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Showing papers in "Estonian Journal of Earth Sciences in 2010"


Journal ArticleDOI
TL;DR: In this article, the wave properties in the Baltic Sea and their seasonal variations are estimated by the use of a high-resolution version of the wave model, WAM, driven by adjusted geostrophic winds for 1970–2007 under ice-free conditions.
Abstract: The basic features of wave properties in the Baltic Sea and their seasonal variations are estimated by the use of a highresolution version (3 miles) of the wave model, WAM, driven by adjusted geostrophic winds for 1970–2007 under ice-free conditions. The model qualitatively reproduces the time series of the sea state and adequately replicates the seasonal patterns of wave intensity and the probability distribution functions for different wave heights in both offshore and coastal regions of the northern Baltic Proper and the Gulf of Finland. The areas of the largest overall wave activity are located in the eastern parts of the Bothnian Sea and northern Baltic Proper, south of Gotland, and in the Arkona Basin. The windiest season (September–February) and the time with the largest measured or modelled wave activity (October–March) occur with a time lag of 0.5–2 months.

55 citations


Journal ArticleDOI
TL;DR: In this article, an integrated study of the uppermost Ordovician Porkuni Stage in the Stirnas-18 core, western Latvia, has revealed one of the most complete Hirnantian successions in the eastern Baltic region.
Abstract: Integrated study of the uppermost Ordovician Porkuni Stage in the Stirnas-18 core, western Latvia, has revealed one of the most complete Hirnantian successions in the eastern Baltic region. The interval is characterized by two shallowing upwards depositional sequences that correspond to the Kuldiga and Saldus formations. The whole-rock carbon stable isotope curve indicates a long rising segment of the Hirnantian carbon isotope excursion, with the highest peak in the upper part of the Kuldiga Formation. The bioclast carbon and oxygen curves fit well with the whole-rock carbon data. Microand macrofossil data enabled seven combined associations to be distinguished within the Hirnantian strata. The early Porkuni fauna of the Spinachitina taugourdeaui Biozone, with pre-Hirnantian affinities, is succeeded by an interval with a Hindella–Cliftonia brachiopod association, a specific polychaete fauna, the chitinozoan Conochitina scabra, and the conodont Noixodontus girardeauensis. The middle part of the Kuldiga Formation is characterized by a low-diversity Dalmanella testudinaria brachiopod association, high diversity of scolecodonts, and the occurrence of the chitinozoan Lagenochitina prussica. From the middle part of the Kuldiga Formation the youngest occurrence yet known of the conodont Amorphognathus ordovicicus is reported. Also typical of the Kuldiga Formation is the occurrence of the trilobite Mucronaspis mucronata. The uppermost Hirnantian Saldus Formation contains no shelly fauna, but yields redeposited conodonts and at least partly indigenous chitinozoans and scolecodonts. Palaeontological criteria and stable isotope data enable correlation of the Stirnas section with other Hirnantian successions in the Baltic region and elsewhere.

48 citations


Journal ArticleDOI
TL;DR: Sediment cores from six lakes in northern, central, and southern Belarus were analyzed to establish correlations between changes in lake conditions and catchment evolution since the Older Dryas as discussed by the authors.
Abstract: Sediment cores from six lakes in northern, central, and southern Belarus were eхamined to establish correlations between changes in lake conditions and catchment evolution since the Older Dryas. Detailed studies were conducted in three areas with highly different landscape development history. Common patterns and synchronism in lake sedimentation and fluctuations are more diverse during the Late Glacial and early Holocene, mainly due to the general tendency of climate warming at the beginning of the postglacial epoch and disappearance of permafrost, which led to the increase in infiltrating processes. During the latter half of the Holocene lake level changes were asynchronous in different regions of Belarus. At that time most of the existing differences were caused by local factors.

38 citations


Journal ArticleDOI
TL;DR: In this paper, the authors synthesize marine and terrestrial records spanning the Brunhes Chron (0-780 000 years) using data from palaeoshelf, glacial, periglacial, and extraglacial zones of Northern Eurasia.
Abstract: Marine and terrestrial records spanning the Brunhes Chron (0-780 000 years) were synthesized using data from palaeoshelf, glacial, periglacial, and extraglacial zones of Northern Eurasia. The chronostratigraphic position of the identified palaeoenvironmental events and respective horizons in the composite chronostratigraphic column were established on the basis of electron spin resonance analysis of subfossil mollusc shells collected from marine, freshwater, and terrestrial deposits. Environ- ment and vegetation evolution during this period is characterized by pollen data from a series of spaced-apart reference sections on the East European Plain. The climate-chronostratigraphic record displays a sequence of eight intervals (the Holocene included) of warm climate and sea level highstand when marine sedimentation occurred on North Eurasian palaeo-shelves, and seven glacial epochs. A clear agreement between long pollen records and reliably dated warm-climate-related deposits was established for at least the last 600 000 years (from marine isotope stages 15 to 1). When integrated, these records have a potential of assigning warm/cold-climate-related deposits to the chronostratigraphically-organized sequence of the middle and late Quaternary palaeoenvironmental events.

27 citations


Journal ArticleDOI
TL;DR: In this paper, the spatial structure of wind patterns over the Gulf of Finland in the NE part of the Baltic Sea is analyzed on the basis of wind parameters measured at two lighthouses (Tallinnamadal near the southern coast of the gulf and Kalbadagrund near its northern coast), which are compared with the High Resolution Limited Area Model (HIRLAM) 6.4.
Abstract: . Several features of the spatial structure of wind patterns over the Gulf of Finland in the NE part of the Baltic Sea are analysed on the basis of wind parameters measured at two lighthouses (Tallinnamadal near the southern coast of the gulf and Kalbadagrund near its northern coast), which are compared with the High Resolution Limited Area Model (HIRLAM) 6.4.0 outputs for the period of April 2007ŒMarch 2008. It is shown that both the average air flow and the wind direction turn considerably clockwise when the air masses cross the gulf obliquely. Consequently, the influence of the Estonian mainland on the wind properties over the Gulf of Finland extends at least to a distance of 20 km to the Tallinnamadal Lighthouse area but hardly reaches a distance of 60 km where Kalbadagrund is located. The HIRLAM model captures well the wind direction at Tallinna-madal, whereas at Kalbadagrund the modelled wind direction is turned by > 20° counter-clockwise from the measured direction. The HIRLAM output matches well the wind speed at Kalbadagrund, but underestimates it at Tallinnamadal by more than 1 m/s.

25 citations


Journal ArticleDOI
TL;DR: In this article, an investigation of the late glacial Solova (Remmeski) basin, based on plant macrofossil and diatom record, AMS 14C chronology and sediment composition (loss-on-ignition and magnetic susceptibility data), provided information on vegetation history and palaeoenvironmental changes since the time of the deglaciation of the area around 14 000 cal yr BP.
Abstract: Reinvestigation of the late glacial Solova (Remmeski) basin, based on plant macrofossil and diatom record, AMS 14C chronology and sediment composition (loss-on-ignition and magnetic susceptibility data), provided information on vegetation history and palaeoenvironmental and palaeoclimatic changes since the time of the deglaciation of the area around 14 000 cal yr BP. The chronology of the sequence is based on seven AMS dates on terrestrial macrofossils, providing evidence of rapid sedimentation in between 14 000 and 13 500 cal yr BP. Loss-onignition data show a clear short-lived warming episode centred to 13 800 cal yr BP, tentatively correlated with the GI-1c warming of the event stratigraphy of the Last Termination in the North Atlantic region, which suggests that at least parts of the Haanja Heights were ice-free by 14 000 cal yr BP. Macrofossil evidence indicates Betula nana-Dryas octopetala-dominated open tundra communities with Saxifraga on dry ground, and Carex sp. and Juncus on wet ground at that time. The first evidence of the postglacial presence of tree birch (Betula pendula) in Estonia is dated back to 13 500 cal yr BP. However, conifer remains were not found in the late glacial sediment sequence of Solova Bog. The late-Allerod (GI-1a) organic deposits, which are quite typical of other parts of Estonia and indicate general warming, are missing at Solova, most probably due to a hiatus in sedimentation in this very small and shallow upland basin.

25 citations


Journal ArticleDOI
TL;DR: Palaeobotanical investigations were carried out with the aim of reconstructing the development of palaeovegetation and formation of sediments in the northeastern area of ancient Lake Burtnieks as discussed by the authors.
Abstract: Palaeobotanical investigations were carried out with the aim of reconstructing the development of palaeovegetation and formation of sediments in the northeastern area of ancient Lake Burtnieks. Pollen and plant macroremain studies provide information on vegetation development in the surroundings of the lake, including Stone Age settlements of Brauksas Ⅰ and Brauksas Ⅱ. Results of the investigations indicate that the development of vegetation together with sedimentation conditions in the palaeolake have changed since the Younger Dryas until today. Vegetation composition varies in different parts of the ancient Lake Burtnieks area due to past changes in lake water level which reached different sites at different times. Data from the northern part of ancient Lake Burtnieks indicate its gradual overgrowing since the Preboreal. Deposition of minerogenic lacustrine sediments (silt, clayey silt and sand) lasted until the Boreal or the Atlantic time, depending on the water depth of the lake locality. Clastic sediments were overlain by gyttja, which in turn was later covered by well-decomposed fen (sedge, sedge-grass) peat that started to form at the end of Atlantic time. Pollen and plant macroremain composition of lacustrine sediments and fen peat sequences suggests that people have inhabited the area since Preboreal-Boreal times. However, weak traces of possible presence of people are found already at the very end of the Younger Dryas. Fluctuating curves of broadleaved tree pollen, a significant amount of pollen of cultivated plants and charcoal dust in sediments indicate activities of an early man and refer to start of crop growing in the area in the second half of the Atlantic chronozone.

24 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used the 3D hydrodynamic Princeton Ocean Model as a tool to simulate the water circulation and the temperature distribution under the ice in Lake Paajarvi, Finland, showing a stable temperature field where a heat gain through the bottom and a heat loss through the ice nearly balance each other.
Abstract: In deep ice-covered lakes with temperatures below 4 °C the heat flux from the bottom sediment results in a horizontal density gradient and a consequent flow along the bottom slope. Measurements in Lake Paajarvi, Finland, show a stable temperature field where a heat gain through the bottom and a heat loss through the ice nearly balance each other. The circulation is thermal with low velocities (less than 1.5 cm s -1 ). We used the 3D hydrodynamic Princeton Ocean Model as a tool to simulate the water circulation and the temperature distribution under the ice. The model forcing was based on field temperature measurements. The model simulations suggest that in midwinter the velocity field of the upper water layers is anticyclonic while that of deep layers is cyclonic. Comparison with current measurements at one site showed good agreement between the modelled and observed results. On the basis of the modelled results it is possible to better understand the distributions of some micro- organisms and the accumulation of oxygen depleted waters in the deepest part of the lake.

21 citations


Journal ArticleDOI
TL;DR: The information obtained from a 21 m thick open-pit section of silty-clayey sediments in the Arumetsa bedrock valley, southwestern Estonia, revealed that lacustrine to glaciolacustrine sedimentation at the site started prior to 151 ka ago and lasted to about the end of marine isotope stage 6 (MIS6) at 130 ka as mentioned in this paper.
Abstract: The information obtained from a 21 m thick open-pit section of silty-clayey sediments in the Arumetsa bedrock valley, southwestern Estonia, revealed that lacustrine to glaciolacustrine sedimentation at the site started prior to 151 ka ago and lasted to about the end of marine isotope stage 6 (MIS6) at 130 ka. Further down from the 151 ka age-level to the bottom of the buried valley there are ca 60 m of lacustrine fine-grained sediments, the age of which remains still unclear. The Late Saalian sediments at Arumetsa are discordantly overlain by Middle Weichselian clay, silt and sand, deposited between ca 44 and 37 ka ago. As testified by optically stimulated luminescence (OSL) ages, and pollen and diatom record, the Middle Weichselian fine-grained sediments contain redeposited Holsteinian but no Eemian pollen, and have not been fully bleached during deposition. Chronological, microfossil and sedimentological data show two hiatuses in the Arumetsa section. The first hiatus has left no sedimentary evidence for the period between ca 130 ka and 44 ka ago (MIS5 to older half of MIS3). The younger hiatus from ca 37 to 22 ka occurs between the Middle Weichselian lacustrine silt and the Late Weichselian till layer on top of the section.

18 citations


Journal ArticleDOI
TL;DR: In this article, the authors discuss the importance of human-human interaction in the context of cyber-physical learning and propose an approach to improve the human-computer interaction, which they call human-machine interaction.
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16 citations


Journal ArticleDOI
TL;DR: In this article, the possibilities of using High Resolution Limited Area Model (HIRLAM) version 6.4.0 outputs to describe wind parameters in the coastal zone of Estonia were investigated.
Abstract: The possibilities of using High Resolution Limited Area Model (HIRLAM) version 6.4.0 outputs to describe wind parameters in the coastal zone of Estonia were investigated. For this purpose output from 3-dimensional variational (3DVAR) analysis and 24 h forecast files were compared with measurements at nine coastal sites during January and April-December 2007. Special attention was paid to moderate and strong winds (wind speed > 5 m/s) that are responsible for sea level changes and high wave heights in the coastal area. It is shown that HIRLAM overestimates the wind speed. This overestimation is stronger in cases where HIRLAM uses an inadequate land-sea fraction in the respective cells. The model describes the angular distribution of moderate and strong winds better than that of weak winds. Except for one station, approximately 90% of HIRLAM estimates of the direction of moderate and strong winds differ less than ± 22.5° from the measured values; in approximately 60% of cases the direction differs less than ± 10°. The HIRLAM system approximates best the winds at the westernmost stations on the Estonian islands and in Parnu, whereas a 24 h forecast gives somewhat better results than the winds diagnosed from 3DVAR analysis.

Journal ArticleDOI
TL;DR: In this paper, a ground water flow and transport model of the Kopli Peninsula was built to investigate the upconing of saline water from an underlying layer, due to overexploitation of groundwater.
Abstract: The Cambrian-Vendian aquifer system is the most exploited groundwater resource in northern Estonia. As a result, the extensive use of groundwater has caused changes in the direction and velocity of groundwater flow in the Tallinn area. A ground- water flow and transport model of the Kopli Peninsula was built to investigate the upconing of saline water from an underlying layer, due to overexploitation of groundwater. A transient flow model was run in different flow regimes, using the pumping and water head data from the years 1946-2007. The vertical conductivity of crystalline rocks and the lower portion of Cambrian- Vendian rocks was found to be of the greatest importance for the range and shape of upconing phenomena. The results of the current study show that the range of the upconing process is dependent on the depth of the well screen interval. Therefore the results of many previous studies can be biased by the leaking of water from the underlying crystalline basement. The results also suggest that leakage from an underlying layer can be minimized by changing the screen depth of production wells.

Journal ArticleDOI
TL;DR: In this article, the distribution, morphology, fillings, and origin of buried valleys are discussed, and the direction of the valleys varies from NW to NE. And the Tallinn valley with its tributary valleys (Saku and Sausti) and fore-klint branches (Harku, Lillekula, and Kadriorg) looks like a river system.
Abstract: The distribution, morphology, fillings, and origin of buried valleys are discussed. The direction of the valleys varies from NW to NE. Within the Viru-Harju Plateau the valleys have a more or less symmetric profile, but asymmetric profiles are dominating in the pre-klint area. They are mainly filled with glacial (till), glaciofluvial (sand, gravel, and pebbles), glaciolacustrine (varved clay), and marine (fine-grained sand) deposits. The Tallinn valley with its tributary valleys (Saku and Sausti) and fore- klint branches (Harku, Lillekula, and Kadriorg) looks like a river system. The fore-klint branches extend over 20 km in the Gulf of Finland. They are probably tributaries of the ancient river Pra-Neva. Most likely, the formation of valleys was continuous, starting from pre-Quaternary river erosion, and was sculptured by variable processes during the ice ages and influenced by flowing water during the interglacial periods.

Journal ArticleDOI
TL;DR: In this article, a diamicton-stratified sand deposit has been studied in the Veskoniemi area, near Lake Inarijarvi in central Finnish Lapland.
Abstract: The stratigraphy and sedimentology of a diamicton-stratified sand deposit have been studied in the Veskoniemi area, near Lake Inarijarvi in central Finnish Lapland. Test pit excavations were used for stratigraphical investigations. Till-covered laminar and crossbedded sands were dated using optically stimulated luminescence (OSL). Ages range between 21.0 ± 1.5 and 22.4 ± 1.6 ka for laminated sands at upper levels and 39 ± 3 and 46 ± 3 ka for sands at deeper levels. These dating results strengthen the evidence for a Middle Weichselian interstadial in northern Finland during oxygen isotope stage 3, and can be compared with other results in eastern and southern Lapland. This is the first time that sediments from the Middle and Late Weichselian contact have been identified in Finland. These new dating results indicate that an ice-free period could have lasted from halfway through the Middle Weichselian to the beginning of the Late Weichselian about 22-25 ka ago in northern Finland.

Journal ArticleDOI
TL;DR: In this paper, the authors propose a new approach to deal with the problem of gender discrimination in the context of health care, which they call "gender parity" (GSH), where the goal is to improve the health of women.
Abstract: ��������� ���� ��������� �������� ��������� ��������� ����� ����� ��������� ����� �������� ������� ������ ����� ����� �������� ������ ������� ������� ����� ����� ��������� ����� ����� ������� ��������� ������ ��������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� � �� �� �� ��� ��� ��� ��� ��� ��� ��� �������� ����� ����� ������� ������� ������� ������ ����� ������� ����� ������� ����� ����� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� � ����� � � ������� � ����� ������ ������� ����� ����� ��������� ����� ������� ������� ����� ����� ������� ������ ������ ���� ��� ����������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� � ��� ��� ��� ��� ��� �������� ���������� ��� ���� � ��������������� � ��������� ������� ������ � ������� ��� ��� � � � � � ����������� ������ ��������� �������� ���������� ���������� ������ ����� �������� ������ ������ � � � � � � �� � � � � �� � � � � �� ������ � ������ � � � ������ ����������� �������� �� �� � ��� � ��� : ����������������� ��������� �������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� � � �������� ������� ������ ��� ����� ����� ��������� ����� ������� ������� ����� ������� ������ � ������ � � � � � � � � � � � � ������ ����� ����� ������� ������� ����� ������ ������� ����� ����� ��������� ���������� ��������� ������� ����� ������ ������� ���������� ������ � � � � � � ����� � ������ ������� � ������ ������ ���������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ���� ��� ��� ��� ��� ��� ��� ��� �������� ������ ����������� ������ ���������� ���������� �������� ����������� ���������� ����� �������������� ���������� ���� ���� ���� ���� ���� ���� ���� ��� ��� ��� ��� ������� ����������� ����� ��������� ������� ������������� ������ ����� ������� ����� ����� ������� ���������� ���� ��� � ������ � � � � � �������� �������� ������ ������ �������� � � � � � � � � � � � � � � � � � � � ���� ���� ���� ���� ���� � � � � � � ������ ������ � ������ ��������� � � � � � � � � � � � ���������� ���� � ´ ´ ´

Journal ArticleDOI
TL;DR: In this article, a U-Pb dating of titanite from an augen granitoid mylonite in the Druksiai-Polotsk Deformation Zone has yielded a concordant age of 1534 +/- 9 Ma.
Abstract: A U-Pb dating of titanite from an augen granitoid mylonite in the Druksiai-Polotsk Deformation Zone has yielded a concordant age of 1534 +/- 9 Ma. This light brown titanite follows the foliation in the host rock and was obviously formed during retrogression from amphibolite to epidote-amphibolite facies and coeval mylonitization. Shear zones of the same age are known in southern and central Sweden and in NE Poland. These E-W trending deformation zones accommodate both mafic and granitoid intrusions and are probably related to an extensional period in the Mesoproterozoic evolution in the western part of the East European Craton prior to the 1.50-1.45 Ga Danopolonian orogeny.

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TL;DR: Characteristics of the morphology, sculpture and ultrasculpture of these small ossicles that could be useful as additional features in taxonomy and systematics are revealed, in a manner similar to their use in fossil material.
Abstract: Small to very small bones (ossicles) in one species each of the families Cyclopteridae and Liparidae (Cottiformes) of the Baltic Sea are described and for the first time illustrated with SEM images. These ossicles, mostly of dermal origin, include dermal platelets, scutes, tubercles, prickles and sensory line segments. This work was undertaken to reveal characteristics of the morphology, sculpture and ultrasculpture of these small ossicles that could be useful as additional features in taxonomy and systematics, in a manner similar to their use in fossil material. The scutes and tubercles of the cyclopterid Cyclopterus lumpus Linnaeus are built of small denticles, each having its own cavity viscerally. The thumbtack prickles of the liparid Liparis liparis (Linnaeus) have a tiny spinule on a porous basal plate; the small size of the prickles seems to be related to their occurrence in the exceptionally thin skin, to an adaptation for minimizing weight and/or metabolic cost and possibly to their evolution from isolated ctenii no longer attached to the scale plates of ctenoid scales. Nodular ultrasculpture was found on the tubercle denticles of C. lumpus, resembling some kinds of ultrasculpture seen in Palaeozoic vertebrates. Samples from the posterior part of the head of C. lumpus and the anterior part of the trunk of L. liparis each contained an ossified sensory line segment with distinct characteristics, as also reported in other cottoids.

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TL;DR: The Varangu section is located on the southern slope of the Pandivere Upland in northern Estonia as discussed by the authors, and a silty clay bed formed in the study area at 11 200–9300 cal yr BP, according to ostracod subfossils (e.g. Tonnacypris estonica, Leucocythere mirabilis, Limnocytherina sanctipatricii).
Abstract: The Varangu section is located on the southern slope of the Pandivere Upland in northern Estonia. A silty clay bed formed in the study area at 11 200–9300 cal yr BP, according to ostracod subfossils (e.g. Tonnacypris estonica, Leucocythere mirabilis, Limnocytherina sanctipatricii) in an oxygen-rich cool and oligotrophic profundal lacustrine environment, with an inflow of surface waters through springs. The record of specific ostracods (e.g. Cyclocypris ovum, Cypridopsis vidua, Metacypris cordata) reflects littoral environments, ongoing eutrophication, temperature increase and a progressive shallowing of the lake in the early Holocene (9300–7400 cal yr BP) when the tufa bed accumulated. A slight cooling and productivity decrease at 9100– 8600 cal yr BP preceded further temperature rise and water level lowering, leading to the development of a eutrophic lake and cease of tufa precipitation (8600–7400 cal yr BP).

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TL;DR: Small to very small ossified structures (ossicles) such as cephalic horns, dermal tubercles, fin-ray rods, lateral-line canal segments, branchial tooth plates and gill-raker tubercles of three species of the teleostean fish family Cottidae inhabiting the Baltic Sea are described and for the first time illustrated with SEM images, with emphasis on their microscopic external features.
Abstract: Small to very small ossified structures (ossicles) such as cephalic horns, dermal tubercles, fin-ray rods, lateral-line canal segments, branchial tooth plates and gill-raker tubercles of three species of the teleostean fish family Cottidae inhabiting the Baltic Sea are described and for the first time illustrated with SEM images, with emphasis on their microscopic external features. The morphology and sculpture of these small ossicles notably differ in the three genera, but differences can also occur between males and females, as documented here in Myoxocephalus scorpius (Linnaeus). The detailed features of such ossicles are potentially useful for taxonomic identification in sea-floor sediments or gut contents, in a manner similar to their use in many modern and fossil fishes, and may also prove useful as phylogenetically important characters at generic and familial levels.

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TL;DR: In this paper, the authors present a palaeogeographical map of the Tallinn area during different stages of the Baltic Sea in the vicinity of Tallinn, showing that during the Ancylus Lake transgression about 10 300 cal yr BP the highest coastline at 34–36 m a.s.l. broadly outlined the klint escarpment.
Abstract: The Tallinn area was recovered from the Weichselian ice sheet not later than 13 000–12 800 cal yr BP but remained for ca 1500 years under the waters of the Baltic Ice Lake (BIL). The highest parts of Tallinn emerged from the BIL after its drainage about 11 600 cal yr BP. At the beginning of the Yoldia Sea stage the present city area was submerged by sea water, except for the highest parts of Viimsi, Lasnamäe and Nõmme. At the end of the Yoldia Sea stage the Ülemiste, Pääsküla and Männiku basins isolated from the sea. During the Ancylus Lake transgression about 10 300 cal yr BP the highest coastline at 34–36 m a.s.l. broadly outlined the klint escarpment. The Litorina Sea transgressional coastline at 7800–7600 cal yr BP and beach formations at 21–22 m a.s.l. are less developed than the Ancylus ones and often covered by aeolian deposits. Toompea arched north as a cape in the Litorina Sea and the previous Viimsi Island joined with the mainland. During the Limnea Sea stage (4400 cal yr BP up to the present, the highest coastline at ca 12 m a.s.l.) land increased mostly at the back of Kakumäe and Kopli bays. The Kakumäe Peninsula obtained its outline about 2800 years ago, the Kopli Peninsula ca 1000 years later. The Paljassaar Peninsula was the latest to be formed ca 100 years ago. The attached palaeogeographical maps display shore displacement during the different stages of the Baltic Sea in the vicinity of Tallinn.

Journal ArticleDOI
TL;DR: In this article, a stationary model of the vertical distribution of the concentration of suspended sediment in the bottom layer of a natural water body with a flat bottom is proposed. But the model is not suitable for the case of lutoclines.
Abstract: The paper suggests a stationary model of the vertical distribution of the concentration of suspended sediment in the bottom layer of a natural water body with a flat bottom. The model explains the concentration distribution, formed jointly by the settling of suspended particles and turbulent diffusion. The flow is assumed geostrophic above the bottom-influenced layer, while in the bottom layer the effect of turbulent diffusion by the large-scale turbulence constituent is assumed to dominate over the diffusion effect caused by the small-scale turbulence constituent. It is shown that for the characteristic diffusion length scale of the eddies much smaller than the height of the Ekman bottom boundary layer the model results in an analytic expression for the vertical distribution of the concentration of suspended sediment, which includes also the case with the presence of the lutocline. The model outcome is compared with the results of a laboratory experiment with sand-injected flume flow.

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TL;DR: In this article, a very small basin, the former mire of Verevainu, in the nearest vicinity of ancient Keava settlements (8th−11th centuries) and hillforts (5th-13th centuries), was investigated by means of palaeo-ecological approach, namely by pollen, charcoal, and loss-on-ignition analyses and radiocarbon dating.
Abstract: Peat record from a very small basin, the former mire of Verevainu, in the nearest vicinity of ancient Keava settlements (8th−11th centuries) and hillforts (5th-13th centuries), was investigated by means of palaeoecological approach, namely by pollen, charcoal, and loss-on-ignition analyses and radiocarbon dating. The study aimed at ascertaining the appearance of prehistoric man in the area and reconstructing the local vegetation history and human impact on the environment around the inhabitation centre. The first sporadic cereal pollen grains appeared in the sediments in the Late Bronze Age at ca 1500 BC. Both peat ignition residue values as indicators of topsoil erosion and pollen evidence suggest forest clearance, opening of landscape, and cultivation of cereals from the Pre-Roman Iron Age. Approximately at AD 350-500 the rate of human impact upon environment increased notably.

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TL;DR: In this article, the authors studied the silurian dolostones representing the Jaani (Verknė and Jocionys formations (Fms)) and Minija (Pabradė Formation (Fm.) regional stages.
Abstract: Silurian dolostones representing the Jaani (Verknė and Jocionys formations (Fms)) and Minija (Pabradė Formation (Fm.)) regional stages were studied in the Jocionys 299 borehole located in eastern Lithuania. In addition to petrological studies, dolostones were subjected to XRD, XRF and ICP-MS analyses. X-ray diffraction analysis revealed that dolomite crystals in dolostones were very close to stoichiometric and well ordered and could be interpreted as early diagenetic. Strontium in dolostone of the Pabradė Fm. is comparable to that of other ancient dolomites, and is much lower than Sr concentrations in typical modern marine dolomites. Slight enrichment in Sr and S in the Verknė and Jocionys Fms is due to the presence of celestine (SrSO4) and gypsum. Evaporative (sabkha), seepage-reflux, mixing-zone, burial and seawater dolomitization models of modern and ancient examples from literature were considered. For the Jocionys Fm. we suggest seepage-reflux and burial (?) models. Evaporative (sabkha) and mixing-zone dolomitization models may be applied to the Verknė Fm. and the Pabradė Fm., respectively.

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TL;DR: The Dubiciai basin was studied by means of geomorphological, lithological and cartographic methods in order to reconstruct water level changes during postglacial time as discussed by the authors, and the last major change in the hydrographic network occurred in 1958-59 when an artificial drainage project was completed.
Abstract: The Dubiciai glaciolacustrine basin was studied by means of geomorphological, lithological and cartographic methods in order to reconstruct water level changes during postglacial time. The formation of the basin and respective sedimentation processes began immediately after the deglaciation. Glaciolacustrine terraces in the Dubiciai basin formed during the Frankfurt (Grūda) Stage of the last glaciation, and during the Dryas-Allerod, Boreal and Subatlantic chronozones. Intense evolution of the basin took place at the end of the Late Pleistocene and in the Early Holocene. The greatest changes in the topography were due to thermokarst processes which began in the Allerod and continued until the Boreal. Climate became warm and moist at the beginning of the Preboreal and thus created good conditions for accumulation of gyttja, peat and freshwater lime. The latest stage in the development of the Dubiciai basin occurred in the 19th century. In 50 years the area of the basin decreased by 10 times: from 221 ha in 1850 to 20 ha in 1900. The last major change in the hydrographic network of the basin occurred in 1958-59 when an artificial drainage project was completed.

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TL;DR: A new glyptorthid brachiopod species Bassettella alata with surface pits and lamellose frills is described from the Upper Ordovician Haljala and Keila stages of northern Estonia as mentioned in this paper.
Abstract: A new glyptorthid brachiopod species Bassettella alata with surface pits and lamellose frills is described from the Upper Ordovician Haljala and Keila stages of northern Estonia. The new species appears in the Johvi Substage of the Haljala Stage (mid-Sandbian) and is somewhat younger than the type species B. gracilis appearing in the lower Idavere Substage of the same stage in NW Russia. In the uppermost Keila Stage (lowermost Katian), B. alata belongs to a mixed faunal association of the marginal facies of the Vasalemma Formation comprising the oldest Ordovician reefs in Estonia. The distribution pattern of brachiopods of the genus Bassettella shows a westward shift in time and changes in shell morphology from subrectangular to subtriangular with alate cardinal extremities.

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TL;DR: In this paper, Brauer and Dulski used micro X-ray fluorescence (XRF) method to analyze clasticbiogenic varves from Lake Nautajärvi (Southern Finland).
Abstract: Keynote ..........................................................................................11 Brauer and Dulski , Combing varve micro-facies analyses and μ-XRF element scanning Snowball et al. , Refining a varve chronology using independent dating techniques: a Swedish case study Tylmann , How to find varves? Examples from Poland Oral and poster presentations ...............................................................25 Aritztegui and Anselmetti , Annually resolved environmental history of Lake Butrint (Albania) for the last 300 years Behl et al. , Extending an intermittently varved record of abrupt and millennial-scale Climate and ocean change through the Pleistocene in Santa Barbara Basin, California USA Besonen et al. , AMS C dates and the reworking of terrestrial macrofossils as deduced from a varve chronology Corella et al. , Climate fluctuations in Western Mediterranean during the last 1.5 ka: the varved record of Lake Montcortès (NE Spain) Darin and Kalugin , Geochemical indicators of climate change in lacustrine varves Central Asia Delaney , The Potential for Constructing Varve Chronologies and Reconstructing Ice Dynamics using MIS Stage 2 Ice-Contact Lake Deposits in Ireland and Great Britain Enters and Zolitschka , Proposal for an online varve image library – removing misconceptions about varves Fortin et al. , Investigating the presence of varved lake sediments in the Boreal Québec Labrador region Francus and Nobert , An integrated computer system to acquire, process, measure and store images of laminated sediments Hajdas and Michczy ński , Varve chronology of lake Soppensee (CH) compared with the age-depth model based on the high resolution C chronology Heinsalu , Different aquatic ecosystem response to the 8.2 ka cooling event: two diatom based high resolution case studies of varved sediments in southern Estonia and central southern Finland Kemp et al. , Palaeoclimatic and palaeoceanographic variability from Late Cretaceous Marine varve records Kosonen et al. , Using micro X-ray fluorescence (XRF) method to analyze clasticbiogenic varves from Lake Nautajärvi (Southern Finland) Lamoureux , The environmental signal contained in nonglacial Arctic varves: lessons from seven years of intensive lake and watershed process research MacLeod et al. , Developing an annually-resolved record for the Lateglacial period in the UK: challenges and progress Marshall et al. , Suigetsu Varves 2006: utilising μXRF and X-radiography for varve counting Martín-Puertas et al. , Mid-Holocene climate variability from Meerfelder Maar (Western Europe)