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A post-IR IRSL chronology and dust mass accumulation rates of the Nosak loess-palaeosol sequence in northeastern Serbia
2020, Perić, Zoran M., Marković, Slobodan B., Sipos, György, Gavrilov, Milivoj B., Thiel, Christine, Zeeden, Christian, Murray, Andrew S.
In the Middle Danube Basin, Quaternary deposits are widely distributed in the Vojvodina region where they cover about 95% of the area. Major research during the last two decades has been focused on loess deposits in the Vojvodina region. During this period, loess in the Vojvodina region has become one of the most important Pleistocene European continental climatic and environmental records. Here we present the dating results of 15 samples taken from the Nosak loess-palaeosol sequence in northeastern Serbia in order to establish a chronology over the last three glacial–interglacial cycles. We use the pIRIR290 signal of the 4–11 μm polymineral grains. The calculated ages are within the error limits partially consistent with the proposed multi-millennial chronostratigraphy for Serbian loess. The average mass accumulation rate for the last three glacial–interglacial cycles is 265 g m−2 a−1, which is in agreement with the values of most sites in the Carpathian Basin. Our results indicate a highly variable deposition rate of loess, especially during the MIS 3 and MIS 6 stages, which is contrary to most studies conducted in Serbia where linear sedimentation rates were assumed. © 2020 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium
Smoothed millennial-scale palaeoclimatic reference data as unconventional comparison targets: Application to European loess records
2020, Zeeden, Christian, Obreht, Igor, Veres, Daniel, Kaboth-Bahr, Stefanie, Hošek, Jan, Marković, Slobodan B., Bösken, Janina, Lehmkuhl, Frank, Rolf, Christian, Hambach, Ulrich
Millennial-scale palaeoclimate variability has been documented in various terrestrial and marine palaeoclimate proxy records throughout the Northern Hemisphere for the last glacial cycle. Its clear expression and rapid shifts between different states of climate (Greenland Interstadials and Stadials) represents a correlation tool beyond the resolution of e.g. luminescence dating, especially relevant for terrestrial deposits. Usually, comparison of terrestrial proxy datasets and the Greenland ice cores indicates a complex expression of millennial-scale climate variability as recorded in terrestrial geoarchives including loess. Loess is the most widespread terrestrial geoarchive of the Quaternary and especially widespread over Eurasia. However, loess often records a smoothed representation of millennial-scale variability without all fidelity when compared to the Greenland data, this being a relevant limiting feature in integrating loess with other palaeoclimate records. To better understand the loess proxy-response to millennial-scale climate variability, we simulate a proxy signal smoothing by natural processes through application of low-pass filters of δ18O data from Greenland, a high-resolution palaeoclimate reference record, alongside speleothem isotope records from the Black Sea-Mediterranean region. We show that low-pass filters represent rather simple models for better constraining the expression of millennial-scale climate variability in low sedimentation environments, and in sediments where proxy-response signals are most likely affected by natural smoothing (by e.g. bioturbation). Interestingly, smoothed datasets from Greenland and the Black Sea-Mediterranean region are most similar in the last ~15 ka and between ~50–30 ka. Between ~30–15 ka, roughly corresponding to the Last Glacial Maximum and the deglaciation, the records show dissimilarities, challenging the construction of robust correlative time-scales in this age range. From our analysis it becomes apparent that patterns of palaeoclimate signals in loess-palaeosol sequences often might be better explained by smoothed Greenland reference data than the original high-resolution Greenland dataset, or other reference data. This opens the possibility to better assess the temporal resolution and palaeoclimate potential of loess-palaeosol sequences in recording supra-regional climate patterns, as well as to securely integrate loess with other chronologically better-resolved palaeoclimate records. © 2020, The Author(s).
A Detailed Paleoclimate Proxy Record for the Middle Danube Basin Over the Last 430 kyr: A Rock Magnetic and Colorimetric Study of the Zemun Loess-Paleosol Sequence
2021, Laag, Christian, Hambach, Ulrich, Zeeden, Christian, Lagroix, France, Guyodo, Yohan, Veres, Daniel, Jovanović, Mladjen, Marković, Slobodan B.
Herein we report on fabrication and properties of organic field-effect transistors (OFETs) based on the spray-coated films of N,N′-dioctyl naphthalene diimide (NDIC8) doped with 2.4 wt% of poly (3-hexylthiophene) (P3HT). OFETs with the untreated NDIC8:P3HT films revealed electron conductivity [μe* = 5 × 10–4 cm2×(Vs)−1]. After the annealing in chloroform vapor the NDIC8:P3HT films revealed the hole transport only [μh* = 0.9 × 10–4 cm2×(Vs)−1]. Due to the chemical nature and energy levels, the hole transport was not expected for NDIC8-based system. Polarized optical- and scanning electron microscopies indicated that the solvent vapor annealing of the NDIC8:P3HT films caused a transition of their fine-grained morphology to the network of branched, dendritic crystallites. Grazing incidence wide-angle X-ray scattering studies indicated that the above transition was accompanied by a change in the crystal structure of NDIC8. The isotropic crystal structure of NDIC8 in the untreated film was identical to the known crystal structure of the bulk NDIC8. After the solvent annealing the crystal structure of NDIC8 changed to a not-yet-reported polymorph, that, unlike in the untreated film, was partially oriented with respect to the OFET substrate.
The Early Upper Paleolithic Site Crvenka-At, Serbia–The First Aurignacian Lowland Occupation Site in the Southern Carpathian Basin
2021, Nett, Janina J., Chu, Wei, Fischer, Peter, Hambach, Ulrich, Klasen, Nicole, Zeeden, Christian, Obreht, Igor, Obrocki, Lea, Pötter, Stephan, Gavrilov, Milivoj B., Vött, Andreas, Mihailović, Dušan, Marković, Slobodan B., Lehmkuhl, Frank
The Carpathian Basin is a key region for understanding modern human expansion into western Eurasia during the Late Pleistocene because of numerous early hominid fossil find spots. However, the corresponding archeological record remains less understood due to a paucity of well dated, contextualized sites. To help rectify this, we excavated and sampled Crvenka-At (Serbia), one of the largest Upper Paleolithic sites in the region to obtain radiometric ages for the archeological artifacts and evaluate their depositional context and subsequent site formation processes. Our results confirm that this locality represents a multiple-occupation Aurignacian site that dates to 36.4 ± 2.8 ka based on modeling of luminescence ages. Electrical resistivity tomography measurements indicate that the site formed on a sandy-gravelly fill terrace covered by overbank deposits. Complex grain size distributions further suggest site formation in contrasting depositional environments typically occurring alongside fluvial channels, at lakeshores, in alluvial fan or delta settings. The site is thus the closest (ca. 50 km) known Aurignacian site to the earliest undisputed modern human remains in Europe at the Peştera cu oase and some intervals of the occupation may therefore have been contemporaneous with them. This suggests that modern humans, during their initial settlement of Europe, exploited a wider range of topographic and ecological settings than previously posited. Our findings indicate that lowland areas of the Carpathian Basin are an important part of understanding the early settlement patterns of modern humans in Europe.