Baltica最新文献

{"title":"Evidence of ice streaming and ice tongue shutdown in western Latvia: revealed from the mapping of crevasse-squeeze ridges","authors":"K. Lamsters, Zane Vītola, J. Karušs, P. Džeriņš","doi":"10.5200/baltica.2021.1.1","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.1","url":null,"abstract":"Glacial geomorphological mapping of western Latvia using a 1-m-resolution digital elevation model generated from airborne LiDAR data has revealed two sets of mega-scale glacial lineations (MSGLs), one of which is superimposed by crevasse-squeeze ridges (CSRs). CSRs occur as a dense ridge network with a dominant orientation of ridges perpendicular to the ice flow direction. The landform assemblage is interpreted as evidence for two separate phases of fast ice flow with different ice flow directions during the overall deglaciation of the Fennoscandian Ice Sheet (FIS). The first fast ice flow phase occurred from the northwest by the Usma Ice Lobe that extended in the Eastern Kursa Upland. The second fast ice flow occurred from the north by the Venta Ice Tongue in a narrow flow corridor limited mainly to the Kursa Lowland. Active ice streaming caused ice crevassing perpendicular to the ice flow direction and formation of CSRs by squeezing of subglacial till into basal crevasses. A good preservation of the CSRs and general lack of recessional moraines suggest widespread stagnation and ice mass melting after the shutdown of the Venta Ice Tongue followed by the formation of the Venta-Usma ice-dammed lake and glaciolacustrine deposition in the lowest areas of lowland. Our data provide the first evidence of CSRs in the south-eastern terrestrial sector of the FIS suggesting the dynamic ice streaming or surging behaviour of the ice lobes and tongues in this region during deglaciation.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contribution of winter upwelling in the Gulf of Finland to lake-effect snow in Estonia","authors":"Ü. Suursaar, Helve Meitern","doi":"10.5200/baltica.2021.2.1","DOIUrl":"https://doi.org/10.5200/baltica.2021.2.1","url":null,"abstract":"The aim of the study was to analyse the sequence of winter (“warm”) upwelling and lake-effect snow (LES) events that deposited up to 50 cm of snow along the North Estonian coast in January–February 2021. Based on weather and aerological data, four episodes of LES were documented. Heavy, localized lake-effect enhanced precipitation occurred along a 30–50 km wide coastal strip bordering the Gulf of Finland when a cold air mass from the north advected over the warmer, unfrozen sea surface. A temperature difference of up to 20°C was revealed between the air mass temperatures measured at the 850 hPa level and at the sea surface. The LES events, in turn, were preceded by upwelling in the southern Gulf of Finland, which was generated by persisting easterly winds. Even when occasionally interrupted by a wind change, the upwelled water still kept sea surface temperature (SST) in the southern half of the Gulf higher, as documented by the water temperature records from the coastal stations of Estonia, SST and salinity imagery retrieved from the SatBaltyk system, and sea ice distribution charts. Differently from summer (cold) upwelling, winter upwelling brought up warmer (2–4°C) water from the sub-surface layers replacing the already cooled down (0–1°C) surface water. Thus, winter upwelling enhanced LES in two ways. Firstly, by not letting the Gulf freeze over, and therefore by providing a fetch. And secondly, by increasing the SST (and therefore also the 850 hPa level – surface temperature difference) by up to 4°C.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polycyclic aromatic hydrocarbons in various Lithuanian water bodies and a positive matrix factorization-based identification of pollution sources","authors":"E. Raudonytė-Svirbutavičienė, R. Stakėnienė, I. Baužienė, K. Jokšas","doi":"10.5200/baltica.2021.1.2","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.2","url":null,"abstract":"In this study, results on PAHs distribution, origin and ecological risks from several surveys are combined with a special focus on naphthalene. The study area comprises a large part of the Lithuanian territory and includes two biggest Lithuanian rivers, Nemunas and Neris (sampling locations with different hydrodynamics and varying anthropogenic pressure), four different lakes and the central part of the Curonian Lagoon. ∑16PAHs concentrations in the surface sediment ranged between 74.5 and 6377 ng g-1 dw. In 9 locations out of 14, naphthalene concentration exceeded TEL and posed a threat to the environment. Naphthalene was a significant contributor to the total PAHs concentration in the study area with concentrations ranging from 0.78 to 106 ng g-1 dw. Despite the highest naphthalene concentration recorded in Lake Talkša, naphthalene had only a minor contribution to the PAH profile in this lake. Even a lower impact of naphthalene was observed in the Curonian Lagoon. Naphthalene was found to be the prevailing compound in the Nemunas River Delta region, in a relatively clean Lithuanian Lake Dusia and in some Neris River locations. The highest contribution of naphthalene was observed in the areas with low urbanization degree, but close to peatlands. The main naphthalene source in the study area might be related to peatlands, albeit additional naphthalene sources, such as food cooking, burning of agricultural residues, wood and coal could not be completely rejected either. The sources of other PAHs are attributed to the vehicular emission, emissions from industry, biomass and coal burning.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Undrained shear strength of glacial till soils and its determining factors","authors":"Domas Gribulis, K. Dundulis, Saulius Gadeikis, Sonata Gadeikienė","doi":"10.5200/baltica.2021.2.8","DOIUrl":"https://doi.org/10.5200/baltica.2021.2.8","url":null,"abstract":"This article presents results of the test conducted on the undrained shear strength of till clayey soils of Eastern Lithuania, which are characterized by rigid and very stiff consistency and low plasticity. According to the classification of soils presented in LST EN ISO 14688–2:2018 Geotechnical Investigation and Testing – Identification and Classification of Soil − Part 2: Principles for a Classification, the tested soils are classified as sandy low plasticity clays. The undrained shear strength was tested using the triaxial compression (unconsolidated undrained) method. The test results showed that peculiarities of the particle size distribution had a crucial impact on the undrained strength of these soils, i.e. on the correlation of clay and fine silt fractions with the rest of soil components.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive spatiotemporal evaluation of the current earthquake activity in different parts of the Frakull-Durrës fault zone, Albania","authors":"S. Öztürk, R. Ormeni","doi":"10.5200/baltica.2021.1.5","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.5","url":null,"abstract":"This study presents a detailed spatiotemporal analysis for the Frakull-Durrës (F-D) fault zone at the beginning of 2020. For this purpose, the most frequently used statistical seismicity parameters such as magnitude completeness, Mc-value, Gutenberg-Richter b-value, recurrence times, annual probabilities and standard normal deviate, Z-value, were mapped. The F-D fault zone was divided into two seismogenic subregions, and Mc-value was taken as 2.5 for both the south and north parts. The b-value was estimated as 0.83 ± 0.06 for the south part and 0.85 ± 0.06 for the north part. b-values for both zones are smaller than 1.0 and these values may be considered to be a larger stress accumulation to build up over time and to be released by the next possible earthquakes. Clear decreasing trends were observed in time variations of b-values before the occurrences of several strong main shocks. Analyses of annual probabilities and recurrence times suggest that the study region has an intermediate/long-term earthquake hazard in comparison to occurrences of strong/destructive earthquakes in the short term. Some anomaly regions of a small b-value and a large Z-value were found along the F-D fault zone at the beginning of 2020: i) among Lushnje-Tirana-Durrës including the middle part of the F-D fault zone, ii) in and around Lezha including the north end of the F-D fault zone. Thus, the combination of regions with the lowest b-value and largest Z-value may supply preliminary results for earthquake hazard, and these regions may be considered to be the most likely regions for future strong/large earthquakes in the F-D fault zone.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation and mapping of the temporary dynamics of the highest Lithuanian outcrop using ground-based measurements and UAV imagery","authors":"Arturas Bautrenas, A. Česnulevičius, Regina Regina, Linas Bevainis, Aušra Kumetaitienė, Donatas Ovodas, Neringa Maciuleviciute-Turliene, Loreta Šutinienė, Viktoras Karaliunas, Aldona Baubinienė, I. Baužienė","doi":"10.5200/baltica.2021.1.9","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.9","url":null,"abstract":"The main goal of the study is to evaluate changes that have occurred in the Pūčkoriai outcrop surface over the 2014–2019 period and to compare the accuracy of ground-based measurements with that of UAV aerial image models. Ground-based measurements were performed applying the original methodology, which involves comparison of the first one and subsequent beam direction. For surface change surveys, we used repeated terrestrial geodetic measurements and UAV imagery. Ground-based measurements were performed using a Trimble M3 Total Station (with RTK); aerial images were captured using UAV INSPIRE1 with a ZENMUSE X3 camera. Pix4D photogrammetric software was used to create a DEM. The comparison of repeated terrestrial measurements and UAV aerial imagery revealed that the average change in the outcrop surface altitude over the period 2014–2019 amounted to 8.3 cm, with a maximum of 24.23 cm and a minimum of 0.33 cm. Contactless remote sensing allows obtaining data without affecting or altering the surface of the exposed deposits. The difference between terrestrial geodetic measurements and the UAV-based DEM did not exceed the following values: ΔX and ΔY ≤ 68 mm; ΔZ ≤ 21 mm. Previous research has shown that the use of UAV aerial photography images for assessing changes in outcrops consisting of loose sediment layers yields sufficiently accurate results. The present study focuses on the determination of quantitative indicators of seasonal changes in the outcrop surface. Quantitative surface changes of the outcrop were mapped based on dynamic signs, surface comparison and a formal choropleth map (10 × 10 m); dynamic zones of the outcrop were distinguished based on the results obtained employing these methods. The data obtained can be extrapolated to other Lithuanian river outcrops, which are characterized by a variety of sediments.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of microplastic occurrence on the sandy beaches of Šventoji, Lithuania","authors":"E. Raudonytė-Svirbutavičienė, R. Stakėnienė, K. Jokšas, I. Matulaitienė, L. Mikoliūnaitė, A. Zarkov, A. Kareiva","doi":"10.5200/baltica.2021.1.4","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.4","url":null,"abstract":"In this study, a sandy beach in Šventoji, Lithuania, a popular albeit not highly urbanised touristic destination, was analysed for microplastic pollution in the summer of 2019. The presence and abundance of microplastics in different sites of the beach were evaluated. Šventoji Beach was found to be significantly polluted with microplastic, its concentration ranging from 85 to 325 MPs kg−1dw. Such concentrations are relatively high if compared to other Baltic Sea coasts and worldwide. The physico-chemical characteristics of the plastics showed limited variability. Blue fibres were prevailing over other types of microplastics. Blue and red/orange fibres were identified as nylon containing copper–phthalocyanine dyes, while red/orange fibres as high-density polyethylene. This study provides new insights into the application and development of microplastic analysis methods for the coastal sands of the Baltic Sea.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"42 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topography of the Aleutian Trench south-east off Bowers Ridge, Bering Sea, in the context of the geological development of North Pacific Ocean","authors":"Polina Lemenkova","doi":"10.5200/baltica.2021.1.3","DOIUrl":"https://doi.org/10.5200/baltica.2021.1.3","url":null,"abstract":"The research is focused on the topographic modelling and mapping of the Aleutian Trench. The study area is situated in the Bering Sea, a marginal sea located northernmost of the Pacific Ocean, between Alaska and Kamchatka Peninsula. The geological setting of the region is characterized by the subduction of the oceanic Pacific Plate below the continental North American Plate. Other features include high seismic activity along the Aleutian island arcs bordering the oceanic seafloor. The objective of this paper is to explore the interaction between the geophysical setting affecting the relief of the seafloor by using geoinformation techniques and geological analysis. In the hypothesis of this study, variations in the geophysical fields as independent variables are reflected in the morphology of the seafloor, which can be observed using data visualization by the advanced cartographic scripting solutions. The open source high-resolution topographic map (ETOPO1), marine free-air gravity and Bouguer gravity anomaly data were used and integrated to investigate the potential correlation between the geophysical, geological, tectonic and topographic settings of the Bering Sea. Our main method includes bathymetric mapping of the area with publicly available bathymetric data using GMT. Materials include open source data: ETOPO1 raster grid with 1 arc-minute resolution, EGM96 gravity and vector contour layers of GMT. The research included complex thematic mapping of the region, including topographic, contour, geodetic and geophysical mapping, 3D modelling and geomorphological plotting of the 30 cross-section segments of the trench located SE off the Bowers Ridge. According to the processed ETOPO1 dataset, the minimal depth is -8480 m and the mean is -3089.154 m. The geoid undulations model shows that the majority of the gravity values lie in the interval between -10 and 20 m with the lowest values along the trench. The statistical histogram shows that the most common depth value in the segment of the Aleutian Trench is -4800 m, occurring 1722 times. The profile linear trend modelling was done with four different approaches of the regression model (y = f(x) + e) by weighted least squares (WLS) with arguments: 1) m2t = a + bt (polynomial model degree one); 2) m3t = a + bt + ct2 (polynomial model degree two); 3) m4t = a + bt + ct2 + dcos2π*t + esin2π*t (polynomial model with Fourier series one); and 4) additional plotting residuals. Surface modelling was performed using xyz modelling from the ASCII data enlarging fragment towards SE of the Bowers Ridge. The tested functionality of modules of GMT presented an effective cartographic scripting toolset enabling a precise topographic mapping and 3D modelling. The paper contributes to a more detailed understanding of the Pacific Ocean seafloor bathymetry, more specifically of the selected segment of the Aleutian Trench near Bowers Ridge area.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of the Fractal Dimension of the Active Fault Data along the East Anatolian Fault Zone","authors":"Ebru Aydindag Bayrak, Pınar Kırcı","doi":"10.5200/BALTICA.2021.1.6","DOIUrl":"https://doi.org/10.5200/BALTICA.2021.1.6","url":null,"abstract":"The current study has analyzed active fault data along the East Anatolian Fault Zone (EAFZ) applying both manual (classic) and modern versions of the box counting method. The EAFZ active fault dataset used for analysis was taken from the Geoscience Map Viewer and the Drawing Editor from the website of the General Directorate of Mineral Research and Exploration. The study covered an area stretching from Karlıova in the north to Kırıkhan in the south. The fractal analysis of the earthquake surface rupture and the Holocene fault data was performed. Fractal dimensions of the EAFZ active-fault data were calculated for 15 boxes and compared with correlation coefficient values. The calculated fractal dimension values were found to vary with the density of the active-fault data falling into the boxes. The maximum fractal dimension value D1 was determined for Karlıova and its surroundings, which can be associated with the fault density due to the branching geometry.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insight into the palaeoenvironmental dynamics as a background of the human history in the Nemunas River delta region, W Lithuania, throughout the Lateglacial and Early Holocene","authors":"A. Damušytė, M. Stančikaitė, Žana Skuratovič, Domas Uogintas, Darius Valūnas, A. Girininkas, Tomas Rimkus, L. Daugnora, Vladas Žulkus, G. Vaikutienė","doi":"10.5200/baltica.2021.2.7","DOIUrl":"https://doi.org/10.5200/baltica.2021.2.7","url":null,"abstract":"A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a background of the habitation history in the territory of the Nemunas River Delta (NRD) was based on the geological-geomorphological, grain-size, isotope (14C), pollen and diatom data supplemented by archaeological information obtained within the framework of the project „Man and Baltic Sea in the Meso-Neolithic: Relict Coasts and Settlements Below and Above Present Sea Level. ReCoasts&People“. The existence of extended proglacial lakes formed during the onset of the Lateglacial was succeeded by a period of low water estuaries or freshwater lagoons as early as 13.8 cal kyr BP. Simultaneously, groups of the Final Palaeolithic population, representing the classic Swiderian culture, inhabited the area. As shores of the Yoldia Sea and Ancylus Lake were situated further westwards (-11 to -24 – -29 m NN), wetlands and lake systems alongside with shallow boggy basins and fluvial streams predominated in the local landscape throughout the Early Holocene. Archaeological data suggest an episodic human activity in the territory while part of the archaeological sites might have been covered by sediments during the further intervals of the Holocene. Since the Early Holocene an extended peat bogs have become an important part of the landscape here.","PeriodicalId":55401,"journal":{"name":"Baltica","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70648925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}