Diatom analyses were carried out on two sections: Vaitkūnai and Kūdre˙, representing the Early Pl... more Diatom analyses were carried out on two sections: Vaitkūnai and Kūdre˙, representing the Early Pleistocene Turgeliai Interglacial, and in one section, representing the Jononys sediments of the Bute˙nai (Holsteinian) Interglacial. Palaeoecological conditions during the deposition of these sediments were deduced from the changes in the freshwater diatom flora. The diatom assemblages show some similarity in composition to those of coeval interglacial sediments in Russia and Belorus (Jakubovskaya et al., 1991; Loginova, 1981).
Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynami... more Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynamics in deglaciated regions of northern and north eastern Europe, previously covered by the ice sheet of the Late Weichselian Glaciation. Therefore, the territory of Belarus, which stretches in the periglacial zone of the Last Glaciation and the most part of which was free of ice during the Last Glacial maximum, is off particular importance in analysing the postglacial floral establishment and the subsequent vegetation dynamics in this part of the continent. In this study, results of palaeobotanical (pollen and plant macrofossil), lithological (measurements of magnetic susceptibility, MS) and isotopic (14C) investigations were obtained to fill the existing gap in reconstructing the peculiarities of the terrestrial and aquatic vegetation dynamics throughout the Lateglacial - Early Holocene period in the central Belarus. The investigated sediment profile, comprising organically enriched gyttja at 13,400–13,100 cal yr BP, carbon enriched and sandy gyttja at 13,100–9700 cal yr BP and unconsolidated mud after 9500 cal yr BP, provides clear evidence proving the flourishing of a pine-birch predominated forest with occasional spruce stands during the Allerod in area. Three occasions of change in the vegetation structure were noted within the Younger Dryas, i.e. 12,900–12,700 cal yr BP, 12,200–12,000 cal yr BP and 11,900–11,700 cal yr BP, suggesting negative climatic excursion taken place in area and facilitating flourishing of a Picea-predominating forest that culminated at about 12,300 and 12,000 cal yr BP. Pollen record suggests the Early Holocene vegetation shifts occurring at about 11,300–11,200 cal yr BP, 10,800–10,600 cal yr BP and 10,300–10,100 cal yr BP evidence the general response to the global-scale climatic events i.e. Preborael Oscillation or “10,2 ka” while fluctuations triggered by local or regional-scale climatic events have been identified as well. About 10,800–10,700 cal yr BP, formation of the forest with an increasing representation of thermophilous taxa (Ulmus, Tilia, Quercus) started in area.
Abstract The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called ... more Abstract The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called Lithuanian Maritime Region (LMR) – a belt several tens of kilometres wide along the Baltic Sea coast – is characterised by a complicated Quaternary structure and many of unsolved problems related to stratigraphy and palaeogeography. The inter-till lacustrine sediments widespread in the middle part of the Pleistocene thickness play a key role in solving the mentioned problems. The primary inter-till sediments were attributed, as a single lithostratigraphic unit, to the late Saalian Glaciation (MIS 6, Pamarys Sub-Formation; according to the Lithuanian Quaternary Stratigraphic Scheme). Subsequent detailed investigations show that the investigated inter-till succession represents a more complicated sediment complex formed over a wide time interval from the Saalian ice sheet decay at the very end of MIS 6 to the beginning of severe climate cooling during MIS 4. This standpoint is confirmed by the results of a few series of OSL and IR-OSL datings of inter-till sediments, as well as by data of pollen and diatom analysis. The more detailed stratigraphic subdivision of the inter-till sedimentary complex offers a new significant insight into the regional stratigraphic scheme of the Quaternary. As a result of the mentioned investigations, a new original reconstruction of the palaeogeographic situation in the LMR during the MIS 6 – MIS 3 time span was carried out. The lowermost part of the investigated inter-till sediments, attributed to MIS 6, could be correlated with the third MIS 6 warming in Northern Eurasia about 155 ka ago. The reconstruction of the palaeoenvironmental changes starting from MIS 6 and lasting to MIS 3 shows that the Eemian Sea MIS 5e in age was absent in the LMR, while part of the south-eastern Baltic Sea region was covered by a continental ice sheet during MIS 4 and, possibly, the very beginning of MIS 3.
Abstract The Late Pleistocene and Early Holocene were time periods of significant transitions bet... more Abstract The Late Pleistocene and Early Holocene were time periods of significant transitions between glacial and warm climate states. In this contribution, a study of changes of diatom assemblage compositions in recurrence plots, rarefaction models, and their rank abundance distributions (Fisher's alpha) in the Southeast Baltic is presented. Three sites were studied for this purpose: Lake Kamyshovoye (Kaliningrad Region, Russia), Lake Kasuciai (W Lithuania), and Lake Petresiūnai (NE Lithuania). The recurrence plots revealed a compositionally stable interval at the end of the Pleistocene and a subsequent continuous and directional turnover (compositional trend) of local diatom communities throughout the Early Holocene. An analysis of rank abundance distributions and rarefaction analysis revealed a persistent long-term increase in the diversity of diatoms which started after the Younger Dryas cold episode; additional data suggest possible effects of the multi-centennial scale “9.3” Ka BP cold event. The close correlation between diatom diversity changes and geographically widespread climatic trends shows strong potential for this algae group in the regional analyses of climatic perturbations.
New data were obtained from the sedimentary sequence study of Lieporiai palaeolake, Northern Lith... more New data were obtained from the sedimentary sequence study of Lieporiai palaeolake, Northern Lithuania, employing a multi-proxy abiotic approach, for the description of the Lateglacial-Early Holocene palaeoenvironmental dynamics in the basin. The study reveals significant differences in sediments deposited in the Lateglacial, at the end of Lateglacial/Early Holocene and in the Late Holocene time periods. Six main environmental stages are described. After glacial retreat, the formed landscape was re-organized by very fast currents that might have appeared later than previously thought. Rapid water flow stabilized and lacustrine sedimentation began together with the appearance of scarce pioneer vegetation shortly before 14 600 cal yr BP, (GI-1e). The development of the lake with mostly undisturbed sedimentation continued up to the final stages of the Lateglacial Interstadial. The warm period caused maximum precipitation of Ca and Sr carbonates, which strongly affected sediment saturat...
ABSTRACT To reconstruct the Lateglacial and early Holocene palaeoenvironmental dynamics in the no... more ABSTRACT To reconstruct the Lateglacial and early Holocene palaeoenvironmental dynamics in the northern part of Lithuania, the sediment record from Ginkūnai Lake was studied applying a multi-proxy approach, involving pollen, diatom, and plant macrofossil surveys as well as δ18O, δ13C, 14C and loss on ignition (LOI) measurements, together with geochemical investigations. The obtained data suggest the deglaciation of the area started at approximately 16,000–16,500 cal BP, followed by the formation of a tree-less tundra. The obtained palaeobotanical records indicate the scarcity of the vegetation cover and the flourishing of the non-arboreal taxa in the local flora, suggesting a severe climatic regime. After 13,700 cal BP, the Pinus-Betula predominating forest progressively expanded, although this process was partly reversed during the recurrence of a cold interval recorded from 13,000 to 13,100 cal BP. Since 12,600 cal BP, rapid aridification of the climatic regime reflected in the isotope record was accompanied by the formation of cold-adapted vegetation, including Picea stands, which acted as an intensive supply of allochthonous material into the basin, thereby decreasing the water level. The identified period of physical disturbance lasted until approximately 11,800 cal BP. Significant changes of the palaeoenvironmental regime subsequently occurred in the area and were manifested in most of the obtained proxies, i.e., changes in the sediment type, transformations of the vegetation cover, and fluctuations of the sedimentation regime. Isotope records along with the geochemical data indicate a major climatic turn in terms of the temperature and moisture after 11,500 cal BP. The rising productivity of the basin was coincident with the stabilisation of the soil layer and the formation of dense vegetation cover enriched by Corylus (ca 9800 cal BP) and Ulmus (ca 10,300 cal BP) during the early Holocene. After 10,800 cal BP, the investigated part of the basin changed to a peat bog.
As part of a teaching course, palaeoecological investigation of Holocene organic sediments at Joh... more As part of a teaching course, palaeoecological investigation of Holocene organic sediments at Johvikasoo on the island of Saaremaa, were made using standard techniques including diatom, macrofossil and pollen analyses, and radiocarbon dating. The basin development, changes in vegetation and flora and nature of human impact on the vegetation are discussed. Sudden openings in the local forest vegetation coincide with wetter conditions, more charcoal dust and the presence of apophytic and anthropogenic plant species. The local immigration of Picea is dated to around 4000-3500 BP.
The lithostratigraphy and diatom flora of Pleistocene deposits from the Utena region in eastern L... more The lithostratigraphy and diatom flora of Pleistocene deposits from the Utena region in eastern Lithuania have been investigated. A statistical treatment of the till pebble petrographic data was carried out and a subdivision of the Pleistocene sequences into horizons was made on the basis of the bedrock composition. Diatom complexes from different interglacials were investigated in order to obtain a stratigraphic criterion and to clarify the nature of the palaeoenvironment during sedimentation. Freshwater diatoms Cyclotella radiosa var. lichvinensis (Jouse) Log., Aulacoseira granulata f. curvata and A. italica f. curvata typical of the Holsteinian Interglacial were identified. The stratigraphical subdivision of the Lower Pleistocene sequences was most problematical and needs further detailed studies.
Diatom analyses were carried out on two sections: Vaitkūnai and Kūdre˙, representing the Early Pl... more Diatom analyses were carried out on two sections: Vaitkūnai and Kūdre˙, representing the Early Pleistocene Turgeliai Interglacial, and in one section, representing the Jononys sediments of the Bute˙nai (Holsteinian) Interglacial. Palaeoecological conditions during the deposition of these sediments were deduced from the changes in the freshwater diatom flora. The diatom assemblages show some similarity in composition to those of coeval interglacial sediments in Russia and Belorus (Jakubovskaya et al., 1991; Loginova, 1981).
Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynami... more Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynamics in deglaciated regions of northern and north eastern Europe, previously covered by the ice sheet of the Late Weichselian Glaciation. Therefore, the territory of Belarus, which stretches in the periglacial zone of the Last Glaciation and the most part of which was free of ice during the Last Glacial maximum, is off particular importance in analysing the postglacial floral establishment and the subsequent vegetation dynamics in this part of the continent. In this study, results of palaeobotanical (pollen and plant macrofossil), lithological (measurements of magnetic susceptibility, MS) and isotopic (14C) investigations were obtained to fill the existing gap in reconstructing the peculiarities of the terrestrial and aquatic vegetation dynamics throughout the Lateglacial - Early Holocene period in the central Belarus. The investigated sediment profile, comprising organically enriched gyttja at 13,400–13,100 cal yr BP, carbon enriched and sandy gyttja at 13,100–9700 cal yr BP and unconsolidated mud after 9500 cal yr BP, provides clear evidence proving the flourishing of a pine-birch predominated forest with occasional spruce stands during the Allerod in area. Three occasions of change in the vegetation structure were noted within the Younger Dryas, i.e. 12,900–12,700 cal yr BP, 12,200–12,000 cal yr BP and 11,900–11,700 cal yr BP, suggesting negative climatic excursion taken place in area and facilitating flourishing of a Picea-predominating forest that culminated at about 12,300 and 12,000 cal yr BP. Pollen record suggests the Early Holocene vegetation shifts occurring at about 11,300–11,200 cal yr BP, 10,800–10,600 cal yr BP and 10,300–10,100 cal yr BP evidence the general response to the global-scale climatic events i.e. Preborael Oscillation or “10,2 ka” while fluctuations triggered by local or regional-scale climatic events have been identified as well. About 10,800–10,700 cal yr BP, formation of the forest with an increasing representation of thermophilous taxa (Ulmus, Tilia, Quercus) started in area.
Abstract The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called ... more Abstract The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called Lithuanian Maritime Region (LMR) – a belt several tens of kilometres wide along the Baltic Sea coast – is characterised by a complicated Quaternary structure and many of unsolved problems related to stratigraphy and palaeogeography. The inter-till lacustrine sediments widespread in the middle part of the Pleistocene thickness play a key role in solving the mentioned problems. The primary inter-till sediments were attributed, as a single lithostratigraphic unit, to the late Saalian Glaciation (MIS 6, Pamarys Sub-Formation; according to the Lithuanian Quaternary Stratigraphic Scheme). Subsequent detailed investigations show that the investigated inter-till succession represents a more complicated sediment complex formed over a wide time interval from the Saalian ice sheet decay at the very end of MIS 6 to the beginning of severe climate cooling during MIS 4. This standpoint is confirmed by the results of a few series of OSL and IR-OSL datings of inter-till sediments, as well as by data of pollen and diatom analysis. The more detailed stratigraphic subdivision of the inter-till sedimentary complex offers a new significant insight into the regional stratigraphic scheme of the Quaternary. As a result of the mentioned investigations, a new original reconstruction of the palaeogeographic situation in the LMR during the MIS 6 – MIS 3 time span was carried out. The lowermost part of the investigated inter-till sediments, attributed to MIS 6, could be correlated with the third MIS 6 warming in Northern Eurasia about 155 ka ago. The reconstruction of the palaeoenvironmental changes starting from MIS 6 and lasting to MIS 3 shows that the Eemian Sea MIS 5e in age was absent in the LMR, while part of the south-eastern Baltic Sea region was covered by a continental ice sheet during MIS 4 and, possibly, the very beginning of MIS 3.
Abstract The Late Pleistocene and Early Holocene were time periods of significant transitions bet... more Abstract The Late Pleistocene and Early Holocene were time periods of significant transitions between glacial and warm climate states. In this contribution, a study of changes of diatom assemblage compositions in recurrence plots, rarefaction models, and their rank abundance distributions (Fisher's alpha) in the Southeast Baltic is presented. Three sites were studied for this purpose: Lake Kamyshovoye (Kaliningrad Region, Russia), Lake Kasuciai (W Lithuania), and Lake Petresiūnai (NE Lithuania). The recurrence plots revealed a compositionally stable interval at the end of the Pleistocene and a subsequent continuous and directional turnover (compositional trend) of local diatom communities throughout the Early Holocene. An analysis of rank abundance distributions and rarefaction analysis revealed a persistent long-term increase in the diversity of diatoms which started after the Younger Dryas cold episode; additional data suggest possible effects of the multi-centennial scale “9.3” Ka BP cold event. The close correlation between diatom diversity changes and geographically widespread climatic trends shows strong potential for this algae group in the regional analyses of climatic perturbations.
New data were obtained from the sedimentary sequence study of Lieporiai palaeolake, Northern Lith... more New data were obtained from the sedimentary sequence study of Lieporiai palaeolake, Northern Lithuania, employing a multi-proxy abiotic approach, for the description of the Lateglacial-Early Holocene palaeoenvironmental dynamics in the basin. The study reveals significant differences in sediments deposited in the Lateglacial, at the end of Lateglacial/Early Holocene and in the Late Holocene time periods. Six main environmental stages are described. After glacial retreat, the formed landscape was re-organized by very fast currents that might have appeared later than previously thought. Rapid water flow stabilized and lacustrine sedimentation began together with the appearance of scarce pioneer vegetation shortly before 14 600 cal yr BP, (GI-1e). The development of the lake with mostly undisturbed sedimentation continued up to the final stages of the Lateglacial Interstadial. The warm period caused maximum precipitation of Ca and Sr carbonates, which strongly affected sediment saturat...
ABSTRACT To reconstruct the Lateglacial and early Holocene palaeoenvironmental dynamics in the no... more ABSTRACT To reconstruct the Lateglacial and early Holocene palaeoenvironmental dynamics in the northern part of Lithuania, the sediment record from Ginkūnai Lake was studied applying a multi-proxy approach, involving pollen, diatom, and plant macrofossil surveys as well as δ18O, δ13C, 14C and loss on ignition (LOI) measurements, together with geochemical investigations. The obtained data suggest the deglaciation of the area started at approximately 16,000–16,500 cal BP, followed by the formation of a tree-less tundra. The obtained palaeobotanical records indicate the scarcity of the vegetation cover and the flourishing of the non-arboreal taxa in the local flora, suggesting a severe climatic regime. After 13,700 cal BP, the Pinus-Betula predominating forest progressively expanded, although this process was partly reversed during the recurrence of a cold interval recorded from 13,000 to 13,100 cal BP. Since 12,600 cal BP, rapid aridification of the climatic regime reflected in the isotope record was accompanied by the formation of cold-adapted vegetation, including Picea stands, which acted as an intensive supply of allochthonous material into the basin, thereby decreasing the water level. The identified period of physical disturbance lasted until approximately 11,800 cal BP. Significant changes of the palaeoenvironmental regime subsequently occurred in the area and were manifested in most of the obtained proxies, i.e., changes in the sediment type, transformations of the vegetation cover, and fluctuations of the sedimentation regime. Isotope records along with the geochemical data indicate a major climatic turn in terms of the temperature and moisture after 11,500 cal BP. The rising productivity of the basin was coincident with the stabilisation of the soil layer and the formation of dense vegetation cover enriched by Corylus (ca 9800 cal BP) and Ulmus (ca 10,300 cal BP) during the early Holocene. After 10,800 cal BP, the investigated part of the basin changed to a peat bog.
As part of a teaching course, palaeoecological investigation of Holocene organic sediments at Joh... more As part of a teaching course, palaeoecological investigation of Holocene organic sediments at Johvikasoo on the island of Saaremaa, were made using standard techniques including diatom, macrofossil and pollen analyses, and radiocarbon dating. The basin development, changes in vegetation and flora and nature of human impact on the vegetation are discussed. Sudden openings in the local forest vegetation coincide with wetter conditions, more charcoal dust and the presence of apophytic and anthropogenic plant species. The local immigration of Picea is dated to around 4000-3500 BP.
The lithostratigraphy and diatom flora of Pleistocene deposits from the Utena region in eastern L... more The lithostratigraphy and diatom flora of Pleistocene deposits from the Utena region in eastern Lithuania have been investigated. A statistical treatment of the till pebble petrographic data was carried out and a subdivision of the Pleistocene sequences into horizons was made on the basis of the bedrock composition. Diatom complexes from different interglacials were investigated in order to obtain a stratigraphic criterion and to clarify the nature of the palaeoenvironment during sedimentation. Freshwater diatoms Cyclotella radiosa var. lichvinensis (Jouse) Log., Aulacoseira granulata f. curvata and A. italica f. curvata typical of the Holsteinian Interglacial were identified. The stratigraphical subdivision of the Lower Pleistocene sequences was most problematical and needs further detailed studies.
Uploads