Stratigraphy of Late Mid-Pleistocene in Lithuania: the current status and issues /

The principal aim of this paper is to present a critical overview of the stratigraphical subdivision and correlation of the Late Mid-Pleistocene (LMP) sediments in Lithuania. In recent decades, a number of studies of LMP sediments have been carried out, allowing clarification of the stratigraphical position of individual sedimentary sections. Particular efforts have been made to determine the age of sediments using a variety of absolute age determination methods. However, there are still several outstanding questions. It is still unclear how many warm periods occurred during the Saalian in Lithuania and of what magnitude. The least problematic issue is identification of the Butėnai (Holsteinian) Interglacial as it correlates well biostratigraphically with the contemporaneous sections of adjacent areas. The most controversial unit is the Snaigupėlė Interglacial, the age of which continues to be a subject of debate. Recently, more evidence has emerged that the sediments considered to be of the Snaigupėlė Interglacial are contemporaneous with the Merkinė (Eemian) Interglacial. The chronological placement of these sediments closely hinges on the unresolved stratigraphical classification of the Medininkai deposits (MIS 6 or MIS 8?) and the Žemaitija tills (MIS 8 or MIS 10?). The debate is centred on whether these two tills were formed during two entirely different glaciations or represent different phases of a single major glaciation event. Traditionally, these two tills were attributed to distinct glaciation events separated by the Snaigupėlė Interglacial. However, no sedimentary sections have been discovered that contain both these tills and the interglacial sediments that separate them. Given the similar lithological, geochemical and petrographic composition of the Medininkai and Žemaitija tills some research has supported their possible stadial rank. The clarification of these stratigraphical issues in the future may be facilitated by the application of new proxies and re-examination of the existing LMP key sections

Holocene environmental changes inferred from palaeobotanical data of Curonian Lagoon sediments /

Environmental development and water level changes in the south-western part of the Curonian Lagoon are reconstructed based on the results of bottom sediment investigations, including data on lithology, diatoms, pollen, and radiocarbon dating. Three stages have been identified in the ~ 10000-year history of the lagoon’s development. The diatoms suggest that in the Early Holocene, the southern part of the Curonian Lagoon was a shallow freshwater basin, mainly fed by run-off from the continent. During the Middle Holocene, the study area was a marshy coastal zone. Due to a change in hydrological conditions at the beginning of the Late Holocene, it became an open-water part of the lagoon

The basin-landscape approach to the protection and condition optimization of the lakes of the national parks

The essence of the basin-landscape approach to the protection of the lakes of the national parks as an ac-tual direction of research, which is formed at the junction of nature protection landscaping, hydrology and geoecology has been substantiated. The research algorithm, peculiarities of analysis and assessment of the statusof the lake-basin system (LBS) have been found out, the factors that worsen the geo-ecological state in the lake and basin subsystems have been revealed,optimization measures in the objects of the nature reserve fund located within the natural reserve have been substantiated.The purpose of the studyis to determine the parameters of the structure of lake-basin landscapes (on the example of Zasvitske lake, Nobel National Natural Park, Ukraine), liminary and landscape-metric indicators of the geo-ecological status of the LBS and the factors influencing it as an information and analytical basis for ensuring the protection and management of the LBS located innature conservation area.The materials of the studywere the long-term field landscape-limnological and geo-ecological studies of the authors within the Polesia region of Ukraine and, in particular, the LBS of the Nobel National Nature Park.The research methodologywas based on complex physical-geographical methods, hydrological profil-ing and creation of bathymetric models of reservoirs, hydrochemical diagnostics of water masses of the lakes, geochemical analyses of bottom sediments, landscape mapping using GIS-technologies.The resultsof geo-ecological (landscape-ecological) researches of the lake-basin system of Zasvitske lake have been presented, in particular,original profiles and bathymetric model of the reservoir, landscape maps of the aqual complex and the lake catchment, limno-and landscape characteristics of the LBS have been shown. Considering the level of anthropogenic transformations of the LBS and the presence of a high proportion of ecologically-stabilizing lands (forests, reservoirs of natural origin), the level of sustainability of the LBS is estimated as high.An assessment of the hydrological characteristics of the reservoir and hydro-chemical characteristics allows to attribute this lake to an oligotrophic type. The results of a comprehensive analysis of the geo-ecological parameters of the state of Zasvitske lake and its landscape-limnological func-tioning indicate the expediencyof recreational specialization of nature management in the Nobel National Park, that includes this lake. Scientific novelty. The application of proposed landscape-basin approach and the algorithm of the LBS study increase the possibilities of functional zoning of national parks with high index of lakes, as well as solving the problems of nature protection and optimization of nature management. Practical importance. The created electronic landscape maps and the base of limnometric parameters can be used as reference documents for the certification and cadastral evaluation of the transboundary pro-tected areasof Ramsar type, geo-ecological monitoring and an integrated management of lakes by the basin approach in conditions of intense climate change

Quaternary interglacial sediments as possible natural sources of arsenic and molybdenum anomalies In stream sediments In Lithuania

Geochemical investigations were conducted on Quaternary interglacial sediments in order to reveal if they can be a natural source of 10 potentially harmful chemical elements: As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, V and Zn. Determination of the total contents of elements in 680 samples was performed by EDXRF analysis. The content of Ni, Cu, Pb, Ba in all analyzed samples was lower than maximum permissible concentrations (MPC) for soil, the content of Zn, V, Cr, Mn exceeded MPC values only in several samples (≤4%). The highest percentage of anomalous samples where MPC was exceeded was characteristic of Mo (21%) and As (12.6%). Therefore, interglacial sediments, especially enriched in organic matter and other sorbents, comprise one of the possible natural sources of Mo and As. It is probable that they contribute to As and Mo anomalies in stream sediments in Lithuania. First published online: 22 Dec 201

Relocated interglacial lacustrine sediments from an esker at Snickarekullen, S.W. Sweden

Lumps of diatom-rich, laminated sediments were discovered redeposited and interbedded in a Late Weichselian delta sequence in a small glaciofluvial esker at Snickarekullen, south-western Sweden. Radiocarbon dating of the sediments gave an infinite age (≫45 000 B.P.). The composition and sediment structure of the lumps were studied in epoxy-impregnated thin sections using SEM and EDS. Quantitative and qualitative diatom analyses of the sediments were carried out, as well as pollen and macrofossils analyses. The biostratigraphy is compared with that from Holsteinian interglacial sites in surrounding countries, the evidence for which is briefly reviewed. It is concluded that the sediments were deposited in the central part of a lake probably during different parts of the Holsteinian interglacial. The water body changed from a rather shallow lake with a high pH to a considerably deeper, oligotrophic lake with neutral to slightly acidic water during the sedimentation period. The local and regional vegetation developed from an open pine-birch forest into a much more closed vegetation of pine, spruce, larch, alder and hornbeam

Correlation of Eemian sections in Lithuania and Belarus based on palaeomagnetic, radioisotope and palaeobotanic data

Eemian (Murava, Merkinė deposits at five exposed sections (Zaslavl, Zhukevichi, Ponemun, Snaigupėlė, and Netiesos) located in Lithuania and Belarus are described. Preliminary palaeomagnetic results show a record of the Brunhes epoch normal magnetic field and a short-term reversal – the Blake Event – is recognized in three of the five sections. The Blake Event recorded in the Netiesos section is characterized by a pattern consisting of three short reversed polarity intervals separated by two short normal polarity intervals. The directional changes of declination, inclination, and MS (magnetic susceptibility) are clear. ESR dating (112.5 ±10.8 and 112.1 ±25.9) and 230Th/U dates obtained from this section (108.8 ±12.0/9.9 ka for the L/L technique and 100.2 ±10.3/8.6 ka for the TSD technique) suggest that (Blake and post-Blake) palaeomagnetic excursions are present in this section. Palaeobotanical analysis and isotope dating of the Netiesos section suggest that the Blake Event occurred during the climatic optimum