Search

The aim of this study is to check the validity of luminescence ages obtained from last glacial–interglacial Polish loess palaeosol sequences (LPSs) by several established current protocols, with respect to sound geomorphological and chronostratigraphic interpretations. We report 38 new optically stimulated luminescence (OSL) ages from fine-grained (4–11 µm) quartz separates extracted from four loess palaeosol sequences in Poland, measured in the Bayreuth Luminescence Laboratory, Germany. The investigated sections are situated in Lower Silesia in the southwest (Zaprężyn, Trzebnica Hills, and Biały Kościół, Strzelin Hills), the Sandomierz Upland (Złota) in central Poland, and the Volhynian Upland (Tyszowce) in the east, allowing for regional comparison. From one Silesian section (Biały Kościół) 12 new post-infrared infrared stimulated luminescence (pIRIR) ages are presented in addition to the quartz ages of identical sample material. The obtained ages are compared to already published independently elaborated middle-grain (45–63 µm) and coarse-grain (90–125 µm) quartz ages and pIRIR ages from fine grains produced in the Gliwice Luminescence Laboratory (Poland). This comparison shows that in many cases the middle- and coarse-grain quartz ages underestimate the fine-grain quartz ages, but a general rule has not been able to be established so far, likely due to different geological origin of the quartz grains. Even fine-grain quartz ages ≥∼ 50 ka may be underestimated with respect to lithostratigraphic expectations. For pIRIR ages, however, no evidence for age underestimates has been found in the studied sections, but they are more easily prone to age overestimates due to unknown residual doses at deposition in a periglacial environment. Basic agreement between the luminescence-based chronologies elaborated in the two involved laboratories can be stated for the first time in contrast to other previous studies. The observed age differences are, however, critical for the accurate time bracketing of geomorphologic and pedostratigraphic features such as ice wedging, thermokarst erosion events, and interstadial soil formations and for their attribution to marine isotope stages. Alternative interpretations are discussed including possible periglacial mirroring of pre-LGM ice advances (Ristinge and Klintholm advances) in the southwestern Baltic Sea area. The uncertainty in luminescence ages from pre-Holocene loess due to fossil ice during permafrost conditions is the major systematic error source which will be addressed but at present is far from an unambiguous solution. The present study focuses on a complex of interstadial soils now labelled L1SS1 and on harsh periglacial climate afterwards and before, yielding some unexpected results for the timing of ice wedging and thermokarst processes. In order not to leave the users alone with the decision about the most credible dating, the suggested way forwards is to simultaneously apply various luminescence dating protocols including different quartz grain sizes and pIRIR from fine polymineral grains, as an honest approach to reliable time bracketing of geomorphological processes and stratigraphic events under debate. A refinement of this approach remains challenging as far as the sole reliable dating protocol is not ensured.

The continuing development of analytical methods for investigating sedimentary records calls for iterative re‐examination of existing data sets obtained on loess‐palaeosol sequences (LPS) as archives of palaeoenvironmental change. Here, we re‐investigate two LPS (Hecklingen, Zilly) in the northern Harz foreland, Germany, being of interest due to their proximity to the Scandinavian Ice Sheet (SIS) and the position between oceanic climatic influence further west and continental influence towards the east. First, we established new quartz OSL and polymineral IRSL chronologies. Both methods show concordant ages in the upper part of the Hecklingen profile (~20–40 ka), but in the lower part IRSL underestimates OSL ages by up to ~15 ka for the period 40–60 ka. Interpretations hence refer to the OSL data set. Second, we applied Bayesian age‐depth modelling to data sets from Hecklingen to resolve inversions in the original ages, also reducing averaged 1σ uncertainty by ~19% (OSL) and ~12% (IRSL). Modelled chronologies point out phases of increased (MIS 2, early MIS 3) and reduced (middle and late MIS 3) sedimentation, but interpretation of numerical rates is problematic because of intense erosion and slope wash particularly during MIS 3. Finally, previously obtained grain‐size data were re‐investigated by end member modelling analyses. Three fundamental grain‐size distributions (loadings) explain the measured data sets and offer information on intensity and – combined with modelled OSL ages – timing of geomorphic processes. We interpret the loadings to represent (i) primary loess accumulation, (ii) postdepositional pedogenesis and/or input of aeolian fine fractions, and (iii) input of coarse aeolian material and/or slope wash. The applied modelling tools facilitate detailed understanding of site‐formation through time, allowing us to correlate a strong peak in mean grain size at ~26–24 ka to the maximum extent of the SIS and increased influence of easterly winds., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Generally, the Quaternary palaeo dune fields on the Eastern Canary Islands are built up by different dune generations which are seperated by reddish silty layers. The biogenic carbonate sands originate from the shallow marine shelf around the islands and reach the dune fields from northern direction.On northern Fuerteventura different lava flows were formed during the Late Pleistocene, and gradually interrupted the sand pathways of the dune fields close to the western coast. The sedimentation pattern in these dune fields indicates that this cut off was completed not later than 50 ka. A huge calcium carbonate crust in the outcrops marks the stratigraphic position of that final cut off. This crust was a subject of intensive debates, and was formerly linked to unstable environmental conditions. However, within the dune fields on the neigbouring island Lanzarote we did not find a comparable carbonate crust at the similar stratigraphic position. Instead, the El Jable dune field on northwestern Lanzarote shows a well-resolved dune sequence with intercalated silty layers during that period.Consequently, the dune fields on the Eastern Canary Islands point to the importance of carbonate sand transport as the main driving force within the sediment system. Finally we can conclude that unimpaired sand pathways are a mandatory prerequisite for the buildup of palaeoclimatic signals in the Quaternary dune archives.

Revealing an amazing diversity of forms, river systems have always to be interpreted as products of their specific landscapes. Extremely sensitive to external and internal forcing, they reflect the particular characteristics of climatological and geological conditions as well as the changes of these conditions. These changes are regularly preserved in depositional series whose varying sedimentary characteristics can be attributed either to palaeoclimatic variations or to tectonic activities and their corresponding changes in fluvial discharge and sediment load. What applies to fluvial sediments in general, is particularly true for river terraces. Regularly, they are regarded as valuable palaeoenvironmental and archaeological archives and their particular importance is well documented by a huge and still growing number of studies spanning a wide range of climatic and regional settings.However, the information gained from fluvial terraces and their significance for palaeoenvironmental and present-day fluvial research strongly depend on an accurate and precise dating of the terrace formation. Numerical ages are of fundamental importance for the interpretation of sedimentological, morphological and stratigraphical findings. They are essential for assessing the influence of various driving forces and for providing insights into the mechanisms and dynamics of river adjustments over variable temporal scales.In this contribution, we present luminescence ages of fluvial deposits originating from an Upper Pleistocene river terrace in a small valley located in the headwater of the Main River, Germany. For this study, several samples from various locations throughout the river longitudinal course have been analysed. Surprisingly, the determined luminescence ages for material from the lowermost part of the valley are significantly older than those from the middle section, which in turn are older than those from the valley’s upper reaches. Based on the evaluation of a high-resolution digital elevation model (DEM) and on intensive fieldwork, we can be sure that all samples originate from the very same morphological unit, a well-preserved late Pleistocene fluvial terrace.Our results suggest a diachronic alignment of sedimentation ages for fluvial deposits, starting with old ages close to the mouth of a river and getting progressively younger for locations approaching the upper reaches. If these findings are confirmed in other fluvial systems and are not only the result of very specific local conditions, they will be of great relevance for geomorphological research in fluvial landscapes. As a result, the widespread approach of deriving age estimates for fluvial terraces from numerical results merely determined for a single location appears to be inadequate and should be subjected to a critical review.

For this study, a 15-m sediment core from the Roman harbor of Ephesus has been dated with the luminescence technique. 14C age estimates from the same and a neighboring core were used for comparing and validating the luminescence dating results via a single aliquot regenerative dose (SAR) protocol: infrared stimulation of polymineral and blue stimulation of quartz. The results reveal new insights into the deposition of the sediments of the Roman harbor from 2000 BC to AD 1500 approximately. Some samples showed incomplete bleaching. The difference between the polymineral and the quartz techniques described the bleaching condition before burial. When both approaches give consistent ages, complete bleaching can be assumed. Consistent ages were further applied to the Bayesian age-depth model and discussed within the archeological context. Based on the Bayesian age-depth model, a high sedimentation rate of ca. 65 mm/year was calculated for the period of ~ 700–400 BC suggesting a fast advance of the delta front. However, other age estimates suggest a fast advance for the period 200 BC to ca. AD 100. This is probably due to incomplete bleaching of the luminescence samples and the use of bulk samples for 14C for this new study. Comparing the results with nearby cores suggests that dredging was conducted in the southern part of the Roman harbor at a depth of ca. 5 m b.s.l.

The appearances of palaeosurfaces intercalated into palaeo-dune fields on Fuerteventura are multifaceted. Although reddened layers in these dune sediments might suggest that strong soil-formation processes have taken place, the combination of aridity and parent material, namely biogenic carbonate sand of shelf origin, reveals that strong soil formation seems unlikely. These sediments rather represent de- and recalcification processes only. Solely in the case of admixed material of volcanic origin and dust deposits further soil-forming processes seem to be possible. Hematite-rich Saharan dust contributes to reddish colouration of the palaeosurfaces. In addition, CaCO3-coated iron particles appear to be ingredients of dust being leached after deposition and transformed to hematite. Overall, we propose much weaker soil-forming processes during the Pleistocene than previously postulated. Our findings support the relevance of local environments. Carbonate sands of shelf origin hinder strong soil formation and the reddish layers separating dune generations are palaeosurfaces, which mainly consist of Saharan dust. After deposition of allochthonous material, these layers are overprinted by weak soil-forming processes. The formation of palaeosurfaces primarily depends on morphodynamically stable periods during limited sand supply. Our data suggest a cyclicity of processes in the following order: (1) sand accumulation, (2) dust accumulation and weak soil formation, and (3) water-induced erosion. For the Canary Islands, we support the assumption of glacial maxima being periods of increased levels of moisture. In combination with rising sea level, we propose that favorable conditions of surface stability occur immediately after glacial maxima during periods of starting transgression, whereas regression periods immediately after sea-level high stands seem to yield the highest sand supply for the study area.

The partial neurocranium of a Neanderthal was recovered from deposits related to the latest volcanic activities recorded at the Wannen Volcanic Group. This last volcanic event provided heated mineral samples for thermoluminescence (TL) and Ar/Ar dating, allowing the estimation of the age of the hominin remains. Novel TL methods using a much less time consuming measurement protocol and employing the orange-red TL-signal (R-TL) were applied, resulting in ages of 177 ± 18 ka and 176 ± 21 ka for two samples of different geology. This new data is compared with standard TL-approaches for one of the samples, which provide an age of 187 ± 29 ka. The luminescence data is contrasted with a newly obtained Ar/Ar-age of 191 ± 12 ka for a sample from the identical heating event. All TL-dating results provide congruent results and are in perfect accordance with Ar/Ar dating, showing the applicability and accuracy of the new TL approach employed. These data also agree well with the geological age estimates and other chronometric data, placing the volcanism at Wannen to around 180–190 ka and thus providing a Saalian age of the fossil. Such an old age, however, contrasts to the reported preliminary placement of this specimen late in the Neanderthal lineage.

Robust chronologies of Late Pleistocene and Holocene volcanic eruptions are vital for hazard analysis but accurate and precise dating of these events is often difficult. Here we apply various luminescence techniques to quartz and polymineral extracts from heated crustal xenoliths enclosed in scoria and volcanically heated bedrock in the Quaternary Eifel Volcanic Field (EVF), Germany. Consistent results from red thermoluminescence (RTL) and optically stimulated luminescence (OSL) of quartz and from post-infrared infrared stimulated luminescence of polymineral material demonstrate complete luminescence signal resetting during lava emplacement and sufficient signal stability. RTL and OSL age underestimation of one sample with independently known age from the lava contact zone could be eliminated by annealing before laboratory regenerative irradiation. The average luminescence age of 33.6 ± 2.4 ka for the Wartgesberg eruption is in good agreement with independent age control, while the average age of 15.5 ± 1.1 ka for the Facher Hohe scoria cone is much younger than previously assumed. This result represents the third youngest known eruption in the EVF. Our new data are in line with the hypothesized climate-controlled triggering of Eifel volcanism and confirm that active volcanism related to asthenosphere upwelling migrates from NW to SE in the EVF.

Dieser Beitrag beschreibt zunachst die Grundlagen der Lumineszenzdatierung. Erkenntnisse und Methoden aus der Festkorperphysik sowie aus der Radiochemie spielen dabei eine grundlegende Rolle. Die Art des datierten Ereignisses – letztmalige Erhitzung oder Belichtung – eroffnet ein breites Anwendungsspektrum dieser Methode fur Zeitraume von 102 bis mehreren 105 Jahren. Durch die Zusammenarbeit von Datierern mit Geowissenschaftlern und Archaologen in den letzten etwa 50 Jahren stellen die verschiedenen Techniken der Lumineszenzdatierung heute ein unverzichtbares Hilfsmittel zur Losung geowissenschaftlicher sowie kulturhistorischer Fragestellungen dar. In this article, we describe the basic principles of luminescence dating, for which knowledge and methods of solid state physics and radiochemistry play a major role. The type of dated event – the last heating or daylight exposure – opens up a broad spectrum of applications of this method for periods ranging from 102 up to several 105 years. Through the cooperation of dating specialists with geoscientists and archaeologists, luminescence dating is nowadays an essential tool for addressing problems in Earth-science and human history.

The dune sequences of Fuerteventura mainly consist of biogenic carbonate sands which originate from the shallow marine shelf. By onshore winds those carbonate sands migrate landwards, building up sequences of different dune generations with intercalated reddish silty layers. Former studies discussed the formation of dune generations on Fuerteventura against climatic shifts, sea level changes or changing wind directions, and the more researchers just focused on the volcanism of that island but the influence of volcanism on the formation of dune archives has never been discussed. According to this, the absence of sand deposits is not always climatically controlled nor by sea level changes nor by changing wind direction. The distribution and dating (sharding and OSL dating) of deposits on northern Fuerteventura indicate that the palaeo dune fields close to the western coast were cut off from sand supply gradually, caused by different periods of volcanism. For northern Fuerteventura three main periods can be differentiated: I. Period: around 180–170 ka, II. Period: around 135 ka and III. Period: not later than 50 ka. In that course, we investigated a palaeo dune field close to the eastern coast to illustrate exemplarily the impact of volcanic activity on dune field formation and its morphology. Additionally, we aimed to extend the chrono-stratigraphic correlation of dune sequences (according to Roettig et al., 2017). Now, the correlation across the island is spanning from the western to the eastern coastline and dates back to 450 ka. In terms of luminescence dating, the layers dominated by carbonate sands show only small amount of datable minerals, whereas the material of reddish silty layers are dominated by the imprint of Saharan dust and therefore contain increased content of quartz and feldspar. In contrast to material dominated by carbonate sands the dating performed on palaeosurface material seem to reveal uniformly younger IRSL ages.

© 2018 Elsevier Ltd and INQUA. Reconstructing dust Mass Accumulation Rate (MAR) from loess deposits is critical to understanding past atmospheric mineral dust activity and requires accurate independent age models from loess deposits across Europe and Asia. Previous correlations of loess in Europe and China have tended to focus on multi-millennial timescales, with no detailed examination of dust MAR at the two ends of the Eurasian loess belt on shorter, sub-orbital scales. Here we present a detailed quartz optically stimulated luminescence (OSL) chronology from the Serbian Titel Loess Plateau (Veliki Surduk loess core) and the Chinese Loess Plateau (Lingtai section). The luminescence ages pass internal tests and show consistent increases in age with depth, with no obvious major hiatuses. However, as reported before, it seems the quartz OSL technique is only capable of accurate age determination up to accrued doses of ca. 150 Gy (ca. 30-40 ka) due to approaching field saturation of the quartz OSL signal. Two age-depth models were used to reconstruct dust MARs, where one utilises OSL data solely and the other additionally makes assumptions about sedimentation rates. Although short-term fluctuations in MAR are model dependent, general MAR patterns between the two sites are very similar, with peak MAR occurring rather late in the last glacial (ca. 13-25 ka). This suggests that at least broad scale trends in dust activity within the last glacial period may be similar at a continental scale.

Den Schwerpunkt dieser Arbeit bilden die Ergebnisse sedimentologischer, palynologischer, malakologischer und chronometrischer Untersuchungen an Sedimenten aus dem Zentralbereich des Paläoseebeckens Neumark-Nord 2. Die interdisziplinären Untersuchungen an dem 11 m mächtigen Hauptprofil A und benachbarten Profilen zeigen übereinstimmend, dass die limnische Sedimentation vom Ende des Saale-Komplexes über die Eem-Warmzeit bis in die Weichsel-Kaltzeit erfolgte. Das Profil lässt Seespiegelschwankungen mit einer generellen Tendenz der Verflachung und Verlandung sowie wechselnde Sedimentationsraten erkennen. Durch die palynologischen Untersuchungen sind außerdem mit Erosion und Sedimentumlagerungen verbundene Hiaten festgestellt worden. Eine von Laurat et al. (2006) und Mania et al. (2008, 2010) im Profil ausgewiesene zusätzliche Warmzeit, die durch eine Kaltphase von der Eem-Warmzeit separiert und zudem jünger als das Interglazial von NN1 sein soll, existiert nicht. Vor allem die palynostratigraphische, aber auch die malakologische Koinzidenz der Becken NN1 und NN2 belegt die Gleichaltrigkeit der Ablagerungen. Somit ist in Neumark-Nord zwischen der Saale-Grundmoräne der Zeitz-Phase und den periglaziären Bildungen der Weichsel-Kaltzeit nur eine Warmzeit nachweisbar, das Eem. Dies wird durch neue geochronologische Daten eindeutig verifiziert. Daher können die zuletzt von Mania et al. (2010) dokumentierten Lagerungsbeziehungen, nach denen die Beckenfolge von NN2 über der von NN1 liegen soll, nicht bestätigt werden. In Neumark-Nord werden die klimatischen Besonderheiten des Mitteldeutschen Trockengebietes während der Eem-Warmzeit deutlich. Insofern bietet der Vergleich der Eem-Vorkommen von Neumark-Nord, Gröbern und Grabschütz ein Lehrbeispiel für die standortspezifische Variabilität benachbarter synchroner Warmzeitprofile., research

This paper describes dune sand-paleosol-sequences of four pits in Northern Fuerteventura (Canary Islands). The elaborated stratigraphy is reinforced with luminescence dating to provide a first chronological estimation. Apart from a Holocene colluvial layer, the sequence spans the period from ca. 50 ka to ca. 280 ka. Paleosols were formed during glacial times and point to a standstill in sand supply. The isotopic composition of terrestrial gastropod shells retrieved from soil horizons reflects fluctuations in humidity conditions during different edaphic phases. Because eolian sands were deposited during glacial times as well, it is inferred that soil development was simply caused by a decrease in sand supply independent of climate change. Our geomorphic, geochronological and isotopic results are discussed considering different perspectives of dune sand-paleosol intercalation and more broadly, soil-forming conditions in general.

International audience

Carbonate aeolianites are important Quaternary archives at the point of intersection between marine and terrestrial systems. Since they are composed of alternating aeolian sediments and several paleosol units, these sequences are highly suitable to reconstruct palaeoenvironmental conditions. In northern Fuerteventura, at least five different areas are characterised by successions of different dune generations and paleosols. Few studies have addressed the stratigraphic order of individual dune areas. Therefore, a comprehensive consideration spanning several dune fields is needed. Here, we aim to present a detailed stratigraphy of two different dune areas and to identify the contribution of different materials (shelf origin, dust origin, volcanic origin) along with processes (accumulation, soil formation, erosion/preservation) that build up these archives. Four key sections were selected and sampled for laboratory analyses (texture, elemental composition, CaCO3 content, palaeoenvironmental magnetics, luminescence dating, and gastropod assemblages). Based on main stratigraphic features, five major sedimentary sequences were identified indicating differences in prevailing sediment supply, humidity, and volcanic activity. First luminescence dating (IRSL) of the sequences revealed sedimentation ages between 360 ka and 15 ka. Finally, we are able to demonstrate that different dune areas show comparable stratigraphic patterns, but each studied site is defined by certain characteristics depending on the respective features of the closer surrounding. The knowledge of these peculiarities and the underlying background is essential in order to correlate different sites and to attempt an appropriate environmental interpretation of the sedimentary sequences.

1) As we are working in the same and similar settings on the eastern Canary Islands and also endeavouring to establish reliable ages based on luminescence dating, we followed the numerical ages published in this paper with great interest. Since besides a wellestablished stratigraphy it is always preferable to have a robust time control, we should be happy to accept these new ages from the Rosa Negra quarry at this time (Fig. 4). However, it is essential to have some detailed explanations (methods) on the dating procedure applied by the authors. In particular, we would like to know on what material luminescence dating was conducted: Was it IRSL on feldspar, or was it OSL on quartz? Were fine or coarse grains used? Were single or multiple aliquot protocols applied? How were dose

The original version of this article, unfortunately, contained error. Corresponding author name appeared in the article is “Prakrit Nopprakrit” instead of “Prakrit Noppradit”. Given in this article is the correct author name. The original article has been corrected.

Thermoluminescence (TL) dating is a valuable tool for chronometric dating of heated minerals and has been shown to agree very well with independent age control. Comparison with argon dating of samples from identical events, however, revealed age underestimations of volcanic eruptions dated by orange-red TL (R-TL) of quartz extracts from some xenolith samples, while good agreement was obtained for others. The underestimation is attributed to an apparent signal loss (“anomalous fading”) which was experimentally observed for some, but not all samples investigated. The presence of significant amounts of feldspar or tridymite, which could be related to the observations, is excluded by IRSL (Infrared Stimulated Luminescence) and XRD analysis. While the data is not entirely conclusive, it leads to the current working hypothesis that exposure to high temperatures might be responsible for an effect similar to the anomalous fading phenomena observed for some feldspar luminescence. It therefore appears to be prudent not to sample xenoliths from high temperature context, like basalt dykes in volcanic context.

There are several competing hypotheses for theorigin of loess in Europe but quantitative evidence is stillrare. Here, Sr-Nd isotopic and bulk elemental compositionof loess from Marine Isotope Stages 2 and 3 fromthree study regions in Central Europe – Nussloch (Germany),Grub (Austria) and Tokaj (Hungary) - are analyzed.This study aims at examining differences and similaritiesof loess deposits throughout Europe, correlating loesswith potential source rocks from major mountain rangesand comparing loess with floodplain sediments from mainrivers as integrated samples of the drainage areas. The resultsshow that European loess deposits are largely uniformand that sediment sources have been rather stablein the Southern and Eastern parts of Central Europeand more variable in West Central Europe. However, themethods used are not sufficient to unequivocally confirmand reject potential sediment sources but, in combination,help to identify the most likely sediment origins. While adirect correlation of loess and potential source rocks is dif-ficult, the comparison with floodplain sediments is mostpromising and confirms previous hypotheses. Loess fromTokaj and Grub is most likely a mix of material transportedby the Danube River and sediments from the surroundingmountains. Rhine River sediments are probably the mainsource of loess at Nussloch.