- Glaciology, Quaternary Geology, Glacial Geology, Glacial Geomorphology, Subglacial Environments, Drumlins, and 11 moreIce stream, Glacial geology and climate change, Glacier dynamics, Lithostratigraphy, Subglacial Hydrology, Geomorphology, Sedimentology, Geographic Information Systems (GIS), Remote Sensing, Geography, and Latviaedit
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Holocene relative shore‐level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho‐, biostratigraphical and chronological data with remote sensing and... more
Holocene relative shore‐level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho‐, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the Ģipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before c. 9.1 cal. ka BP) to coastal fen (c. 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (c. 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (c. 4.8 to 4.6 cal. ka BP), fen (c. 4.6 to 4.2 cal. ka BP), and river floodplain (since c. 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the Ģipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the last marine transgression in the western Gulf of Riga started at c. 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the Ģipka lagoon between c. 7.7 and 4.8 cal. ka BP, with the highest salinity c. 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period c. 6.0 to 5.0 cal. ka BP.
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Volume Scientific Technical Report STR19/01 Field Symposium of the INQUA PeriBaltic Working Group “FROM WEICHSELIAN ICE-SHEET DYNAMICS TO HOLOCENE LAND USE DEVELOPMENT IN WESTERN POMERANIA AND MECKLENBURG”
Research Interests: Geology and Paleontology
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Research Interests: Geology, Weathering, SEM, Aeolian, Quartz, and 7 moreGreenland, Periglacial, Cryoconites, Glaciers, Glacial, Glacier, and Baltica
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Active evaporite karst processes in the Baltic states are associated with a few relatively small regions where gypsum rocks can be found close to the Earth's surface. One of these areas lies in the vicinity of the Pandu bog. However,... more
Active evaporite karst processes in the Baltic states are associated with a few relatively small regions where gypsum rocks can be found close to the Earth's surface. One of these areas lies in the vicinity of the Pandu bog. However, such a possibly active karst region, which is covered by peat and in which the mapping of karst formations is complex, has not been previously investigated. In this study, we present a buried and peat‐filled karst cover‐collapse sinkhole mapping approach that involves a combination of ground‐penetrating radar (GPR), electrical resistivity tomography (ERT) and conventional boreholes. A detailed map of the bog's substratum topography was constructed from a geophysical surveying dataset. It reveals 15 distinctly expressed sinkholes with diameters of several tens of metres. Overall, 140 potential sinkholes were also mapped using remote sensing data in the vicinity of the bog. Higher electrical resistivity anomalies were identified inside the peat; they coincide with scatter‐free zones in GPR data and water layers in boreholes. Highly disturbed internal peat layering was also detected in these sinkholes. It is suggested that these water layers and disturbed peat layering may have formed due to the subsidence of the lower peat layers, and thus they represent relatively younger sinkholes. This is also supported by evidence from orthophoto maps, which showed the formation and disappearance of surficial lakes and depressions on the bog surface. Our results revealed the presence of active and widespread karst processes under the bog that have not been previously noticed despite the fact that they have implications for the assessment of geohazards in this area.
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Abstract This study presents the detailed surveys of the NE outlet of Eyjabakkajokull glacier, East Iceland, from the combination of low-frequency ground penetrating radar (GPR), unmanned aerial vehicle (UAV) and GNSS measurements. Data... more
Abstract This study presents the detailed surveys of the NE outlet of Eyjabakkajokull glacier, East Iceland, from the combination of low-frequency ground penetrating radar (GPR), unmanned aerial vehicle (UAV) and GNSS measurements. Data analyses reveal the complex subglacial topography with a prominent, up to 45-m-deep longitudinal trough in the central part of the outlet that serves as the main trunk for the fast ice flow during the glacier surges. During the last decade (2010–2018), the studied part of the glacier has thinned by 4.37 m/yr on average and the ice margin has retreated ~750 m. We detect a boundary between scatter-free zone and zone of intense scattering near the ice margin and relate it to the level of piezometric surface. A very well-developed englacial drainage network in the marginal area of Eyjabakkajokull is determined from the mapped moulins and englacial hyperbolae mainly representing englacial channels. The compressional regime near the almost stagnant ice margin is confirmed from the analysis of the surface structures.
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Lamsters, K. Madlienas nolaidenuma glaciālās reljefa formas un to veidošanās apstākļi. Maģistra darbs. Rīga, Latvijas Universitāte, Ģeogrāfijas un Zemes zinātņu fakultāte, 2011. Maģistra darbā ir veikts pētījums par Madlienas nolaidenuma... more
Lamsters, K. Madlienas nolaidenuma glaciālās reljefa formas un to veidošanās apstākļi. Maģistra darbs. Rīga, Latvijas Universitāte, Ģeogrāfijas un Zemes zinātņu fakultāte, 2011. Maģistra darbā ir veikts pētījums par Madlienas nolaidenuma glaciālajām reljefa formām un to veidošanās apstākļiem. Lielākā uzmanība ir pievērsta drumlinu morfoloģijai, telpiskajam sakārtojumam un iekšējai uzbūvei, kas detāli pētīta Brencēnu kalna drumlinā. Darba rezultātā ir izveidota ģeomorfoloģiskā kartoshēma, kurā attēloti drumlini, gala morēnas, bīdes sānu morēnas, marginālās grēdas un osi. Ir noteikti drumlinu morfoloģisko parametri, veikta to ģeotelpiskā un statiskā analīze. Lauka pētījumos apsekoti atsegumi karjeros, veikta slāņu saguluma elementu uzmērīšana, ģeoloģiskā urbšana ar rokas urbi, radilokācijas profilēšana, ledāja skrambu uzmērīšana un paraugu noņemšana OSL datējumiem. Raksturvārdi: Madlienas nolaidenums, drumlini, gala morēnas, deformācija, ledāja plūsma.Lamsters, K. Glacial landforms an...
Research Interests: Geology and Archipelago
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Pētījums ir veikts par Fenoskandijas ledus vairoga Zemgales loba subglaciālajām reljefa formām un ledāja dinamiku Viduslatvijas zemienē un Ziemeļlietuvas līdzenumos, akcentējot drumlinu, lielizmēra glaciālo lineamentu, rievoto morēnu un... more
Pētījums ir veikts par Fenoskandijas ledus vairoga Zemgales loba subglaciālajām reljefa formām un ledāja dinamiku Viduslatvijas zemienē un Ziemeļlietuvas līdzenumos, akcentējot drumlinu, lielizmēra glaciālo lineamentu, rievoto morēnu un ledājūdeņu straumju lineāro veidojumu morfoloģiju, telpisko sakārtojumu, iekšējo uzbūvi un veidošanās apstākļu kopsakarību ar ledāja–gultnes mijiedarbības zonas termālo apstākļu laiktelpiskajām izmaiņām. Balstoties uz lielmēroga topogrāfisko karšu un augstas izšķirtspējas reljefa modeļu analīzi, kartētas subglaciālās reljefa formas un iegūti to morfometriskie parametri. Lauka pētījumos ir iegūti oriģināli, ģeotelpiski precīzi piesaistīti dati par subglaciālo reljefa formu iekšējo uzbūvi, to veidojošo nogulumu uzkrāšanās apstākļiem un glaciotektoniskās deformācijas struktūrām. Izmantojot OSL datēšanas metodi, noskaidrots smilšaino nogulumu vecums, kas atbilst Vislas leduslaikmeta sākumposmam un vidusposmam. Izvērtētas subglaciālo reljefa formu izkārto...
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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... more
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 ...
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Unmanned Aerial Vehicles (UAVs) are being increasingly used in glaciology demonstrating their potential for the generation of high-resolution digital elevation models (DEMs) that can be further used for the evaluation of glacial processes... more
Unmanned Aerial Vehicles (UAVs) are being increasingly used in glaciology demonstrating their potential for the generation of high-resolution digital elevation models (DEMs) that can be further used for the evaluation of glacial processes in detail. Such investigations are especially important for the evaluation of surface changes of small valley glaciers, which are not well-represented in lower-resolution satellite-derived products. In this study, we performed two UAV surveys at the end of the ablation season in 2019 and 2021 on Waldemarbreen, a High-Arctic glacier in NW Svalbard. We derived the mean annual glacier surface velocity of 5.3 m. The estimated mean glacier surface elevation change from 2019 to 2021 was −1.46 m a−1 which corresponds to the geodetic mass balance (MB) of −1.33 m w.e. a−1. The glaciological MB for the same period was −1.61 m w.e. a−1. Our survey includes all Waldemarbreen and demonstrates the efficiency of high-resolution DEMs produced from UAV photogrammet...
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The western ablation zone of the Greenland ice sheet is darker than the surrounding ice, because a higher amount of fine-grained particles, known as a cryoconite, occur. To date, biotic cryoconite components have gained a lot of... more
The western ablation zone of the Greenland ice sheet is darker than the surrounding ice, because a higher amount of fine-grained particles, known as a cryoconite, occur. To date, biotic cryoconite components have gained a lot of attention, in contrast with mineral components, which have been studied to a limited extent. In this study, fine-grained quartz grains from the cryoconite holes of the Russell Glacier, southwest Greenland are, therefore, examined. Authors use scanning electron microscope to elucidate shape, surface character and origin of these mineral quartz particles. Triangular-faceted, sharp-edged grains dominate in most of the investigated samples, and originate from local sources, where grain-to-grain contact in the ice prevail. Grains with smooth corners and edges result from chemical weathering in meltwater of alkaline pH, in which quartz solubility significantly increases. However, part of these rounded grains is due to mechanical abrasion by wind action. Postsedime...
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These data contain photogrammetrical data collected by unmanned aerial vehicle (UAV) from February to March 2018 in the Argentine Islands, Wilhelm Archipelago, West Antarctica. The data include processed data (orthoimages and digital... more
These data contain photogrammetrical data collected by unmanned aerial vehicle (UAV) from February to March 2018 in the Argentine Islands, Wilhelm Archipelago, West Antarctica. The data include processed data (orthoimages and digital surface models) with the Structure-fom-Motion photogrammetrical software Agisoft Metashape. Data are cropped by the outlines of islands. Data are organized by the name of the surveyed island. The coordinate system used is UTM Zone 20S based on WGS84. The data are related to the article "High-resolution orthophoto map and digital surface models of the largest Argentine Islands (the Antarctic) from unmanned aerial vehicle photogrammetry", Lamsters, K., Karušs, J., Krievāns, M., Ješkins, J., Journal of Maps.
Although measurements of thickness and internal structure of glaciers are substantial for the understanding of their evolution and response to climate change, detailed data about polythermal glaciers, are scarce. Here, we present the... more
Although measurements of thickness and internal structure of glaciers are substantial for the understanding of their evolution and response to climate change, detailed data about polythermal glaciers, are scarce. Here, we present the first ground-penetrating radar (GPR) measurement data of Irenebreen, and high-resolution DEM and orthomosaic, obtained from unmanned aerial vehicle (UAV) photogrammetry. A combination of GPR and UAV data allowed for the reconstruction of the glacier geometry including thermal structure. We compare different methods of GPR signal propagation speed determination and argue that a common midpoint method (CMP) should be used if possible. Our observations reveal that Irenebreen is a polythermal glacier with a basal temperate ice layer, the volume of which volume reaches only 12% of the total glacier volume. We also observe the intense GPR signal scattering in two small zones in the ablation area and suggest that intense water percolation occurs in these place...