Combined sedimentological and palaeontological studies of the vertebrate fossil-bearing deposits of the Upper Devonian, Upper Famennian Ketleri Formation have provided new data on the sedimentary environment of the deposits, as well as on taxonomic and taphonomic peculiarities of the fossil assemblage. Data from numerical modelling of the Baltic Devonian Basin demonstrate that the sandy deposits of the Pavāri and Varkaļi members form a fan-shaped area resembling a wide delta developed in shallow-marine settings. Fluvial channels and bars with strong tidal influence were identified in a sedimentological study of the Pavāri site, suggesting a tide-influenced fluvial environment. Taphonomic studies indicate that the sedimentary concentrations of well-preserved vertebrate remains were formed under the influence of fluvial and strong tidal processes in a shallow-water environment, most likely in tide-influenced deltaic settings. Trace fossils recognised in the Ketleri and Pavāri-1 sites suggest a brackish-water or marine environment, and thus support the hypothesis. The analysis of rhizocretes from the Varkaļi Member suggests the strong influence of a seasonal climate. Well-preserved plant macroremains have been discovered for the first time during this study in the Ketleri Formation.

Plant-based data from southern Finland were used to reconstruct late Holocene warm-season temperature variability on inter-annual to longer scales. Temperature-sensitive records representing maximum latewood density of Pinus sylvestris tree rings (since AD 760) and phenological stages of several plant species (since AD 1750) explained ~60% and ~70% of instrumentally observed temperature variance, respectively. The value of a multi-proxy approach was demonstrated by statistical models including both variables, which explained ~80% of the temperature variance. Temperatures from the CRUTEM5 and Berkeley datasets had slight variations in their correlativity with proxy data, possibly resulting from their differing spatial representativeness over the proxy sites. Temperature history inferred from maximum latewood densities extended over the past millennium and correlated with previously published data from similar proxy records in Fennoscandia and adjacent areas. These data indicate that the region cooled since the Medieval Climate Anomaly and warmed markedly since the Little Ice Age/Maunder Minimum. In the study region, the magnitude of this long-term warming was 2.1 °C and 2.8 °C, calculated between the coldest and warmest 100-year and 30-year intervals, respectively. Collectively, our results display the potential of plant-based data from low-lying and mild boreal sites to extend our understanding of preindustrial and recent climatic changes.

Supplementary files 1 and 2 are designed to provide an in-depth analysis, including the complete analyzed geochemical dataset of the Alutaguse zone.

Latvia’s peatlands play an important role in achieving the country’s climate goals and preserving natural diversity. Approximately 10% of Latvia’s territory is covered by peatlands, more precisely defined as peat deposits. However, outdated inventories of these peatlands hinder the development of sustainable policies for managing natural recourses. This lack of data also complicates efforts to predict the extent of fens and assess their potential contribution to climate change mitigation, such as through rewetting activities. In this study, we assessed the extent of fens in one of Latvia’s largest municipalities – Ogre. After a feasibility study using GIS tools, fen peat deposits were randomly selected and surveyed in the field to determine the type, thickness, and characteristics of the peat. Among the 20 sites surveyed, only five corresponded to fen peat deposits (with a peat layer of at least 30 cm), and only one of these qualified as a fen also in terms of vegetation and moisture regime. Existing fen peat deposits are subject to intensive erosion, mineralization, and decomposition, leading to greenhouse gas emissions. The results indicate that there are significantly fewer fen peat deposits than previously assumed, and a detailed analysis of their extent, involving field inspection and verification at the national level, is needed.

This research focuses on the geochemical analysis of Paleoproterozoic metasedimentary and metavolcanic units in the Alutaguse region of northern Estonia, shedding light on the geodynamic evolution during the Svecofennian orogeny in eastern Fennoscandia. The metasedimentary units consist of micaceous gneisses (± Grt ± Crd ± Sil), and the metavolcanic units include amphibolites and pyroxenic gneisses. Geochemical analyses utilized both historical and new whole-rock geochemical data. Weathering indices indicated their applicability for provenance studies and tectonic setting analyses. Metasediments are classified by their silica content: high-SiO2 (>63 wt%) metasediments resemble litharenites, implying higher maturity and felsic origins akin to the upper continental crust reference; low-SiO2 (

The Orijärvi area within the Paleoproterozoic Uusimaa belt contains volcanic and minor sedimentary formations, providing valuable insights into the oldest Svecofennian crust in southern Finland. Previously, felsic volcanic rocks from the Orijärvi, Kisko and Toija formations have been dated at 1895 ± 3, 1878 ± 4 and 1878 ± 4 Ma, respectively. In the present study, the Sorvasto sample from the southern boundary of the Kisko formation yields a zircon age of 1885 ± 5 Ma and a titanite age of 1800 ± 15 Ma. The zircon age falls within the interval between previously obtained age determinations and is coeval with the common Svecofennian crustal growth stage. The Kavasto sample from the western part of the area yields a zircon age of 1878 ± 6 Ma and a titanite age of 1796 ± 4 Ma. The zircon age corresponds to those obtained for similar rock types in the Toija and Ahdisto formations. Picritic interlayers occur within all these successions and are here interpreted as belonging to the same Toija formation. We tentatively infer that the Toija and Salittu formations, together with the overlying sedimentary rocks, can be traced to the West Uusimaa area in the east and the Turku area in the west. The titanite ages near 1.80 Ga reflect cooling or reheating events.

The escalating impacts of global climate change significantly affect regional hydrological systems, particularly in northern areas such as Estonia. This study investigates the hydrological sensitivity of Estonian catchments to climatic variability, focusing on the interplay between surface water and groundwater. Using data from 42 river catchments, it employs various statistical methods in hydrology, emphasizing the autocorrelation function, cross-correlation function, baseflow index, and flow duration curve. The analysis spans the years 2012–2022, integrating hydrological, spatial, and water quality parameters. The research identifies four distinct hydrological behavior clusters: plateau, sandstone upland, carbonate upland, and lowland. Key findings include diverse catchment sensitivities to groundwater recharge, the role of baseflow in streamflow stabilization, the memory effect in catchment responses, and insights from the flow duration curve on flow variability and extremes. The LightGBM model, predicting focus parameters, highlights the critical influence of air temperature and snowpack on streamflow characteristics. This study underscores the diverse hydrological sensitivities of Estonian catchments to hydroclimatic changes, emphasizing the importance of considering catchment-specific characteristics in water resource management and policy-making. Contributing to the broader understanding of hydrological processes, it provides valuable insights for future research and environmental planning in the face of climate variability and change.