Factors controlling Mn and Zn contents in leaves of silver and downy birch in acidified soils of Central Europe and Norway.

In Central European mountain forests, foliar element concentrations (FECs) of manganese (Mn) in silver birch (Betula pendula Roth) are occasionally approximately 5000 mg kg-1 and can represent stress for these plants. Factors controlling the Mn FECs in silver birch in Central Europe and downy birch (Betula pubescens Ehrh.) in Norway have not yet been fully deciphered. In this study, the Central European silver birch specimens were sampled in 2022. The samples were analysed by X-ray fluorescence spectroscopy. Norwegian data were obtained from the literature. Mn FECs are commonly negatively correlated with magnesium and, in certain areas, with potassium. Mn FECs are simultaneously elevated with zinc (Zn), likely because of soil acidification and anthropogenic emissions. Mn FECs in birch were previously thought to be related to altitude, which was assigned to (i) downslope washes of Mn or (ii) the historical load of acid emissions. The highest Mn FECs in silver birch were found in the Harz Mountains, Germany, and have been attributed to historical atmospheric contamination and the abundance of soils on felsic silicic rocks poorly buffering acid rains. The historical emission load from iron and steel production was hypothesised to be the cause of elevated Mn and Zn FECs in the Beskid Mountains, Czech Republic. Mn FECs in birch can be used to map historical soil acidification caused by industrial emissions. Zn FECs in birches can reflect soil contamination by this element.

Deciphering timing and rates of Central German Chernozem/Phaeozem formation through high resolution single-grain luminescence dating.

Chernozems/Phaeozems are important agricultural resources and have been intensively used for millennia. However, their origin and age are still controversial. In Europe, the westernmost widespread Chernozem/Phaeozem area is located in Central Germany. In contrast to other German regions with anthropogenic Chernozems/Phaeozems, their natural origin is suggested in connection with intensive bioturbation. Yet, radiocarbon is unsuitable for decoding Chernozem/Phaeozem formation so this hypothesis remains untested, whereas single-grain luminescence dating allows to discriminate between different soil sub-processes and formation phases. We applied single-grain feldspar luminescence to a Central German Chernozem that was buried during the Bronze Age and subsequently protected from pedogenic processes. For the first time, we could directly determine timing and rate of Chernozem/Phaeozem formation in Central Europe by dating bioturbation as the dominant soil forming process. Accordingly, Chernozem/Phaeozem formation started at the latest in the Early Holocene prior to Neolithic settlement indicating a natural origin of Central German Chernozems/Phaeozems, and Chernozem/Phaeozem formation ceased around 6-5 ka when the regional climate became more humid. Our effective soil reworking rates show that earthworm bioturbation in Chernozems/Phaeozems is more intense than ant-dominated bioturbation, but significantly less intense than bioturbation by lugworms or ploughing. The latter effect allows to identify prehistoric ploughing in paleosols.

Large-scale investigations of Neolithic settlement dynamics in Central Germany based on machine learning analysis: A case study from the Weiße Elster river catchment.

The paper investigates potentials and challenges during the interpretation of prehistoric settlement dynamics based on large archaeological datasets. Exemplarily, this is carried out using a database of 1365 Neolithic sites in the Weiße Elster river catchment in Central Germany located between the southernmost part of the Northern German Plain and the Central Uplands. The recorded sites are systematically pre-processed with regard to their chronology, functional interpretation and spatial delineation. The quality of the dataset is reviewed by analyzing site distributions with respect to field surveys and modern land use. The Random Forests machine learning algorithm is used to examine the impact of terrain covariates on the depth of sites and pottery preservation. Neolithic settlement dynamics are studied using Site Exploitation Territories, and site frequencies per century are used to compare the intensity of land use with adjacent landscapes. The results show that the main trends of the Neolithic settlement dynamics can be derived from the dataset. However, Random Forests analyses indicate poor pottery preservation in the Central Uplands and a superimposition of Neolithic sites in the southernmost part of the Northern German Plain. Throughout the Neolithic the margins between soils on loess and the Weiße Elster floodplain were continuously settled, whereas only Early and Late Neolithic land use also extended into the Central Uplands. These settlement patterns are reflected in the results of the Site Exploitation Territories analyses and explained with environmental economic factors. Similar with adjacent landscapes the Middle Neolithic site frequency is lower compared to earlier and later periods.

Hydro-sedimentary provenance analyses in the Weiße Elster catchment (Central Germany): The basic dataset.

This manuscript documents geological master data and X-ray fluorescence (XRF) data of a standardized 8*8 km sampling grid of the entire Weiße Elster catchment in Central Germany. Further, the manuscript documents XRF data of a refined 4*4 km sampling grid in the proximity of Salsitz floodplain transect as well as grain size data and XRF data of Salsitz SC40 core that was recovered from the Weiße Elster floodplain. The data provide opportunities for hydro-sedimentary provenance analyses as presented in the corresponding research article by Ballasus et al. [1].

Overbank silt-clay deposition and intensive Neolithic land use in a Central European catchment - Coupled or decoupled?

Hydro-sedimentary processes such as soil erosion, sediment transport, deposition, and re-deposition influence the environmental evolution of floodplains, especially in loess-covered catchments. Holocene floodplain deposits are thus a source of information on previous hydro-sedimentary dynamics and land use in the catchment. Resulting from forest clearings in the catchment, the onset of overbank silt-clay deposition is considered as an initial and significant human-induced process affecting Central European floodplain evolution and ecosystems. However, it is difficult to separate climate-related from anthropogenic forces on depositional environments, and the complexity of the hydro-sedimentary responses is part of an ongoing debate in geoscientific, ecological, and archaeological communities. This study focuses on the Central European Weiße Elster river system, where humans have been influencing hydro-sedimentary processes since the Early Neolithic due to land-use-induced soil erosion predominantly in the loess-covered sub-basin of the middle course. A catchment-scale XRF element record of fluvial sediment sources combined with the geochemical characterisation of Holocene floodplain deposits aim for a better understanding of the interplay between past soil erosion, overbank deposition in the floodplain, and potential changes in sediment provenances. The Weiße Elster floodplain chronosequences show a geochemical differentiation into a lower (Neolithic) and an upper (post-Neolithic) overbank silt-clay deposition. The construction of a sediment source fingerprinting mixing model yields the significant finding that the Neolithic overbank silt-clay deposition reveals a remote provenance signal from the upper catchment and less from the proximal loess-covered sub-catchment. According to a systematic archaeological data survey, the upper catchment was not permanently settled and used for agriculture in the Neolithic period. This contradicts the previous assumption that Neolithic overbank silt-clay deposition primarily originates from forest clearings and subsequent farming-induced soil erosion in the catchment. From a more general perspective, further examination of existing hypotheses concerning overbank silt-clay deposition in Central European floodplains is thus in order.

Last glacial loess dynamics in the Southern Caucasus (NE-Armenia) and the phenomenon of missing loess deposition during MIS-2.

The Marine Isotope Stage (MIS) 2 is considered the coldest, driest and stormiest period during the last Glacial-Interglacial cycle in large parts of Eurasia. This resulted from strongly decreased northern hemisphere temperature and related maximum extension of northern ice sheets that strongly reinforced large-scale circulation modes such as westerlies and East Asian Winter Monsoon driven by the Siberian High. Normally, this intensified circulation is reflected by maximum loess deposition in numerous loess regions spanning Europe and Asia. However, here we present a new loess record from the Caucasus region in NE-Armenia providing evidence in support of heavily reduced or even lacking loess formation during the MIS-2. Owing to implementations of comprehensible luminescence dating work and a provenance survey using rock magnetic and geochemical data, we are able to define distinct loess formation phases and to retrace sediment transport pathways. By comparing our results to other Eurasian palaeo-records, we unveil general atmospheric circulation modes that are most likely responsible for loess formation in the Southern Caucasus. Moreover, we try to test different scenarios to explain lacking loess formation during MIS-2. In line with other archive information, we suggest that loess formation was hampered by higher regional moisture conditions caused by a southward-shift of westerlies and renewed moisture absorption over the Black Sea. Our results show that modifications of MIS-2 circulation modes induced a very heterogeneous moisture distribution, particularly in the lower mid-latitudes of Eurasia producing a juxtaposition of very dry (morphodynamically active) and moderately dry (morphodynamically stable) areas.