Search

This study aims to explain the influence of sediments and landforms of postglacial and loess landscapes of Europe on processes forming meandering and anabranching rivers. Based on a literature review, sedimentary architecture, types and grain-size of deposits, and channel planform changes since the Late Pleniglacial were collected for extensive set of European rivers. These data were used to create a conceptual model explaining the evolution of meandering and anabranching rivers in both types of landscape. The present study shows that the inheritance of glacial and fluvioglacial landforms and sediments, and loess formation, influence types of processes forming anabranching and meandering rivers. Point bar accretion formed meandering rivers in postglacial zone whereas oblique accretion dominated in loess areas. Anabranching rivers of postglacial zone evolved through the formation of crevasse channels and meandering anabranches. Anabranching rivers of loess zone formed sustained bifurcations. Postglacial and loess rivers reacted differently to increased deposition and humidity in the Late-Holocene. Meanders of postglacial zone formed channel bars owing to increase in stream power and sediment load. In cases of flow energy decrease, and sustained upstream sediment delivery, they turned into anastomosing rivers. Anabranching rivers in ice-marginal valleys maintained its courses until hydro technical works in the 19th century. Low-energy meandering rivers of loess areas became wetlands owing to deposition of silts. High-energy meandering and anabranching rivers maintained the planforms throughout the Holocene. These findings need to be refined by detailed studies on the evolution of rivers in subarctic zone, and large rivers of Europe. [ABSTRACT FROM AUTHOR]

In archaeology, predictive models play a key role in understanding the interactions between humans and the palaeo-environment. They are also of great value for cultural heritage management and planning purposes. This is particularly true for Palaeolithic sites in the east Austrian loess landscape, which are often deeply embedded in sediment sequences. In this study, we analyse the geospatial behaviour of 23 Upper Palaeolithic sites in Lower Austria. Hereby, we apply a new approach, which combines the advantages of a classical deductive method with the capabilities of machine learning, implemented via the MaxEnt software. The result is a predictive model for an area of 7850 km², exploring the potential for the presence of Upper Palaeolithic sites. The model highlights several spatial dynamics of site probability in the study area. Possible sources of inaccuracies within the source data and the methodology are critically discussed.

In archaeology, predictive models play a key role in understanding the interactions between humans and the palaeo-environment. They are also of great value for cultural heritage management and planning purposes. This is particularly true for Palaeolithic sites in the east Austrian loess landscape, which are often deeply embedded in sediment sequences. In this study, we analyse the geospatial behaviour of 23 Upper Palaeolithic sites in Lower Austria. Hereby, we apply a new approach, which combines the advantages of a classical deductive method with the capabilities of machine learning, implemented via the MaxEnt software. The result is a predictive model for an area of 7850 km², exploring the potential for the presence of Upper Palaeolithic sites. The model highlights several spatial dynamics of site probability in the study area. Possible sources of inaccuracies within the source data and the methodology are critically discussed. [ABSTRACT FROM AUTHOR]

Purpose: Loess landscapes are highly susceptible to soil erosion, which affects soil stability and productivity. Erosion is non-linear in time and space and determines whether soils form or degrade. While the spatial variability of erosion is often assessed by either modelling or on-site measurements, temporal trends over decades to millennia are very often lacking. In this study, we determined long- and short-term erosion rates to trace the dynamics of loess deposits in south-western Poland. Materials and methods: We quantified long-term (millennial) erosion rates using cosmogenic (in situ 10Be) and short-term (decadal) rates with fallout radionuclides (239+240Pu). Erosion processes were studied in two slope-soil transects (12 soil pits) with variable erosion features. As a reference site, an undisturbed soil profile under natural forest was sampled. Results and discussion: The long-term erosion rates ranged between 0.44 and 0.85 t ha−1 year−1, whereas the short-term erosion rates varied from 1.2 to 10.9 t ha−1 year−1 and seem to be reliable. The short-term erosion rates are up to 10 times higher than the long-term rates. The soil erosion rates are quite consistent with the terrain relief, with erosion increasing in the steeper slope sections and decreasing in the lower parts of the slope, while still maintaining high values. Conclusions: Soil erosion rates have increased during the last few decades owing to agriculture intensification and probably climate change. The measured values lie far above tolerable erosion rates, and the soils were found to be strongly imbalanced and exhibit a drastic shallowing of the productive soils horizons. [ABSTRACT FROM AUTHOR]

Plant succession is quite a common phenomenon in Poland, especially in agricultural landscapes. At the turn of the 21st century there was a significant increase in the area of fallow lands. That increased the area occupied by ruderal and segetal vegetation. The development of vegetation on post-agricultural lands transforms soils. The aim of this paper is to determine changes in vegetation and soil properties that occur as a result of secondary succession on post-agricultural lands in loess landscapes

A maximum Holocene afforestation occurred during the Atlantic phase in Central Europe and the first deforestation was human-induced by introducing Neolithic farming. However, the results of new multidisciplinary off-site and on-site investigations in southern Poland have revealed that in the loessic areas a persistence of plant and animal species of open landscape was possible throughout the mid-Holocene. The palynological and malacological data from Mozgawa (Nida Basin), from a phase preceding the human occupation and corresponding to the 5th millennium BC, show that the loessic plateau was forested with partly open pine-oak forests, but patches of open vegetation were also present. During the first half of the 4th millennium BC the first farmers related with the Funnel Beaker (= TRB) culture appeared in Mozgawa and built a long-lasted settlement extended over 35 ha site. The pollen zone related to this Neolithic settlement phase contained a record of disturbances of the forest communities and/or the reduction of forest cover at a small, local scale, accompanied by an increase of representation of herbaceous plants associated with wet and dry grasslands. The anthracological results confirm the presence of pine-oak forest near the human settlement, while malacological ( Vallonia pulchella and Chondrula tridens ), zooarchaeological ( Equus ferus ), and carpological data ( Stipa sp.) indicate the continuous presence of open vegetation in the area. During the Neolithic occupation of the Mozgawa settlement, processes of slope erosion were initiated and created the thick layer of mineral diluvium at the bottom of the loessic hill. These data reveal the first intensive human impacts onthe local wooded steppe-like landscape and the beginning of the development of anthropogenic vegetation in the region. [ABSTRACT FROM AUTHOR]

The Nałęczów Plateau is characterised by the presence of a peculiar complex of loess relief forms, among which closed depressions are the most characteristic features (Maruszczak 1958). 1,761 closed depressions were documented within the Nałęczów Plateau (Kołodyńska-Gawrysiak, Chabudziński 2012). They are small landforms with peculiar distribution and morphometric characteristics such as the dimensions of their longer axis and their size. The longer axis of more than half of the depressions (51.39%) is within the narrow range from 25 to 50 m. The size of 70% of all forms does not exceed 1,500 m2. These forms are also typified by a characteristic distribution in relation to the elements of loess relief. Their greatest concentration is on the plateau tops where 72% of all forms were documented. Closed depressions also occur in denudation troughs (16% of the forms), bottoms of erosion-denudation valleys (5%) and slopes (7%). Areas of concentration with 30-40 forms per km2 can be clearly distinguished in the spatial arrangement. Eleven areas of concentration, referred to as closed depression microregions, were identified in the study area (Kołodyńska-Gawrysiak, Chabudziński 2012). So far, the origins of closed depressions in the loess areas in Poland have been linked with the development of piping processes within initial depressions associated with the dynamics of the loess cover sedimentation (Maruszczak 1954). The most recent research indicates that the development of closed depressions may have been determined by cryogenic processes (Kołodyńska-Gawrysiak et al. in print). In Poland, closed depressions were studied in the loess areas of the Lublin Upland (Maruszczak 1954; Konecka-Betley, Maruszczak 1993; Kołodyńska-Gawrysiak, Chabudziński 2012; Kołodyńska-Gawrysiak et al. 2012), Sandomierz Upland (Czarnecki, Lewartowska-Urbańska 1987; Czarnecki, Solnceva 1992) and Carpathian Foothills (Wojtanowicz 1997). Closed depressions were also studied in France (Pissart 1958), the United Kingdom (Prince 1961), central Belgium (Gillijns et al. 2005; Vanwalleghem et al. 2007; Etienne et al. 2011) and Russia (Zanin 1952). The landscape of the Nałęczów Plateau is determined not only by the peculiar land relief but also the type of land use - which is determined by the former (Zgłobicki, Baran-Zgłobicka 2012). In terms of land use, agricultural landscape dominates in the Nałęczów Plateau. More than 82% of the region is covered by agricultural land, mostly arable fields accounting for more than 53%. Forest areas have been preserved in the form of small complexes covering a total of 4,239 ha, i.e. 8.5% of the region (Corine Landcover 2006) Zagłębienia bezodpływowe należą do głównych, a jednocześnie osobliwych elementów rzeźby obszarów lessowych. Celem badań była próba klasyfikacji zagłębień na podstawie ich cech zewnętrznych oraz określenie funkcji, jaką formy te pełnią we współczesnym krajobrazie obszarów lessowych Płaskowyżu Nałęczowskiego. Klasyfikacji zagłębień dokonano w oparciu o kryteria geomorfologiczne, hydrograficzne oraz użytkowanie terenu. Zagłębienia bezodpływowe, mimo iż są to drobne formy rzeźby, pełnią ważną funkcję we współczesnym krajobrazie Płaskowyżu Nałęczowskiego. Funkcję tę można rozpatrywać w aspekcie geomorfologicznym, ekologicznym oraz estetycznym. Z punktu widzenia geomorfologicznego, funkcja zagłębień wyraża się w ich wpływie na georóżnorodność obszarów lessowych. Na terenie wierzchowin tworzą one specyficzny mikrorelief, który urozmaica rzeźbę. W aspekcie ekologicznym, zagłębienia bezodpływowe korzystnie wpływają na bioróżnorodność obszarów użytkowanych rolniczo. Największe znaczenie pod tym względem mają zagłębienia z wodą stałą oraz periodyczną. Dzięki porastającej je roślinności leśnej oraz wodno- i wilgociolubnej bezpośrednio sąsiadującej z roślinnością pól uprawnych, wprowadzają one do krajobrazu kontrasty przyrodnicze oraz zróżnicowanie siedlisk, wpływające korzystnie na różnorodność gatunkową. Zagłębienia periodycznie wypełniające się wodą stanowią swoistego rodzaju wyspy kontrastujące typem roślinności z otaczającymi terenami pól uprawnych. Kępy drzew i zarośli stanowią osobliwe dominanty w krajobrazie monotonnych, silnie odlesionych wierzchowin lessowych, podnosząc ich walory estetyczne [ABSTRACT FROM AUTHOR]

Original vertical joints (OVJs), which are highly correlated with loess anisotropy, have been considered a non-tectonic source of extensive erosion, gully development, and landform fragmentation in loess regions such as the Chinese Loess Plateau. The existing literature discussing the origin of OVJs lacks a systematic overview of the current theories related to OVJ genetic mechanisms, development patterns, theoretical models, and relationships between OVJ morphologies and loess historical sedimentary processes (LHSP) since the Quaternary. By reviewing the key factors governing the formation and evolution of OVJs in loess, we present both a conceptual framework and a case study to demonstrate the genesis and dynamics of OVJs in the loess landscape. We propose that when the driving force produced by the hydro-mechanical coupling regime exceeds the resistance force due to tensile strength, OVJs appear along the boundaries between different structural units within the loess soils. Influenced by the loess sedimentary effects in the later period (i.e., LHSP), such as loess pile thickening, drying-wetting cycles, and weathering, OVJs formed in historical loess frequently degrade and expand. Based on the knowledge of OVJ dynamics, we reconstruct the evolutionary trajectory of OVJs in the loess profile from the LHSP perspective, which is further confirmed by field observations on OVJ morphologies under different local microtopographical and geological conditions. The new perspective on the genesis, development, and evolution of OVJs enhances theoretical understanding of the formation of anisotropy and structural evolution in loess, which helps describe and model subsurface hydrology and geohazard risks in loess regions. • A framework summarizing key factors controlling OVJ evolution in loess landscapes is proposed. • A model representing hydro-mechanical coupling between OVJ and loess is established. • The formation, expansion, and degradation of OVJ in loess are discussed. • Field observations on OVJ morphologies confirm its evolutionary trajectory based on loess historical sedimentation. [ABSTRACT FROM AUTHOR]

• Three fluvial phases identified in the Sió valley floor (Transdanubia, Hungary). • First evidence for large-scale meanders in Transdanubia in the Late Pleniglacial. • Isolation by loess hills favored formation of anabranching channels ~18000 cal. BP. • Small meanders formed by incision, evolved in the Holocene in aggradation conditions. • The fluvial phases differ in timing and type of planform in other rivers of Europe. Knowledge about the evolution of rivers planforms in loess landscapes of Europe is incomplete. While there are studies on river evolution conducted in loess areas of central and western Europe, the area of Transdanubia (Hungary) remains poorly recognized. Our research work extends previous findings by studying a unique example of alluvial fill maintaining a sedimentary record of river planforms from the Late Pleistocene to the modern times (the Sió Valley, Hungary). The main goal was to determine the main fluvial phases shaping the valley floor. Our study was based on geological, geophysical and remote sensing methods supported by AMS radiocarbon and OSL dating. Three fluvial phases were identified: the formation of large-scale meanders in the Late Peniglacial, transition to an anabranching pattern ~18000 cal. BP, and formation of small-scale meanders ~12700 cal. BP. Their traces are present in the sedimentary record of other rivers evolving in loess landscapes, however, their appearance differs in the timing and type of river planform changes. Phase I was marked by large-scale meanders in the Great Hungarian Plain and Transdanubia, and braided rivers in western Europe. Phase II, marked by transitions to anabranching planforms, or periods of meander cutoffs, appeared first in the Late Pleniglacial in isolated valleys of Transdanubia and northern part of the Pannonian basin. The latest appearance of this phase took place in western Europe owing to a cooler climate and sparse vegetation compared to Transdanubia and Great Hungarian Plain. Phase III, marked by transitions from anabranching rivers to small-scale meanders, started in the Sió valley in conditions of sediment deficit causing river bed incision. Aggradation appeared owing to anthropogenic influence starting ~7000 cal. BP. Its maximum occurred 3000–4000 cal. BP. This triggered phase III in western Europe, and increased deposition of fines, resulting in flow discontinuation in some valleys of Transdanubia. [ABSTRACT FROM AUTHOR]