S. Karvinen, A. Heinonen, Christoph Beier, Niels Jöns
We present a geochemical dataset and cathodoluminescence images of apatite from the Neoarchean (2610 Ma) glimmerite-carbonatite rocks from the Siilinjärvi complex, Eastern Finland. The subhedral, tapered prismatic grains are compositionally fluorapatite, with limited substitution of Ca by Sr, Na and low REE and Si contents. The Sr/Y ratios are among the highest in a global apatite comparison, comparable to those from other calcite carbonatites, dolomite carbonatites, and phoscorites. Some grains show evidence of late- or post-magmatic interaction with a carbonatite magma or a hydrothermal fluid, resulting in REE-rich overgrowth rims or recrystallized grains with abundant fluid inclusions. We interpret the high Sr/Y ratios combined with low REE contents and depleted heavy REE+Y to represent crystallization from a mantle-derived carbonatite parental magma. We show that the Siilinjärvi apatite is chemically heterogeneous but with a limited range in compositions. There are noticeable compositional differences on all spatial scales from micrometer to tens of meters, i.e., within a single crystal, between crystals in a sample, between samples and the two individual sampling locations. We conclude that the intra-crystal geochemical variability in apatite is a suitable tracer of the magmatic and post-magmatic evolution of carbonatite complexes.
{"title":"The composition of apatite in the Archean Siilinjärvi glimmerite-carbonatite complex in eastern Finland","authors":"S. Karvinen, A. Heinonen, Christoph Beier, Niels Jöns","doi":"10.17741/bgsf/96.1.001","DOIUrl":"https://doi.org/10.17741/bgsf/96.1.001","url":null,"abstract":"We present a geochemical dataset and cathodoluminescence images of apatite from the Neoarchean (2610 Ma) glimmerite-carbonatite rocks from the Siilinjärvi complex, Eastern Finland. The subhedral, tapered prismatic grains are compositionally fluorapatite, with limited substitution of Ca by Sr, Na and low REE and Si contents. The Sr/Y ratios are among the highest in a global apatite comparison, comparable to those from other calcite carbonatites, dolomite carbonatites, and phoscorites. Some grains show evidence of late- or post-magmatic interaction with a carbonatite magma or a hydrothermal fluid, resulting in REE-rich overgrowth rims or recrystallized grains with abundant fluid inclusions. We interpret the high Sr/Y ratios combined with low REE contents and depleted heavy REE+Y to represent crystallization from a mantle-derived carbonatite parental magma. We show that the Siilinjärvi apatite is chemically heterogeneous but with a limited range in compositions. There are noticeable compositional differences on all spatial scales from micrometer to tens of meters, i.e., within a single crystal, between crystals in a sample, between samples and the two individual sampling locations. We conclude that the intra-crystal geochemical variability in apatite is a suitable tracer of the magmatic and post-magmatic evolution of carbonatite complexes.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363824","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}
Evgeniya Sidkina, Evgeniya Soldatova, Elena Cherkasova, Artem Konyshev, Andrey Toropov, Sofia Vorobey, Mikhail Mironenko
The Beck mine, located in the Republic of Karelia, Russia, is an abandoned mining site with significant potential for environmental contamination due to the presence of potential pollutants in its waste rocks. In this study, we investigated the chemical composition of mine waters and waste rocks and developed a theoretical model to understand waterrock interactions and the release of potential pollutants. Water samples collected from various locations on the Beck mine property were analyzed for chemical composition and showed low concentrations of total dissolved solids with pH values ranging from 6.42 to 7.74. The chemical composition of natural waters was determined by ICP-MS, ICP-AES, ion chromatography, potentiometric titration, and spectrophotometry. Equilibrium kinetic modeling was used to simulate water-rock interactions. The model predicted the concentrations of major and trace elements, demonstrating that dissolutionprecipitation and complexation are the primary mechanisms shaping the chemical composition of mine waters. The dynamics of dissolution-precipitation of Fe-containing minerals highlighted the importance of the duration of water-rock interaction, with stagnant mine waters exhibiting higher concentrations of heavy metals. In addition, the presence of dissolved organic matter played a critical role in the accumulation of iron and arsenic in the studied mine waters. Overall, this study highlights the utility of equilibrium kinetic modeling in understanding the behavior of heavy metals during water-rock interactions and provides valuable insights into the potential environmental impacts of abandoned mine sites such as the Beck mine.
{"title":"Predicting potential pollutant release from waste rock at the abandoned Beck mine (Karelia, Russia) by equilibrium kinetic modeling","authors":"Evgeniya Sidkina, Evgeniya Soldatova, Elena Cherkasova, Artem Konyshev, Andrey Toropov, Sofia Vorobey, Mikhail Mironenko","doi":"10.17741/bgsf/96.1.004","DOIUrl":"https://doi.org/10.17741/bgsf/96.1.004","url":null,"abstract":"The Beck mine, located in the Republic of Karelia, Russia, is an abandoned mining site with significant potential for environmental contamination due to the presence of potential pollutants in its waste rocks. In this study, we investigated the chemical composition of mine waters and waste rocks and developed a theoretical model to understand waterrock interactions and the release of potential pollutants. Water samples collected from various locations on the Beck mine property were analyzed for chemical composition and showed low concentrations of total dissolved solids with pH values ranging from 6.42 to 7.74. The chemical composition of natural waters was determined by ICP-MS, ICP-AES, ion chromatography, potentiometric titration, and spectrophotometry. Equilibrium kinetic modeling was used to simulate water-rock interactions. The model predicted the concentrations of major and trace elements, demonstrating that dissolutionprecipitation and complexation are the primary mechanisms shaping the chemical composition of mine waters. The dynamics of dissolution-precipitation of Fe-containing minerals highlighted the importance of the duration of water-rock interaction, with stagnant mine waters exhibiting higher concentrations of heavy metals. In addition, the presence of dissolved organic matter played a critical role in the accumulation of iron and arsenic in the studied mine waters. Overall, this study highlights the utility of equilibrium kinetic modeling in understanding the behavior of heavy metals during water-rock interactions and provides valuable insights into the potential environmental impacts of abandoned mine sites such as the Beck mine.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363353","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}
A widely spread ridge relief complex was formed by the last ice cover in the northeastern part of the Kola Peninsula. The complex belongs to the ice-marginal formations of the ice streams of the north-eastern Fennoscandian Ice Sheet. The applied morphometric research technique (including the analysis of the digital elevation model) has allowed identifying the ridge relief complex to make a sub-longitudinal belt. The belt comprises frontal and radial ridges, ridges and hills of the distal part of the belt, and complex-shaped ridges. These landforms were studied in eight outcrops and trenches. The frontal and some complex-shaped ridges consist of basal and ablation tills and glaciofluvial deposits deformed by the east- and north-eastward advancing glacier. The radial ridges composed of glaciofluvial sediments are the eskers. Glaciofluvial deposits with a thin cover of ablation and flow tills form the ridges on the distal part of the belt. They mark the limits of glacier expansion at an individual glacial stage. Some complex-shaped ridges are composed only of the ablation melt-out till and formed in crevasses of dead ice massifs. The ridge relief complex shows morphological similarities with the Veiki moraine in North Sweden, Pulju moraine in Finland, and ridges of the “ice-walled-lake plains” in North America. The location of the moraine ridge landforms is controlled by the topography of crystalline bedrock. During the last glaciation, the glacier retreated in several stages marked by belts of the ridge landforms. Each stage was followed by a series of oscillations corresponding to chains of frontal moraine ridges. The correlation of the ice-marginal forms in other parts of the Kola and Karelia regions allows the authors to refer them to the Neva Stage (other names are Keiva I, Syamozero), which took place in the Older Dryas Stadial.
{"title":"Ice-marginal ridge relief complex in northern Kola Peninsula (NW Russia): morphology, structure, and genetic interpretation","authors":"A. Vashkov, O. Nosova","doi":"10.17741/bgsf/96.1.002","DOIUrl":"https://doi.org/10.17741/bgsf/96.1.002","url":null,"abstract":"A widely spread ridge relief complex was formed by the last ice cover in the northeastern part of the Kola Peninsula. The complex belongs to the ice-marginal formations of the ice streams of the north-eastern Fennoscandian Ice Sheet. The applied morphometric research technique (including the analysis of the digital elevation model) has allowed identifying the ridge relief complex to make a sub-longitudinal belt. The belt comprises frontal and radial ridges, ridges and hills of the distal part of the belt, and complex-shaped ridges. These landforms were studied in eight outcrops and trenches. The frontal and some complex-shaped ridges consist of basal and ablation tills and glaciofluvial deposits deformed by the east- and north-eastward advancing glacier. The radial ridges composed of glaciofluvial sediments are the eskers. Glaciofluvial deposits with a thin cover of ablation and flow tills form the ridges on the distal part of the belt. They mark the limits of glacier expansion at an individual glacial stage. Some complex-shaped ridges are composed only of the ablation melt-out till and formed in crevasses of dead ice massifs. The ridge relief complex shows morphological similarities with the Veiki moraine in North Sweden, Pulju moraine in Finland, and ridges of the “ice-walled-lake plains” in North America. The location of the moraine ridge landforms is controlled by the topography of crystalline bedrock. During the last glaciation, the glacier retreated in several stages marked by belts of the ridge landforms. Each stage was followed by a series of oscillations corresponding to chains of frontal moraine ridges. The correlation of the ice-marginal forms in other parts of the Kola and Karelia regions allows the authors to refer them to the Neva Stage (other names are Keiva I, Syamozero), which took place in the Older Dryas Stadial.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362977","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}
Four quartz monzonite – granite intrusions forming the Sorsakoski granite lithodeme, are found within the Raahe-Ladoga suture zone in Central Finland. The prevailing potassium feldspar megacrystic quartz monzonites and granites form a bimodal association with diorites and gabbros. The granitoids are mainly calc-alkaline, ferroan, per- to metaluminous, and have high Zr and REE contents. Dominant mafic minerals are biotite and hornblende, clinopyroxene and orthopyroxene are locally present. The mafic units display effects of fractionation of clinopyroxene. In our interpretation, these intrusions were emplaced during regional late stages of deformation and post-crystallisation deformation partitioned into major shear zones leaving bulk of the intrusions relatively undeformed. Based on one new (1876 ± 6 Ma) and one pre-existing (1882 ± 5 Ma) U-Pb zircon age determination, the crystallisation age of the granitoids can be assumed at ca. 1880 Ma. Based on mineralogy, petrography, geochemistry, bimodal nature of magmatism and age, we correlate these intrusions to the A-type rocks of the previously described Saarijärvi suite. This shows that the syn-orogenic A-type magmatism extended eastwards beyond the Central Finland Granitoid Complex.
在芬兰中部的拉赫-拉多加缝合带中发现了四个石英单斜岩-花岗岩侵入体，形成了索萨科斯基花岗岩岩系。主要的钾长石巨晶石英单长岩和花岗岩与闪长岩和辉长岩形成双峰组合。花岗岩主要为钙碱性、铁质、过铝质到金属铝质，锆和稀土元素含量较高。主要的黑云母矿物是黑云母和角闪石，局部存在霞石和正长石。黑云母单元显示了霞石的分馏效应。根据我们的解释，这些侵入体是在区域变形晚期阶段形成的，结晶后变形分为主要剪切带，侵入体的大部分相对未变形。根据一次新的（1876 ± 6 Ma）和一次已有的（1882 ± 5 Ma）U-Pb锆石年龄测定，花岗岩的结晶年龄可推定为约1880 Ma。1880 Ma。根据矿物学、岩相学、地球化学、岩浆作用的双峰性质和年龄，我们将这些侵入体与之前描述的 Saarijärvi 岩石群的 A 型岩石相关联。这表明，同步成因的 A 型岩浆活动向东延伸到了芬兰中部花岗岩群之外。
{"title":"1.88 Ga granitoids at Sorsakoski, Central Finland: A-type magmatism within the Raahe-Ladoga suture zone","authors":"Perttu Mikkola, Maija Pietilä, T. Rämö, H. Huhma","doi":"10.17741/bgsf/96.1.003","DOIUrl":"https://doi.org/10.17741/bgsf/96.1.003","url":null,"abstract":"Four quartz monzonite – granite intrusions forming the Sorsakoski granite lithodeme, are found within the Raahe-Ladoga suture zone in Central Finland. The prevailing potassium feldspar megacrystic quartz monzonites and granites form a bimodal association with diorites and gabbros. The granitoids are mainly calc-alkaline, ferroan, per- to metaluminous, and have high Zr and REE contents. Dominant mafic minerals are biotite and hornblende, clinopyroxene and orthopyroxene are locally present. The mafic units display effects of fractionation of clinopyroxene. In our interpretation, these intrusions were emplaced during regional late stages of deformation and post-crystallisation deformation partitioned into major shear zones leaving bulk of the intrusions relatively undeformed. Based on one new (1876 ± 6 Ma) and one pre-existing (1882 ± 5 Ma) U-Pb zircon age determination, the crystallisation age of the granitoids can be assumed at ca. 1880 Ma. Based on mineralogy, petrography, geochemistry, bimodal nature of magmatism and age, we correlate these intrusions to the A-type rocks of the previously described Saarijärvi suite. This shows that the syn-orogenic A-type magmatism extended eastwards beyond the Central Finland Granitoid Complex.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141366572","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}
Peter Edén, A. Boman, Stefan Mattbäck, J. Auri, M. Yli-Halla, P. Österholm
Acid sulfate soils (ASS) cause big problems worldwide due to their potential to form sulfuric acid during oxidation of sulfidic materials, resulting in very acid soil (pH <4.0). Impacts include acidification of soil and water, leaching of metals, decreased nutrient supply, deterioration of water fauna and flora, and corrosion of infrastructure. These soils also exhibit poor geotechnical properties. Finland has the largest occurrences of ASS in Europe, mainly along the coast of the Baltic Sea. The EU Water Framework Directive brought about wide co-operation to reduce the harmful impacts of ASS in Finland. One urgent step was to localize and characterize the occurrences of ASS. The more than 10 year-long programme, led by the Geological Survey of Finland (GTK), started in 2009 and field work was completed in 2021. During the programme observations, measurements, sampling and analyses were made at 23 000 sites in an area of 5 010 000 ha. Traditionally ASS in Finland have been considered to comprise fine-grained sulfidic sediments and/or their oxidized layers, occurring on agricultural land along the coast below the highest shoreline of the Littorina Sea transgression. This study recognized and classified significant occurrences of other types of potentially harmful ASS materials: (1) coarse-grained ASS (sand), (2) organic ASS (peat) and (3) unsorted ASS (till material). The methods, definition and classification of Finnish ASS have been revised. We calculated the extent of ASS along the coast to be about 1 000 000 ha corresponding to 21% of the area covered in the past by the Littorina Sea, and three to six times more than earlier estimates. In addition, some occurrences of ASS were recognized inland, mainly related to black shales and sulfidic ores. The mapping data can be accessed via the GTK map service (www.gtk.fi) providing information about the distribution and properties of ASS.
酸性硫酸盐土壤（ASS）会在含硫物质氧化过程中形成硫酸，导致土壤酸度极高（pH 值小于 4.0），从而在全球范围内造成严重问题。其影响包括土壤和水的酸化、金属的沥滤、养分供应的减少、水生动植物的退化以及基础设施的腐蚀。这些土壤的岩土特性也很差。芬兰是欧洲 ASS 分布最多的国家，主要分布在波罗的海沿岸。欧盟水框架指令》促使各方广泛合作，以减少 ASS 对芬兰的有害影响。当务之急是确定 ASS 的分布地点和特征。由芬兰地质调查局（GTK）领导的这项长达 10 多年的计划于 2009 年启动，实地工作于 2021 年完成。计划期间，在 5 010 000 公顷面积上的 23 000 个地点进行了观察、测量、取样和分析。传统上，芬兰的 ASS 被认为由细粒硫酸盐沉积物和/或其氧化层组成，出现在利托里纳海横断面最高海岸线以下沿岸的农田中。这项研究确认了其他类型潜在有害 ASS 物质的大量出现，并对其进行了分类：(1) 粗粒 ASS（沙），(2) 有机 ASS（泥炭）和 (3) 未分类 ASS（耕层物质）。我们对芬兰 ASS 的方法、定义和分类进行了修订。根据我们的计算，沿岸的 ASS 面积约为 1 000 000 公顷，相当于过去利托里纳海覆盖面积的 21%，是之前估计的 3 到 6 倍。此外，内陆也发现了一些 ASS，主要与黑色页岩和硫化矿有关。绘图数据可通过 GTK 地图服务（www.gtk.fi）访问，提供有关 ASS 分布和特性的信息。
{"title":"Mapping, impacts, characterization and extent of acid sulfate soils in Finland","authors":"Peter Edén, A. Boman, Stefan Mattbäck, J. Auri, M. Yli-Halla, P. Österholm","doi":"10.17741/bgsf/95.2.003","DOIUrl":"https://doi.org/10.17741/bgsf/95.2.003","url":null,"abstract":"Acid sulfate soils (ASS) cause big problems worldwide due to their potential to form sulfuric acid during oxidation of sulfidic materials, resulting in very acid soil (pH <4.0). Impacts include acidification of soil and water, leaching of metals, decreased nutrient supply, deterioration of water fauna and flora, and corrosion of infrastructure. These soils also exhibit poor geotechnical properties. Finland has the largest occurrences of ASS in Europe, mainly along the coast of the Baltic Sea. The EU Water Framework Directive brought about wide co-operation to reduce the harmful impacts of ASS in Finland. One urgent step was to localize and characterize the occurrences of ASS. The more than 10 year-long programme, led by the Geological Survey of Finland (GTK), started in 2009 and field work was completed in 2021. During the programme observations, measurements, sampling and analyses were made at 23 000 sites in an area of 5 010 000 ha. Traditionally ASS in Finland have been considered to comprise fine-grained sulfidic sediments and/or their oxidized layers, occurring on agricultural land along the coast below the highest shoreline of the Littorina Sea transgression. This study recognized and classified significant occurrences of other types of potentially harmful ASS materials: (1) coarse-grained ASS (sand), (2) organic ASS (peat) and (3) unsorted ASS (till material). The methods, definition and classification of Finnish ASS have been revised. We calculated the extent of ASS along the coast to be about 1 000 000 ha corresponding to 21% of the area covered in the past by the Littorina Sea, and three to six times more than earlier estimates. In addition, some occurrences of ASS were recognized inland, mainly related to black shales and sulfidic ores. The mapping data can be accessed via the GTK map service (www.gtk.fi) providing information about the distribution and properties of ASS.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472131","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}
Metasedimentary rocks from nine sampling sites in southern Finland and an intermediate dyke in one of these sites were sampled for analysis of U–Pb zircon age and geochemical composition. The zircons of the metasedimentary rock samples yield 207Pb/206Pb dates ranging from 3281 to 1810 Ma. The nearly concordant dates from apparent detrital zircon cores indicate a prominent source with age around 2.1–2.0 Ga. The maximum depositional ages estimated for six of the metasedimentary rock samples span from 1.96 to 1.89 Ga. The data from zircon rims and overgrowths and metamorphic zircons in the metasedimentary rock samples indicate regional metamorphic events in the study area at least at ca. 1.89 and 1.84 Ga, and possibly also at ca. 1.87 Ga. The minimum age of the deposition (≤1.89 Ga) was estimated based on the ages of the regional metamorphism and the intrusive rocks. Some zircon rims and overgrowths yield ≥1.91 Ga 207Pb/206Pb dates, which are considered to possibly represent metamorphic events in the source areas.
对芬兰南部九个采样点的沉积岩和其中一个采样点的中间堤坝进行了采样，以分析 U-Pb 锆石年龄和地球化学成分。沉积岩样本的锆石得出的 207Pb/206Pb 时间范围为 3281 至 1810 Ma。来自表观碎屑锆石岩心的近乎一致的年代表明了一个年龄约为 2.1-2.0 Ga 的突出来源。六个变质岩样本的最大沉积年龄估计在 1.96 至 1.89 Ga 之间。变质岩样本中的锆石边缘和覆盖层以及变质锆石的数据表明，研究区域至少在约 1.89 和 1.84 Ga 发生过区域变质事件。1.89和1.84 Ga，也可能是在约1.87 Ga。1.87 Ga。沉积的最小年龄（≤1.89 Ga）是根据区域变质作用和侵入岩的年龄估算出来的。一些锆石边缘和覆盖层的 207Pb/206Pb 时间≥1.91 Ga，被认为可能代表了源区的变质事件。
{"title":"New age constraints for metasedimentary rocks in southern Finland","authors":"Paula Salminen, M. Kurhila","doi":"10.17741/bgsf/95.2.001","DOIUrl":"https://doi.org/10.17741/bgsf/95.2.001","url":null,"abstract":"Metasedimentary rocks from nine sampling sites in southern Finland and an intermediate dyke in one of these sites were sampled for analysis of U–Pb zircon age and geochemical composition. The zircons of the metasedimentary rock samples yield 207Pb/206Pb dates ranging from 3281 to 1810 Ma. The nearly concordant dates from apparent detrital zircon cores indicate a prominent source with age around 2.1–2.0 Ga. The maximum depositional ages estimated for six of the metasedimentary rock samples span from 1.96 to 1.89 Ga. The data from zircon rims and overgrowths and metamorphic zircons in the metasedimentary rock samples indicate regional metamorphic events in the study area at least at ca. 1.89 and 1.84 Ga, and possibly also at ca. 1.87 Ga. The minimum age of the deposition (≤1.89 Ga) was estimated based on the ages of the regional metamorphism and the intrusive rocks. Some zircon rims and overgrowths yield ≥1.91 Ga 207Pb/206Pb dates, which are considered to possibly represent metamorphic events in the source areas.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140477109","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}
V. Järvinen, Nikolaos Karampelas, T. Rämö, T. Halkoaho, Tuomo Törmänen, Perttu Mikkola, Y. Lahaye
The target of this study is the Takanen greenstone belt (TGB), a small 11-km-long and east-west oriented supracrustal belt in the northern Lentua complex of the Western Karelia Subprovince (eastern Finland). We present a new geological interpretation of the TGB based on lithology, geochemistry, stratigraphy, and two new zircon U-Pb age determinations and Lu-Hf-in-zircon data. The TGB forms a ���≥800-m-thick synclinal sequence composed of intercalated mafic-���komatiitic and felsic-intermediate volcanic and volcaniclastic rocks (lavas, tuffs, and tuffites) crosscut by granitoid dykes, and metamorphosed in lower amphibolite facies with few primary volcanic textures visible. The felsic-intermediate rocks are calc-alkaline and split into strongly and weakly REE-fractionated groups. The mafic-ultramafic rocks are tholeiitic with flat REE-patterns, but some samples show LREE-enrichment. Massive Fe-sulfide layers (≤��1 m) are associated with volcanoclastic rocks. Komatiites are Al-undepleted and comprise differentiated (peridotite-gabbro) and undifferentiated (dunite/serpentinite) cumulates and thin undifferentiated flows. Channel-facies komatiitic cumulates are found stratigraphically above Fe-sulfide-rich unites and have �potential for komatiite-hosted Ni-deposits. Our new isotope data from two felsic-intermediate volcanic rock samples shows that the TGBs stratigraphically lowermost and uppermost units are 2.96 Ga and 2.71 Ga old, respectively. Based on Hf isotope data, the older 2.96 Ga sample contains reworked crustal material, possibly originating from ~3.2 Ga crust.In contrast, the 2.71 Ga sample is isotopically juvenile (near-chondritic), indicating an episode of juvenile crust formation in the northern Lentua Complex. No unconformity is found between the stratigraphically upper and lower parts of the TGB, but the ~250 Ma age difference (and geochemical indicators) suggests they may have formed in different tectonic settings. The lower part of TGB stratigraphy is correlated with the ~2.94 Ga Luoma Formation in the nearby Suomussalmi greenstone belt. The 2.71 Ga volcanic unit does not have a known equivalent in greenstone belts in Finland, but a corollary is found in Russia, and a tentative correlation to a possible 2.75–2.70 Ga arc-system in Takanen–Khedozero-Bolshozero–Ilomantsi is suggested.
本研究的目标是塔卡嫩绿岩带（TGB），它是西卡累利阿分省（芬兰东部）北部伦图亚复合体中的一个东西走向、长 11 千米的小型超地壳带。我们基于岩石学、地球化学、地层学以及两个新的锆石U-Pb年龄测定和锆石中的Lu-Hf数据，对TGB提出了新的地质解释。TGB形成了厚度≥800米的同向层序，由夹杂的黑云母质和长英质中火山岩和火山碎屑岩（熔岩、凝灰岩和凝灰岩）组成，并被花岗岩岩体横切，变质为下闪长岩面，几乎看不到原生火山岩纹理。长岩-中岩为钙碱性，分为强稀土元素分馏组和弱稀土元素分馏组。黑云母-超黑云母岩为托勒密岩，REE形态平缓，但部分样本显示出LREE富集。大量硫化铁层（≤1 米）与火山碎屑岩有关。孔雀石是铝贫化岩，由分化（橄榄岩-辉长岩）和未分化（云英岩/蛇绿岩）的积岩以及薄的未分化流体组成。在富含硫化铁的单元地层之上发现了槽阶孔黝帘石堆积物，具有孔黝帘石寄生镍矿床的潜力。我们从两个长英质-中英质火山岩样本中获得的新同位素数据显示，TGBs地层最下和最上单元的年龄分别为2.96 Ga和2.71 Ga。根据 Hf 同位素数据，较早的 2.96 Ga 样本含有再加工的地壳物质，可能来自 ~3.2 Ga 的地壳。相反，2.71 Ga 样本在同位素上是幼年的（近软玉质），表明在 Lentua 复合体北部曾有过幼年地壳形成。TGB地层上部和下部之间没有发现不整合现象，但约250 Ma的年龄差异（以及地球化学指标）表明它们可能是在不同的构造环境中形成的。TGB地层的下部与附近苏奥穆萨尔米绿岩带的约2.94 Ga的Luoma地层相关。2.71 Ga火山岩单元在芬兰的绿岩带中没有已知的对应单元，但在俄罗斯发现了一个相应单元，并提出了与Takanen-Khedozero-Bolshozero-Ilomantsi可能的2.75-2.70 Ga弧系统的初步相关性。
{"title":"Secular change of tectonic setting in the Archean Takanen greenstone belt, northeastern Karelia Province, Fennoscandian Shield","authors":"V. Järvinen, Nikolaos Karampelas, T. Rämö, T. Halkoaho, Tuomo Törmänen, Perttu Mikkola, Y. Lahaye","doi":"10.17741/bgsf/95.2.002","DOIUrl":"https://doi.org/10.17741/bgsf/95.2.002","url":null,"abstract":"The target of this study is the Takanen greenstone belt (TGB), a small 11-km-long and east-west oriented supracrustal belt in the northern Lentua complex of the Western Karelia Subprovince (eastern Finland). We present a new geological interpretation of the TGB based on lithology, geochemistry, stratigraphy, and two new zircon U-Pb age determinations and Lu-Hf-in-zircon data. The TGB forms a ���≥800-m-thick synclinal sequence composed of intercalated mafic-���komatiitic and felsic-intermediate volcanic and volcaniclastic rocks (lavas, tuffs, and tuffites) crosscut by granitoid dykes, and metamorphosed in lower amphibolite facies with few primary volcanic textures visible. The felsic-intermediate rocks are calc-alkaline and split into strongly and weakly REE-fractionated groups. The mafic-ultramafic rocks are tholeiitic with flat REE-patterns, but some samples show LREE-enrichment. Massive Fe-sulfide layers (≤��1 m) are associated with volcanoclastic rocks. Komatiites are Al-undepleted and comprise differentiated (peridotite-gabbro) and undifferentiated (dunite/serpentinite) cumulates and thin undifferentiated flows. Channel-facies komatiitic cumulates are found stratigraphically above Fe-sulfide-rich unites and have �potential for komatiite-hosted Ni-deposits. Our new isotope data from two felsic-intermediate volcanic rock samples shows that the TGBs stratigraphically lowermost and uppermost units are 2.96 Ga and 2.71 Ga old, respectively. Based on Hf isotope data, the older 2.96 Ga sample contains reworked crustal material, possibly originating from ~3.2 Ga crust.In contrast, the 2.71 Ga sample is isotopically juvenile (near-chondritic), indicating an episode of juvenile crust formation in the northern Lentua Complex. No unconformity is found between the stratigraphically upper and lower parts of the TGB, but the ~250 Ma age difference (and geochemical indicators) suggests they may have formed in different tectonic settings. The lower part of TGB stratigraphy is correlated with the ~2.94 Ga Luoma Formation in the nearby Suomussalmi greenstone belt. The 2.71 Ga volcanic unit does not have a known equivalent in greenstone belts in Finland, but a corollary is found in Russia, and a tentative correlation to a possible 2.75–2.70 Ga arc-system in Takanen–Khedozero-Bolshozero–Ilomantsi is suggested.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140471659","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}
A. Boman, Stefan Mattbäck, Marina Becher, M. Yli-Halla, Gustav Sohlenius, J. Auri, Christian Öhrling, Pauliina Liwata-Kenttälä, Peter Edén
Established international soil classification systems have not properly accommodated acid sulfate soils (ASS) and soil materials in Finland and Sweden because: (1) in these soils some diagnostic ASS properties are too deep to meet the depth requirements, and (2) there is a lack of defined diagnostic soil classification criteria for acidic and potentially acidic soil materials that do not completely fulfill the diagnostic pH-criterion of pH < 4.0. In this paper, two new ASS materials are introduced with the prefix “para” for parasulfuric material (oxidized material) and parahypersulfidic material (reduced material). These materials have diagnostic pH-criteria of pH 4.0–4.5 and 3.0–3.5 (field-pH for parasulfuric material and incubation-pH for parahypersulfidic material) for mineral and organic soil materials (here defined as > 20% organic matter; peat and gyttja), respectively. The term “para-acid sulfate soil (para-ASS) material” is introduced for soil materials which may have a considerable environmental impact due to mobilization of acidity and dissolved metals. Because organic acids may lower pH to values below the established pH-value of < 4.0 for ASS materials, a pH of < 3.0 is used in the Finnish-Swedish ASS classification for organic soil materials. These changes and new additions to existing diagnostic ASS materials have consequently also led to a slight modification of the required field-pH values of the existing terms “hypersulfidic material” and “sulfuric material”. The Finnish-Swedish ASS classification further includes a systematic way for classification of the entire soil profile and no depth requirements for diagnostic ASS materials are present; what matters is the current or potential environmental impact that the soil has or may have. It is proposed that the Finnish-Swedish ASS classification may serve as a framework for establishing a unified ASS classification globally and that the new diagnostic ASS materials are included in relevant international soil classification systems.
既有的国际土壤分类系统并不能很好地适应芬兰和瑞典的酸性硫酸盐土壤（ASS）和土壤材料，这是因为：（1）在这些土壤中，一些诊断性 ASS 属性的深度太深，无法满足深度要求；（2）对于酸性和潜在酸性土壤材料，缺乏明确的诊断性土壤分类标准，这些材料并不完全符合 pH < 4.0 的诊断性 pH 标准。本文介绍了两种新的 ASS 材料，前缀 "para "分别代表副硫酸盐材料（氧化材料）和副过硫酸盐材料（还原材料）。这些材料对矿物和有机土壤材料（此处定义为有机物含量大于 20%；泥炭和石膏）的 pH 值诊断标准分别为 4.0-4.5 和 3.0-3.5（副硫酸盐材料的现场 pH 值和副过硫酸盐材料的培养 pH 值）。术语 "对位酸性硫酸盐土壤（para-ASS）材料 "指的是由于酸性和溶解金属的移动而可能对环境产生重大影响的土壤材料。由于有机酸可将 pH 值降至低于 ASS 材料的既定 pH 值 < 4.0，因此芬兰-瑞典 ASS 分类法中有机土壤材料的 pH 值为 < 3.0。因此，这些变化和对现有 ASS 材料诊断的新增加，也导致对现有术语 "高硫酸盐材料 "和 "硫酸盐材料 "所要求的现场 pH 值进行了轻微修改。芬兰-瑞典 ASS 分类法还包括对整个土壤剖面进行系统分类的方法，对诊断性 ASS 材料没有深度要求；重要的是土壤目前或可能对环境造成的影响。建议将芬兰-瑞典 ASS 分类法作为建立全球统一 ASS 分类法的框架，并将新的诊断性 ASS 材料纳入相关的国际土壤分类系统。
{"title":"Classification of acid sulfate soils and soil materials in Finland and Sweden: Re-introduction of para-acid sulfate soils","authors":"A. Boman, Stefan Mattbäck, Marina Becher, M. Yli-Halla, Gustav Sohlenius, J. Auri, Christian Öhrling, Pauliina Liwata-Kenttälä, Peter Edén","doi":"10.17741/bgsf/95.2.004","DOIUrl":"https://doi.org/10.17741/bgsf/95.2.004","url":null,"abstract":"Established international soil classification systems have not properly accommodated acid sulfate soils (ASS) and soil materials in Finland and Sweden because: (1) in these soils some diagnostic ASS properties are too deep to meet the depth requirements, and (2) there is a lack of defined diagnostic soil classification criteria for acidic and potentially acidic soil materials that do not completely fulfill the diagnostic pH-criterion of pH < 4.0. In this paper, two new ASS materials are introduced with the prefix “para” for parasulfuric material (oxidized material) and parahypersulfidic material (reduced material). These materials have diagnostic pH-criteria of pH 4.0–4.5 and 3.0–3.5 (field-pH for parasulfuric material and incubation-pH for parahypersulfidic material) for mineral and organic soil materials (here defined as > 20% organic matter; peat and gyttja), respectively. The term “para-acid sulfate soil (para-ASS) material” is introduced for soil materials which may have a considerable environmental impact due to mobilization of acidity and dissolved metals. Because organic acids may lower pH to values below the established pH-value of < 4.0 for ASS materials, a pH of < 3.0 is used in the Finnish-Swedish ASS classification for organic soil materials. These changes and new additions to existing diagnostic ASS materials have consequently also led to a slight modification of the required field-pH values of the existing terms “hypersulfidic material” and “sulfuric material”. The Finnish-Swedish ASS classification further includes a systematic way for classification of the entire soil profile and no depth requirements for diagnostic ASS materials are present; what matters is the current or potential environmental impact that the soil has or may have. It is proposed that the Finnish-Swedish ASS classification may serve as a framework for establishing a unified ASS classification globally and that the new diagnostic ASS materials are included in relevant international soil classification systems.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140478000","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}
Mining industry generates a significant amount of waste including waste rock and tailings. The disposal of mine tailings has environmental impacts, such as the releasing of heavy metals to surface and underground waters. Therefore, adequate rehabilitation of mining waste storage facilities is essential. Abandoned tailings ponds may contain significant amounts of valuable minerals, including critical raw materials, and offer opportunities as secondary mineral resources. In this study geochemical and mineralogical characterization were made for the diverse mine tailings of the Rautuvaara tailings pond which was the final disposal site for different ore deposits. The samples were collected from two different locations in the tailings pond, preconcentrated and analysed with several methods including PSA, XRD, FE-SEM, EPMA, pXRF, WD-XRF and AAS. The geochemical results indicate substantially elevated Cu, As, Ni and Zn concentrations in the tailings. Mineralogical investigations revealed that the tailings contain valuable minerals such as gold, cobaltite, and W-bearing rutile. The last could be used as an indicator mineral in tailings classification and possibly also in future ore exploration. The study of secondary mineralogy revealed that the most weathered top layers of the tailings show secondary alteration rims on the surfaces of mineral particles, and the enrichment of As and Ni in the Fe- and Mn-oxide minerals.
{"title":"Geochemical and mineralogical characterization of mine tailings at the Rautuvaara mine site and aspects to environmental conditions and resource potential","authors":"Mitro Juutinen, Markku Seitsaari, P. Sarala","doi":"10.17741/bgsf/95.1.005","DOIUrl":"https://doi.org/10.17741/bgsf/95.1.005","url":null,"abstract":"Mining industry generates a significant amount of waste including waste rock and tailings. The disposal of mine tailings has environmental impacts, such as the releasing of heavy metals to surface and underground waters. Therefore, adequate rehabilitation of mining waste storage facilities is essential. Abandoned tailings ponds may contain significant amounts of valuable minerals, including critical raw materials, and offer opportunities as secondary mineral resources. In this study geochemical and mineralogical characterization were made for the diverse mine tailings of the Rautuvaara tailings pond which was the final disposal site for different ore deposits. The samples were collected from two different locations in the tailings pond, preconcentrated and analysed with several methods including PSA, XRD, FE-SEM, EPMA, pXRF, WD-XRF and AAS. The geochemical results indicate substantially elevated Cu, As, Ni and Zn concentrations in the tailings. Mineralogical investigations revealed that the tailings contain valuable minerals such as gold, cobaltite, and W-bearing rutile. The last could be used as an indicator mineral in tailings classification and possibly also in future ore exploration. The study of secondary mineralogy revealed that the most weathered top layers of the tailings show secondary alteration rims on the surfaces of mineral particles, and the enrichment of As and Ni in the Fe- and Mn-oxide minerals.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48008767","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}
N. Nordbäck, Nikolas Ovaskainen, M. Markovaara‐Koivisto, P. Skyttä, A. Ojala, Jon Engström, C. Nixon
Fracture studies commonly lack data for the length range between 10 m to 1 km. For this reason, scaling laws are required to extrapolate fracture properties, for example in discrete fracture network models. This study focused on analysis and correlation of topology, orientation and length distribution of multiscale fracture datasets to assess their scalability. The used datasets comprise UAV-derived photogrammetric models from natural outcrops and lineaments mapped using airborne LiDAR, bathymetry and aerogeophysical data, in several contrasting scales and resolutions. This study highlights challenges in acquiring uncensored and coherent brittle structural datasets from source data characterized by a large span of resolutions between the remote sensing datasets and models of the fractured outcrop. In specific, collected data was found to be potentially biased and affected by uncertainties related to both the censoring by sedimentary cover and the scale of observation. Our results revealed differences between lineament and outcrop fracture orientations, as well as difficulties in assessing topological parameters from lineament datasets. The 1:200000 resolution was found best suited to the mapping of lineament length and resulted in a length distribution power law exponent of -1.92. For outcrop fractures that are less than 2 m long, the lognormal length distribution provided the only good fit to our data, while the longer outcrop fractures fitted relatively well with a power law exponent of -2.26.
{"title":"Multiscale mapping and scaling analysis of the censored brittle structural framework within the crystalline bedrock of southern Finland","authors":"N. Nordbäck, Nikolas Ovaskainen, M. Markovaara‐Koivisto, P. Skyttä, A. Ojala, Jon Engström, C. Nixon","doi":"10.17741/bgsf/95.1.001","DOIUrl":"https://doi.org/10.17741/bgsf/95.1.001","url":null,"abstract":"Fracture studies commonly lack data for the length range between 10 m to 1 km. For this reason, scaling laws are required to extrapolate fracture properties, for example in discrete fracture network models. This study focused on analysis and correlation of topology, orientation and length distribution of multiscale fracture datasets to assess their scalability. The used datasets comprise UAV-derived photogrammetric models from natural outcrops and lineaments mapped using airborne LiDAR, bathymetry and aerogeophysical data, in several contrasting scales and resolutions. This study highlights challenges in acquiring uncensored and coherent brittle structural datasets from source data characterized by a large span of resolutions between the remote sensing datasets and models of the fractured outcrop. In specific, collected data was found to be potentially biased and affected by uncertainties related to both the censoring by sedimentary cover and the scale of observation. Our results revealed differences between lineament and outcrop fracture orientations, as well as difficulties in assessing topological parameters from lineament datasets. The 1:200000 resolution was found best suited to the mapping of lineament length and resulted in a length distribution power law exponent of -1.92. For outcrop fractures that are less than 2 m long, the lognormal length distribution provided the only good fit to our data, while the longer outcrop fractures fitted relatively well with a power law exponent of -2.26.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44313356","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}
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