondere begann die letzte massive Phase der Lössakkumulation mehrere tausend Jahre vor der Ankunft der Gletscher im Alpenvorland, was Fragen zu den Quellen und Transportwegen des Staubs aufwirft. Es ist auch festzustellen, dass kein Löss aus dem LGM oder der Zeit danach gefunden wurde, entweder aufgrund fehlender Ablagerung oder späterer Erosion

Chronostratigraphy of silt-dominated Pleistocene periglacial slope deposits on Mt. Ślęża (SW, Poland): Palaeoenvironmental and pedogenic significance

Slope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified. The concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture; yet there is a remaining debate on processes and the timing of their formation. A previous study done by us at Mt. Ślęża, SW Poland, concluded that slope deposits with variable aeolian silt admixture, or its lack, have a significant influence on the pathway of soil formation. The present work builds upon this finding, by adding further granulometric and micromorphological data from three representative profiles along a toposequence, in order to refine our understanding of local slope deposits and soil formation. Additionally, seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions. The oldest aeolian deposits are of Middle Pleistocene age (>280 ± 19 ka) with interlayered palaeosol (marine isotope stage [MIS] 9 or older). Late Pleistocene slope deposits encompass the maximum loess thickness and are dated to MIS 2. Luminescence ages from the upper layers indicate shallow reworking, which we tentatively correlate to the Younger Dryas (YD). Two profiles with thick loess mantles have strong clay illuviation features, presumably formed during the Holocene. However, weak clay illuviation in the third profile with a thin loess mantle (having an age of YD) over granite regolith seems to have occurred before the Holocene, as only fragmented clay coatings (probably MIS 2 pedogenesis) could be found. © 2020 The Author

Paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial Krems-Wachtberg record (NE Austria)

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

Provenance and paleoenvironmental context of the Late Pleistocene thin aeolian silt mantles in southwestern Poland – A widespread parent material for soils

Thin loess deposits are widespread soil parent materials and important archives for paleoenvironmental reconstruction. The origin of loess in SW Poland is attributed to the Great Odra Valley (GOV), following the general concept that large rivers play a major role in regional silt supply. Yet, the precise provenance (glacier sources and/or local rocks) of silts, possibly deflated from dry GOV braided riverbeds, is not clear. Our study of thin and thick loess mantles in SW Poland for the first time indicates the provenance of thin loess based on mineralogical (MLA-SEM) and isotopic analyses (143Nd/144Nd, 87Sr/86Sr). Luminescence ages of five localities point to thin loess mantle formation during and shortly (23.0 to 17.7 ka yr) after the Last Glacial Maximum (LGM). Our isotopic data indicate that thin loess deposits in SW Poland are the mixtures of two main components – local Sudetic and Scandinavian, the latter delivered by the Fennoscandian ice sheet (FIS). Also, detailed analyses of heavy minerals show that a single mineral (e.g., hornblende) may come from both Sudetic and Scandinavian sources. This research highlights the role of the (Pleistocene) GOV in collecting and homogenizing materials, while supplying the region with fine particles to be deflated by paleowinds from open surfaces. Anomalies in mineralogy and isotopic composition are connected with influence of Sudetic mountain rivers and locally blowing silt material by katabatic winds. Regional grain size differentiation of thin loess mantles explains transport distance and altitude. © 2021 The Author

Casting new light on the chronology of the loess/paleosol sequences in Lower Austria

Der vorliegende Artikel gibt einen Überblick über neu datierte Abschnitte in bekannten Löss/Paläoboden-Sequenzen Niederösterreichs. Die Ergebnisse der Datierungen im Profil Joching deuten darauf hin, dass es im letzten Hochglazial zur Lösssedimentation kam. Die meisten erfassten Alter sind jedoch älter als das letzte Hochglazial, was auf Erosionsprozesse hindeutet, die zur Abtragung der jüngeren Lösse geführt hat. In dem Abschnitt zwischen ~28 ka and ~35 ka wurden überwiegend Tundragleye gebildet. Eine intensivere interstadiale Bodenbildung ist nicht nachzuweisen. Dieses Ergebnis kann auch für die stratigraphische Einstufung von ‚Stillfried B‘ (sensu Fink) von Bedeutung sein. Der folgende chronologische Abschnitt liegt zwischen ~35 ka and ~57 ka in Lösssedimenten mit eingeschalteten Tundragleyen. Auch dieser Abschnitt ist durch Umlagerungsprozesse charakterisiert. Im Zeitraum von ~57 ka bis ~106 ka befindet sich eine markante Zeitlücke, die vermutlich auf langandauernde und intensive Erosionsprozesse im Untersuchungsgebiet zurückzuführen ist. Die älteste Datierung in den Sedimenten des letzten Glazials mit 106 ± 12 ka befindet sich in Paudorf direkt über dem ‚Stillfried A‘- Komplex (Paudorfer Bodenbildung). Direkt unter diesem Pedokomplex, bzw. vergleichbaren Pedokomplexen treten in Lössablagerungen Alter von 124 ± 2 5 ka (Göttweig-Aigen), 159 ± 20 ka (Paudorf 1), and 170 ± 16 ka (Joching) auf. Darüber hinausgehende Alter konnten in Stratzing, Paudorf 2, Göttweig-Furth und Langenlois nachgewiesen werden

Evidence confirms an anthropic origin of Amazonian Dark Earths.

Arising from: Silva et al. Nature Communications https://doi.org/10.1038/s41467-020-20184-2 (2021