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The Deliblato Sands is among the largest uniform dune fields of Europe, with a very pronounced topography reflecting extensive past aeolian events. Although lacking numerical age data, previous researchers have hypothesized various periods of dune formation. Our research goals were to map the main morphological units of the Deliblato Sands, and to provide the first optically stimulated luminescence (OSL) ages for the major dune types. Mapping was carried out using digital elevation models, satellite images, and GPS profiles. Dune development was investigated using OSL. Several tests were performed concerning thermal treatment, signal characteristics, dose recovery, and dose distributions to assess the suitability of sediments for luminescence dating. Based on our results, two dune generations could be identified that differed in morphology and age. Older dune forms are primarily low sand-supply, hairpin-like parabolic dunes that developed from the last glacial maximum until the end of the early Holocene, then became stabilized. Younger, superimposed parabolic dunes record an intensive aeolian signal from the eighteenth and nineteenth centuries. The history of the Deliblato Sands fits with those from other European sand dune areas, and provides further details to understand paleoenvironmental changes in the region.

The most widely used dating techniques in quaternary research are the radiocarbon (14C) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for 14C dating. In these cases, 14C dating of bulk sediment may be used as a last resort. The major aim of the present study was to determine the reliability and limitations of the different fractions of the soil organic carbon (SOC) 14C ages in the Nyírség blown-sand study area, in Hungary. Therefore, the low- and high-temperature combustions of SOC (LT-SOC and HT-SOC) 14C age of fossil soils were compared with the charcoal ages from the same fossil soil layer, and their (LT-SOC, HT-SOC, and charcoal) age reliability was verified independently by applying OSL to the quartz fraction of the sediment samples. The 14C data show variable agreement with OSL ages. Charcoal fragments were collected from some of the best material for 14C dating and their ages are in agreement with the LT and HT-SOC 14C ages and OSL data. The 14C age LT-SOC gives a reliable, credible ages, which were confirmed by independent OSL measurements. If buried soils do not contain any other macroscopic remnants for 14C dating, the LT-SOC 14C ages can be used, in the case of the Nyírség study area. The LT-SOC, which is the younger fraction of the soil organic carbon, may be considered to represent the burial time of the fossil soil layer. The HT-SOC 14C ages are sometimes unrealistically older than expected and cannot be considered to be reliable.

River Maros/Mureş has one of the largest alluvial fans in the Carpathian Basin. On the surface of the fan several very wide, braided channels can be identified, resembling increased discharges during the Late Glacial. In our study we investigated the activity period of the largest channel of them, formed under a bankfull discharge three times higher than present day values. Previous investigations dated the formation of the palaeochannel to the very end of the Pleistocene by dating a point bar series upstream of the selected site. Our aim was to obtain further data on the activity period of the channel and to investigate temporal relationships between maximum palaeodischarges, deglaciation phases on the upland catchment and climatic amelioration during the Late Pleistocene. The age of sediment samples was determined by optically stimulated luminescence (OSL). The investigation of the luminescence properties of the quartz extracts also enabled the assessment of sediment delivery dynamics in comparison to other palaeochannels on the alluvial fan. OSL age results suggest that the activity of the channel is roughly coincident with, but slightly older than the previously determined ages, meaning that the main channel forming period started at 13.50±0.94 ka and must have ended by 8.64±0.82 ka. This period cannot directly be related to the major phases of glacier retreat on the upland catchments, and in terms of other high discharge channels only the activity of one overlaps with a major deglaciation phase at ~17-18 ka. Based on these, high palaeodischarges can be rather related to increased Late Glacial runoff, resulted by increasing precipitation and scarce vegetation cover on the catchment. Meanwhile, the quartz luminescence sensitivity of the investigated channel refers to fast sediment delivery from upland subcatchments. Therefore, the retreat of glaciers could affect alluvial processes on the lowland by increasing sediment availability, which contributed to the development of large braided palaeochannels.

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