Geological Survey of Finland

Since 2004, marine biodiversity inventory data have been systematically collected with diving, video, and benthic sampling methods in Finland. To date, this collection of data consists of more than 194 000 spatially explicit observations, covering more than 280 aquatic genera, representing mainly macroalgae, vascular plants, water mosses, and invertebrates. We describe the data collection and storage methods, data extraction from national databases, and provide potential users a curated, open-access version of the inventory data. Additionally, examples of data applications and discussion on potential limitations are provided. This extensive dataset can be used in ecological and biogeographical studies to provide general descriptions of biodiversity patterns and species distributions, as well as in more applied studies to support marine management, conservation, and sustainable use of marine areas. The sampling strategy and high spatial and taxonomic resolution allow for statistical modelling, which further increases the usability of the data in research, for instance in identifying key biodiversity areas, estimating biodiversity loss, and assessing efficiency of conservation.

The paper presents fall cone experiments, their analysis with digital image processing and their replication with the Generalized Interpolation Material Point Method. The fall cone experiments were conducted on a soft and sensitive marine clay sample collected from the Gulf of Finland in the Baltic Sea. The paper presents experiments performed with a 30°, 100g cone, and a 60°, 60g cone dropped from different heights and recorded with a high-speed camera. The tests were supplemented with a laboratory test program to determine the geotechnical properties of the soil used in the tests. The Generalized Interpolation Material Point Method (GIMP) simulations shown in the paper replicate the process of indentation of the cone into the soil: the cone displacement, velocity, acceleration, and reaction force curves obtained with digital image processing. The simulations show that for an accurate replication of the process a strain-rate dependent Tresca constitutive model, extended with strain softening replicating destructuration is sufficient. The study examines the effect of cone geometry, cone mass, cone roughness, impact velocity, mesh density, strain rate and strain softening on the cone penetration process. The simulation results indicate that the presented framework can simulate the dynamic penetration process on soft and sensitive clay very well.

Acid sulfate soils are found globally and have significant environmental impact as a source for metals and acidity to surrounding streams that can cause, for example, large‐scale fish kills. In the face of changing climate and its effect on groundwater fluctuations, the environmental risk associated with these soils needs to be thoroughly investigated. This study examined the water‐soluble concentrations of multiple elements from the oxidized, transition and reduced zones of acid sulfate soil profiles situated on the Swedish coastal plains. By comparing untreated (naturally oxidized in field) and incubated samples from these zones, we gain insight into the current and near‐future mobilization and leaching of acidity and metals that occur in these soils. The results showed that concentrations of Al, Cd, Co, Mn, Ni, S and Zn mobilized from incubated samples were about an order of magnitude higher than from the untreated samples. Notably, the concentrations of mobilized Co, Mn and Ni were higher than released by 1 M HCl at the same sites, highlighting the particularly high mobility of these metals from in situ oxidation of acid sulfate soils. Conversely, Fe and Cu showed lower than expected water‐soluble concentrations and were also low compared to the 1 M HCl‐extractable element concentrations, likely due to rapid re‐mobilization of secondary Fe minerals. Arsenic, Cr and Pb showed overall low water‐soluble concentrations in both the incubated and untreated samples, consistent with these elements not being abundantly leached from acid sulfate soils. This observation was further supported by the retention of these metals in secondary Fe‐mineral phases such as jarosite and schwertmannite as reported in previous studies. A strong correlation between acidity and near‐total S indicated that S can serve as an indicator for the acidification risks associated with acid sulfate soil oxidation. Overall, the findings demonstrated that even a small lowering of the groundwater table can lead to significant mobilization of metals and acidity. This highlights the increased risks of environmental degradation in the face of climate change and intensified drainage operations and, thus, the need for proper management to reduce the risks.

Precambrian paleomagnetic studies are critical for testing paleogeographic reconstructions in deep time but rely on the fidelity of the assumption of the geocentric axial dipole (GAD) hypothesis. With high‐reliability data from mafic dykes and volcanic rocks, the scatter of individual virtual geomagnetic poles (VGPs) can be used to test simple GAD models. In order to conduct such a test, the VGPs must be adequate in number and in spatial coverage of the sampling sites. In this study, we targeted the 2.1 Ga Indin dyke swarm of the Slave craton. Building on previous sampling of the Indin dyke swarm in the western and central parts of southern Slave craton, we report results from 9 additional sites in the central and eastern parts of the craton, sites that significantly expand the width of the dyke swarm across the entire craton. The VGPs obtained from 7 of 9 newly identified Indin dykes are broadly similar to previously reported directions, expanding the total of VGPs for individual Indin dykes to n = 28, which is sufficient for a test of the GAD‐based statistical models using VGP scatter. The high VGP scatter of the Indin swarm can be attributed to the relatively high paleolatitude of 56° ± 6° for the Slave craton at the time of dyke emplacement. The Indin data have VGP scatter that is consistent with field models associated with the GAD hypothesis for the indicated paleolatitude, thus confirming the fidelity of the GAD field at ca. 2.1 Ga.

Remote sensing (RS) can be an efficient monitoring method to assess the ecological impacts of restoration. Yet, it has been used relatively little to monitor post‐restoration changes in boreal forestry‐drained peatlands, and particularly the linkages between changes in RS and plant species remain vague. To understand this gap, we utilize data from the Finnish peatland restoration monitoring network spanning 150 sites and a 10‐year post‐restoration monitoring period. We employ Bayesian joint species distribution models (Hierarchical Modeling of Species Communities) to study (1) the changes in optical Sentinel‐2 and Landsat satellite spectral signatures, (2) whether the RS variables improve predictions of vascular plant and moss species and functional type occurrence and cover, and (3) what kinds of associations exist between RS variables and plant species or functional types. Our results show that peatland restoration increases the reflectance of red and near‐infrared (NIR) bands in sparsely treed pine mire forests and open mires but not in densely treed spruce mire forests. Impacts on other tested RS variables consisting of moisture and greenness indices are less clear. Additionally, RS variables increase species‐ or functional type‐specific predictive power only modestly, and there are few clear links between the changes in RS variables and species or functional‐type occurrence and cover. We suggest that red and NIR reflectance can be used as satellite‐based indicators for peatland restoration success and further studies are required to develop usable methods for detecting species‐specific changes with RS.

Here we report on findings for four rock samples with melt texture found in a gravel pit within a glaciofluvial deposit near the small town of Kitkiöjärvi in northernmost Sweden. The samples are comprised of granitic clasts embedded in a brown fine‐grained melt matrix. The samples all contain quartz grains and/or clasts exhibiting multiple sets of planar deformation features oriented parallel to crystallographic planes characteristic of shock metamorphism. The samples also contain Former Reidite In Granular Neoblastic (FRIGN) zircon. We therefore conclude that the investigated samples represent impact melt rock. We interpret a U‐Pb concordia age of 658.9 ± 6.9 Ma (Cryogenian) derived using secondary‐ion mass spectrometry analysis of shocked zircon, as the best estimate for the age of the impact event that formed the melt rocks. Zircon grains from two of the samples yield younger lower intercept ages, raising the possibility that the samples came from multiple impact events of different ages. Although we cannot exclude this possibility, we interpret the younger ages from the clast‐rich melt rocks to reflect non‐impact‐related Pb loss events and suggest that all samples likely came from the same structure. Analysis of the glaciofluvial history of the region, along with the relatively high frequency of finds (five in total, as one similar melt rock was found in the pit in 2018), points to a short‐distance glacial transportation of the samples from the southwest. Since there are no known impact structures in Sweden within that area and/or of similar age, we conclude that an old (the oldest known yet) impact structure in Sweden potentially is yet to be discovered somewhere in the vicinity of the gravel pit.

The quarry landscapes of Virolahti, Uusikaupunki, and Vehmaa are results of quarry operations during the most important periods of natural stone quarrying in Finland. The quarry landscape in Virolahti was formed in connection to the quarrying of red Virolahti pyterlite for the construction of St. Petersburg in Russia from the middle of 1700s to the beginning of the 1900s, while in Uusikaupunki, the quarry landscape is connected to the start of the modern Finnish stone industry and the National Romantic architecture at the beginning of the 1900s. The quarry landscape in Vehmaa is related to the start of the modern Finnish stone industry and export of Finnish granite at the beginning of the 1900s. In Virolahti, several small quarries can be seen, while in Vehmaa, a tendency towards fewer, but larger quarries start to emerge. In each area, human settlement was formed around the quarries. The geological basis for all areas is a rock type suitable for natural stone quarrying. The geotechnical features of each rock type indicate high resistance to wear and the products from these areas are early examples of durable construction. The quarry landscapes represent well the typical quarrying technology of the time and its development from channelling by chisels through hand drilling to mechanical drilling and blasting. The quarry areas form unique industrial and cultural heritage landscapes in Finland.

Iron sulfide and metal melt veins in chondritic materials are associated with advanced stages of dynamic shock. The shock-induced residual temperatures liquefy thesulfide component and enable melt distribution. However, the distribution mechanism is not yet fully understood. Capillary forces are proposed as agents of melt distribution; yet, no laboratory experiments were conducted to assess the role that capillary forces play in the redistribution of iron sulfide in post-shock conditions. To investigate this further, we conducted thermal experiments under reducing conditions (N 2 (g)) using dunitic fragments, suitable chondritic analog materials that were doped with synthesized troilite (stoichiometric exact FeS). We observed extensive iron sulfide (troilite) migration that partially resembles that of ordinary chondrites, without the additional influence of shock pressure-induced fracturing. The iron sulfide melt infiltrated grain boundaries and pre-existing fractures that darkened the analog material pervasively. We also observed that the iron sulfide melt, which mobilized into grain boundaries, got systematically enriched in Ni from the surrounding host olivine. Consequently, FeNi metal fractionated from the melt in several places. Our results indicate that capillary forces majorly contribute to melt migration in the heated post-shock environment.

The continental bedrock contains groundwater-bearing fractures that are home to microbial populations that are vital in mediating the Earth’s biogeochemical cycles. However, their diversity is poorly understood due to the difficulty of obtaining samples from this environment. Here, a groundwater-bearing fracture at 975 m depth was isolated by employing packers in order to characterize the microbial community via metagenomes combined with prokaryotic and eukaryotic marker genes (16S and 18S ribosomal RNA gene). Genome-resolved analyses revealed a community dominated by sulfate-reducing Bacillota, predominantly represented by Candidatus Desulforudis audaxviator and with Wood-Ljungdahl as the most prevalent pathway for inorganic carbon fixation. Moreover, the eukaryotic community had a considerable diversity and was comprised of mainly flatworms, chlorophytes, crustaceans, ochrophytes, and fungi. These findings support the important role of the Bacillota, with the sulfate reducer Candidatus Desulforudis audaxviator as its main representative, as primary producers in the often energy-limited groundwaters of the continental subsurface.

Passive treatment of acid rock drainage (ARD) has been considered a sustainable approach in the long term, with sulfide inhibition by silica being a promising alternative. In a small-scale column leaching, a total of four cells loaded with pyritic waste rock (11 wt.% S) from an operating Cu mine in Sweden were kept in a climatic chamber at a controlled temperature and humidity. The waste rock was subjected to a water-leach for 11 weeks before treatment using alkaline silicate solution was applied, without pH buffer and adjuster. One cell was left untreated, whereas the others were treated with silicate solution as a source of dissolved silica, with and without H 2 O 2 pre-oxidation. The pH in silica-treated cells generated leachate with circumneutral pH until the end of the leaching cycle, whereas sulfide oxidation accelerated in the absence of treatment. Leachate quality in all Si-treated cells improved, as evidenced by the suppressed release of sulfur and other metals (e.g. Al, Fe, Cu, Co, Mn, and Ni). Silica (SiO 2 ) layer developed on waste rock upon treatment with a longer contact time, which remained stable upon extended exposure to air and water up to 10 weeks after treatment. Pyrite inhibition is attributed to the formation of silica layer. Despite forming a siliceous Fe-O phase, H 2 O 2 pre-oxidation resulted in indirect oxidation of sulfides and other phases. With an excess of silicate solution and at alkaline pH, pyrite surfaces are devoid of coating and metal ions were mobilized. Finally, this study suggested that treatment of pyritic waste rock using silica can attenuate ARD formation and prevent metal leaching by pyrite inhibition and maintaining a circumneutral pH environment or both.

High-quality maritime spatial planning, coastal zone management, management of marine resources, environmental assessments and forecasting require comprehensive understanding of the seabed. In response to the needs already in 2008, the European Commission established the European Marine Observation and Data Network (EMODnet). The EMODnet concept is to assemble existing but often fragmented and partly inaccessible marine data into harmonised, interoperable, and publicly freely available information layers which encompass whole marine basins. As the data products are free of restrictions on use the program is supporting any European maritime activities in promotion of sustainable use and management of the European seas. EMODnet-Geology project is delivering integrated geological map products which are aimed to be user friendly for public administration, research and education, maritime industry, and the general public.

Phytoplankton are the major primary producers in the pelagic system. They greatly influence biogeochemical cycles but little is known about the importance of shifting phytoplankton community composition for carbon dynamics. This study investigates the impact of seasonal changes in coastal phytoplankton communities on pelagic carbon fluxes. A field sampling campaign, covering an annual cycle in primary production, was conducted to assess the seasonal changes of phytoplankton communities and relevant organic carbon parameters in the coastal Baltic Sea. The monitoring frequency ranged from 1 to 3 wk, adapted to match the seasonal phytoplankton blooms. In addition, sediment traps were deployed to determine the particulate carbon and nutrient export to the seafloor in every season. We found that the phytoplankton biomass during the spring bloom was as high as 550 µg C l ⁻¹ and was dominated by diatom species (88% of total phytoplankton biomass). In comparison, the more species-rich summer bloom reached a combined maximum biomass of 236 µg C l ⁻¹ . However, the highest export flux of particulate organic carbon was found in the middle of August (561 mmol C m ⁻² d ⁻¹ ) and, not as expected, around the spring bloom in May (226 mmol C m ⁻² d ⁻¹ ), suggesting a high potential for carbon recycling within the pelagic food web rather than being exported to the seafloor or advected laterally. Our study emphasizes the importance of keystone species and diversity for carbon transport processes in marine coastal ecosystems and highlights complex relationships between phytoplankton biomass production, community composition and carbon dynamics.

The Rajapalot area of Finnish Lapland hosts an unusually high-grade association of cobalt-only and gold–cobalt deposits (10.91 Mt @ 2.5 g/t Au + 0.044% Co total inferred resources) within multiply folded metasedimentary rocks of the Paleoproterozoic Svecofennian collisional orogeny. Through the integration of X-ray computed micro-tomography and micro-X-ray fluorescence raster imaging of drill-core samples, we produce a model of cobalt-bearing ore mineralisation, which reveals primary fluid transportation mechanisms and precipitation pathways. When combined with the deposit-scale, high-resolution ground-based magnetic geophysical data, we show that cobalt-bearing ores in the Rajapalot region occur mostly as saddle reefs located in dilated fold hinges, which formed by simultaneous synthetic and antithetic shearing along developing crenulation-cleavage planes and incompetent bedding layers, respectively. We suggest that multi-layered rock complexes with alternations of competent and incompetent layers deformed and metamorphosed to upper greenschist-lower amphibolite facies should represent focus regions for cobalt exploration targeting campaigns in orogenic belts. The non-destructive workflow presented in this study could be an integral part of an early stage of cobalt mineral processing and traceability before metallurgical treatment.

As part of a recent mineral system study in the Metsämonttu–Aijala region in southern Finland, the Geological Survey of Finland (GTK) acquired an uncrewed aerial vehicle (UAV) magnetic survey to enhance geological interpretation of the area. The survey was conducted on a 25 km² are with 25 m line spacing. The data helped outline new bedrock observation and sampling sites and provides improved basis for the the construction of a revised bedrock map and structural model of the region.

The tectonic setting of Tonian orogenic events recorded in the present-day circum-North Atlantic region is uncertain. U-Pb zircon geochronology shows that the Yell Sound and Westings groups (Shetland) and metasedimentary rocks of the Naver Nappe (northern mainland Scotland) were deposited between c. 1050-960 Ma and intruded by mafic, intermediate and felsic igneous rocks at c. 965-950 Ma. Chemical discrimination diagrams and Hf and Nd isotope data together suggest that the protoliths of the mafic meta-igneous rocks were emplaced as relatively juvenile crustal contributions in an active plate margin. Zircon growth at c. 920 Ma within the Yell Sound Group correlates with high-grade metamorphism documented previously in Shetland. Further zircon growth and Pb-loss at c. 470-460 Ma indicates overprinting during the Ordovician Grampian orogenic event. Similar age successions of Ellesmere Island, Svalbard and East Greenland also contain evidence for Tonian magmatism (some calc-alkaline), deformation and metamorphism. The new data favour Rodinia reconstructions that incorporate subduction-related magmatism and associated tectonism along the margin of northeast Laurentia during the Tonian. The Yell Sound Group and correlative peri-Laurentian successions were intruded by subduction-related magmas and deformed and metamorphosed during development of the Valhalla exterior accretionary orogen, part of a more extensive peri-Rodinian subduction system.

Large amounts of slag are generated during pyrometallurgical processing in copper production. Due to the presence of valuable elements, the improper disposal of huge quantities of copper slag produced, results in significant loss of resources as well as environmental issues. Analyses of the copper slag show that it contains valuable metals, particularly copper and nickel. In this work, four biochars were employed as fossil-free reducing agents to recover valuable metals from the slag. Reduction experiments were performed in a vertical furnace at temperatures 1250, 1300 and 1350 °C for 60 min in order to investigate the effect of temperature. Moreover, the effect of time on reduction progress was studied at 1250 °C and the concentrations of CO and CO 2 in the off-gas were measured with a gas analyzer. Copper slag was reacted with metallurgical coke for comparison and the products were analyzed with EPMA and LA-ICPMS. The results revealed that reduction rapidly progresses to the formation of metal alloy within 10 min. Valuable metals like copper, nickel and arsenic were the first to be reduced to the metal phase. As reduction time increased, iron was also reduced and combined with the metal droplet. The use of biochar as reductant was shown to be more effective than coke especially at lower temperatures. In addition, thermodynamic modelling was performed with FactSage and HSC and compared with the experimental results. The simulations with HSC showed the sequence of reactions taking place and the calculations by FactSage were in agreement with the experiments. Graphical Abstract