Tobias Sprafke

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

This paper presents a review on recently dated sections in well-known loess/paleosol sequences of Lower Austria. The dating results indicate that there was loess deposition during the Upper Würmian Pleniglacial as recorded in the profile Joching. However, most obtained ages are older than the Last Glacial Maximum (LGM) and therefore erosional processes, which led to the removal of younger deposits can be supposed. Soil formation between ~28 ka and ~35 ka mainly resulted in the formation of Cryosols. Hence, in the studied profiles, there is no evidence for more intense interstadial pedogenesis during this time span. This might be of particular relevance to the stratigraphy of ‘Stillfried B’ (sensu Fink). The 2 age cluster lies between ~35 ka and ~57 ka i. e. the Middle Pleniglacial (Würmian) and is dominated by loess deposits intercalated with different Cryosols. This period is also characterized by colluvial processes. There is a significant hiatus between ~57 ka and ~106 ka, a fact which might be due to long lasting and intensive erosional processes in the study areas. The oldest measured age of the Last Glacial is 106 ± 12 ka for the loess on top of ‘Stillfried A’ in Paudorf (Paudorfer Bodenbildung). Immediately below this pedocomplex and equivalents to it, ages of 124 ± 25 ka (Göttweig-Aigen), 159 ± 20 ka (Paudorf 1), and 170 ± 16 ka (Joching) were obtained in loess. Furthermore, there is evidence for older Middle Pleistocene deposits in Stratzing, Paudorf 2, Göttweig-Furth and Langenlois. (Löss-/Paläoboden sequenzen in niederösterreich im Licht neuer chronologischer Ergebnisse) Kurzfassung: 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.

A chronological framework connecting the early Upper Palaeolithic across the Central Asian piedmont

Central Asia has delivered significant paleoanthropological discoveries in the past few years. New genetic data indicate that at least two archaic human species met and interbred with anatomically modern humans as they arrived into northern Central Asia. However, data are limited: known archaeological sites with lithic assemblages generally lack human fossils, and consequently identifying the archaeological signatures of different human groups, and the timing of their occupation, remains elusive. Reliable chronologic data from sites in the region, crucial to our understanding of the timing and duration of interactions between different human species, are rare. Here we present chronologies for two open air Middle to Upper Palaeolithic (UP) sequences from the Tien Shan piedmont in southeast Kazakhstan, Maibulak and Valikhanova, which bridge southern and northern Central Asia. The chronologies, based on both quartz optically stimulated luminescence (OSL) and polymineral post-infrared infrared luminescence (pIR-IRSL) protocols, demonstrate that technological developments at the two sites differ substantially over the ∼47-19 ka time span. Some of the innovations typically associated with the earliest UP in the Altai or other parts of northeast Asia are also present in the Tien Shan piedmont. We caution against making assumptions about the directionality of spread of these technologies until a larger, better defined database of transitional sites in the region is available. Connections between the timing of occupation of regions, living area setting and paleoenvironmental conditions, while providing hypotheses worth exploring, remain inconclusive. We cautiously suggest a trend towards increasing occupation of open air sites across the Central Asian piedmont after ∼40 ka, corresponding to more humid climatic conditions which nevertheless included pulses of dust deposition. Human occupation persisted into the Last Glacial Maximum, despite cooler, and possibly drier, conditions. Our results thus provide additional data to substantiate arguments for occupation of Central Asia.

Loess distribution and related Quaternary sediments in the Carpathian Basin

ABSTRACT Supraregional (palaeo)geoecological studies require detailed knowledge of the distribution of aeolian sediments and their sources. Such spatial data can be visualised and shared in maps, but often these are constrained in their resolution or extent. This is the case for the Carpathian Basin, where cross-border maps are not detailed enough to answer many research questions. Problems occur especially along political borders due to different geological mapping standards and varying lithological definitions. Using a Geographic Information System (GIS), we compiled a map showing the distribution of loess and related Quaternary sediments in the Carpathian Basin, with unprecedented detail. We vectorised and analysed existing data (mainly from geological maps) and combined and transferred these into a common (loess) sediment classification system. This cross-border map shows the distribution of aeolian sediments in the Carpathian Basin at a scale of 1:1,500,000. For the northwestern and the southern Carpathian Basin, we added maps that clarify the extent of late Pleistocene and Holocene terrace and floodplain deposits, which were merged in the Main Map to highlight the predominant dust source areas for this region.