The past in dust: current trends and future directions in Pleistocene geoarcheology of European loess

NWOVI.C.191.070European Prehistor

The past in dust: current trends and future directions in Pleistocene geoarcheology of European loess

Loess is a main archive of Pleistocene landscapes and environments and therefore has an important connection to the preservation and interpretation of Paleolithic sites. In Europe, anthropogenic sites have been found in loess because of past local occupation. At one extreme, sites are well preserved with minimal disturbance often accompanied by embedded proxies to estimate ecological parameters. On the other hand, loess deposits have undergone post-depositional alterations such as weathering, pedogenesis or bioturbation due to changing environmental conditions or other disturbances that obscure anthropogenic sites. We outline the current state of research and connections between Paleolithic archeology and loess research while introducing a series of subsequent regional case studies as part of a special issue. We also make recommendations for future work to incorporate a wider variety of methods to create more robust inferences on hominin and environmental evolution and their connections

Disentangling Sedimentary Pathways for the Pleniglacial Lower Danube Loess Based on Geochemical Signatures

The source of aeolian sediments such as loess has been investigated since decades. Reliable knowledge on potential dust sources is crucial to understand past climatic and environmental conditions accompanying the dispersal of early modern humans (EMH) into Europe. Provenance studies are usually performed on small sample sets and most established methods are expensive and time-consuming. Here, we present the results of high-resolution geochemical analyses performed on five loess-palaeosol sequences from the Lower Danube Basin (LDB), a region, despite its importance as a trajectory for EMH, largely underrepresented in loess provenance studies. We compare our results with geochemical data of loess-palaeosol sequences from Austria, Hungary, Serbia, and Ukraine. Based on published literature, we thus evaluate five plausible sedimentary pathways for the LDB loess: 1) the Danube alluvium (DA) pathway, which constrains the transport and re-deposition of detrital material by the Danube and its tributaries; 2) the Carpathian Bending (CB) pathway, where sediment is mainly transported from the Cretaceous to Neogene flysch of the Eastern Carpathian Bending; 3) the Eastern Carpathian (EC) pathway, in which sediment is eroded from the flysch of the Outer Eastern Carpathians, transported by rivers, and deflated by northwesterly to westerly winds; 4) the glaciofluvial (GF) pathway, where dust is deflated from glacial outwash plains in nowadays Ukraine, and 5) the Black Sea (BS) pathway, where dust originates from the exposed shelf of the Black Sea. Based on geochemical data, we consider the DA pathway to be the major sediment trajectory for loess in the LDB. Especially the sequences located close to the Danube and the Dobrogea show similarities to sites in Central and Northeast Hungary as well as Northern Serbia. For the northeastern part of the LDB, we demonstrate that dust input is mainly sourced from primary material from the Eastern Carpathians. Mineralogical estimations and geochemical data render the CB pathway as an additional substantial source of detrital material for the loess of this area. We consider the influence of the GF pathway in the LDB as negligible, whereas some minor influences of the BS pathway cannot be ruled out based on geochemical data

Quartz OSL and polymineral post IR–IRSL dating of the Požarevac loess–palaeosol sequence in north–eastern Serbia

In this study we present a luminescence investigation of samples from the Požarevac loess–palaeosol sequence (LPS) in north–eastern Serbia. The pIRIR290 signal displayed a generally good behaviour and yielded stratigraphically consistent De values. The pIRIR290 ages show very good agreement (within uncertainty) with the expected stratigraphic ages up to about 260 ka. The analyses of the 4–11 μm quartz extracts were performed in order to determine their applicability for luminescence dating. The optically stimulated luminescence (OSL) measurements showed that the fine–grained quartz systematically underestimates the expected equivalent doses for all measured samples. A comparison between natural and laboratory dose response curve showed no overlapping, not even in the lower dose range. Linear modulated –OSL analysis revealed large differences between individual samples where some quartz extracts displayed a different number of components and varying contribution of the fast component. The quartz OSL also shows thermal instability as demonstrated by pulse annealing experiments and thermal fading. For these reasons we do not consider the fine–grained quartz from the Požarevac LPS as a reliable dosimeter

Comparison of High-Resolution 14C and Luminescence-Based Chronologies of the MIS 2 Madaras Loess/Paleosol Sequence, Hungary : Implications for Chronological Studies

Numerous loess/paleosol sequences (LPS) in the Carpathian Basin span the period of Marine Isotope Stage (MIS) 2 and the last glacial maximum (LGM). Nevertheless, only two known records-Madaras and Dunaszekcso-preserve highly resolved records with absolute chronologies with minimal uncertainties, which enable the meaningful assessment of feedbacks and short-term climatic fluctuations over this period. The Madaras profile is located at the northern margin fringe of the Bacska loess plateau; Dunaszekcso, located on the Danube to its west, yields a chronology built on over 100 C-14 dates yet spans only part of MIS 2, missing half of the LGM including its peak. Here, we add to the previously published C-14 chronology for Madaras (15 dates) with an additional 17 C-14 and luminescence ages. Resulting age models built solely on quartz OSL and feldspar pIRIRSL data underestimate the C-14 based chronology, which is likely based on inaccuracies related to luminescence signal behavior; we observe age underestimations associated with unusual quartz behavior and significant signal loss, a phenomenon also observed in Serbian and Romanian loess, which may relate to non-sensitized grains from proximal sources. Our new chronology provides higher resolution than hitherto possible, yielding consistent 2 sigma uncertainties of similar to 150-200 years throughout the entire sequence. Our study indicates that the addition of further dates may not increase the chronological precision significantly. Additionally, the new age model is suitable for tackling centennial-scale changes. The mean sedimentation rate based on our new age-depth model (10.78 +/- 2.34 years/cm) is the highest yet recorded in the Carpathian Basin for MIS 2. The resolution of our age model is higher than that for the Greenland NGRIP ice core record. The referred horizons in our profile are all characterized by a drop in accumulation and a higher sand input, the latter most likely deriving from nearby re-exposed sand dunes

Geomorphological evolution of the Petrovaradin Fortress Palaeolithic site (Novi Sad, Serbia)

Two phases of archaeological investigation were performed in the Novi Sad City Museum at Petrovaradin Fortress. In this study, we summarize the results of geo-archaeological investigations of the second period of excavation inside the Novi Sad City Museum building. The fortress is situated on a Danube terrace with the top of the bedrock at ca.123 m asl. The investigated section consists of undisturbed fine-sandy silt. The grain-size distribution of the sediments indicates clearly its alluvial reworking but shows also a general similarity with typical primary loess in the region. All analyzed proxies indicate slightly stronger weathering in the upper part of the profile. Luminescence ages suggest that the investigated sequence covers the last glacial period and the terrace presumably formed during MIS 4. Subsequently, the Danube started its incision at the start of the next warmer period (MIS 3) onward. This terrace age and elevation enable us to derive an uplift rate of the terrace of ca. 0.73 mm/a for the last 60 ka, which seems to increase towards the present. Basal loessic material, in which artifacts occur, likely in the reworked position, indicate that the area close to today's Petrovaradin Fortress was already inhabited in MIS 5

The Early Upper Paleolithic Site Crvenka-At, Serbia–The First Aurignacian Lowland Occupation Site in the Southern Carpathian Basin

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