Russian Karelia Research Articles

Palaeoproterozoic magnesite-stromatolite-dolostone-'red bed' association, Russian Karelia: Palaeoenvironmental constraints on the 2.0 Ga-positive carbon isotope shift

The ca. 2000 Ma Tulomozerskaya Formation, Russian Karelia, is composed of an 800 m-thick magnesite-stromatolite-dolostone-'red bed' succession with the most 13 C-rich dolostones (up to +18‰ V-PDB) that have ever been reported. Terrigenous 'red beds' are developed throughout the sequence and represent three main depositional settings: (1) a braided fluvial system over a lower energy, river-dominated coastal plain, (2) a low-energy, barred lagoon or bight, and (3) a non-marine, playa lake. A significant component of the sequence consists of biostromal and biohermal columnar stromatolites accreted in shallow-water, low-energy, intertidal zones, barred evaporitic lagoons and peritidal evaporitic environments. Only a small portion of stromatolites might have been accreted in relatively 'open' marine environments. The red, flat-laminated, dolomitic and magnesite stromatolites formed in evaporative ephemeral ponds, coastal sabkhas and playa lakes. Tepees, mudcracks, pseudomorphs after calcium sulphate, halite ca...

Paragenesis and origin of staurolite from a palladium-rich gabbronorite: an unusual occurrence from the Lukkulaisvaara layered intrusion, Russian Karelia

Paragenesis and origin of staurolite from a palladium-rich gabbronorite: an unusual occurrence from the Lukkulaisvaara layered intrusion, Russian Karelia

Paleomagnetism of 2.44 Ga mafic dykes in Russian Karelia, eastern Fennoscandian Shield — implications for continental reconstructions

Results of a paleomagnetic study of Paleoproterozoic dykes and Archean host rocks in the eastern Fennoscandian shield are reported here. Most of the dykes are related to ca 2440 Ma layered intrusions and have isotopic ages between 2349 and 2476 Ma. The dykes form an extensive NW–SE and E–W trending swarm. The majority are unaltered gabbronorites which carry stable remanent magnetizations with multicomponent nature. The high temperature remanence component (D), which is thought to represent the primary 2.44 Ga magnetization of the dykes, has a paleomagnetic pole at 20°S, 278.8°E (A95=6.0°, N=11 sites). Another D-like component (D′) with shallower inclination (VGP 9.6°N, 256.2°E, eight samples), at one site from baked Archean host rock may also represent the primary remanence of the dykes. The commonest remanence component (A) records an extensive Svecofennian partial overprint and is interpreted to be ca 1.84 Ga old. It yields a paleomagnetic pole at 52.6°N, 226.8°E (A95=2.7°, N=23). The fourth component, B, has a paleopole at 53.9°N, 169.6°E (A95=6.3°, N=16) and is inferred to be ca 1.75 Ga on the basis of isotopic dating, although ages of 2.1, 1.3 and 0.3 Ga are also possible. Baked contact tests for the 2.44 Ga dykes are negative, as shown by the occurrence of component D in Archean host rocks beyond one dyke width. It is proposed that the negative baked contact test indicates regional reheating and remagnetization of the Archean basement at ca 2.44 Ga ago due to the spatially vast occurrence of coeval 2.44 Ga mafic dykes, layered intrusions, volcanics and granites in the area. Based on this hypothesis, it is suggested that component D in the dykes may be primary and acquired at ca 2.44 Ga ago. The similarity of pole D with poles from coeval dykes and layered intrusions elsewhere in the Karelian Province and Kola Peninsula suggest that, within the Archean domain of the Fennoscandian shield, no large scale block movements have taken place since 2.44 Ga. At 2.44 Ga the Fennoscandian Shield was located at the latitude of ca 30°S which is different to that at 1.84 and 1.75 Ga, when Fennoscandia was located at the latitudes of ca 30°N. A continental reconstruction based on pole D and the pole from the 2.45 Ga Matachewan dykes of the Superior craton in Laurentia, places the Kola Peninsula adjacent to southern Greenland. Reconstructions based on recent geological interpretations and a reconstruction yielding pole D′, are also discussed.

The <i>Polistes</i> species in northern Europe (Hymenoptera: Vespidae)¹

Records of Polistes nimpha (Christ, 1791) (P. opinabilis Kohl, 1898) from Finland, Russian Karelia, the Baltic countries and some adjacent areas, those of P. biglumis (L. 1758) from Scandinavia and those of P. dominulus (Christ, 1791) (P. gallicus auct.) from the Baltic countries are mapped. The distribution of P. biglumis is boreomontane; in Scandinavia the range is disjunct and recent nesting records in the province of Norrbotten in Sweden (about 66°N) are the northernmost of all Polistes species in the world. The northern habitats of P. biglumis in Sweden are open areas of stony ground about 150 m above sea level. The stones store insolating warmth and the microclimatic conditions are suitable for development of the brood on open combs. P. dominulus is expanding its range northwards in Europe. Nomenclature, colour variation and diagnostic characters of the three Polistes species are treated.

Extreme [formula omitted] enrichment in ca. 2.0 Ga magnesite–stromatolite–dolomite–`red beds' association in a global context: a case for the world-wide signal enhanced by a local environment

The Palaeoproterozoic positive excursion of δ 13 C carb is now considered as three positive shifts of δ 13 C carb separated by returns to 0‰, which all occurred between 2.40 and 2.06 Ma. This isotopic event is unique in terms of both duration (>300 Ma) and 13 C enrichment (up to +18‰). The mechanism responsible for one of the most significant carbon isotopic shifts in Earth history remains highly debatable. To date, δ 13 C of +10‰ to +15‰ cannot be balanced by organic carbon burial ( f org) as there is no geological evidence for an enhanced C org accumulation prior to or synchronous with the excursion. Instead, termination of these excursions is followed by formation of a vast reservoir of 13 C -depleted organic material (−45‰ at Shunga) and by one of the earliest known oil-generation episodes at 2.0 Ga. None of the three positive excursions of δ 13 C carb is followed by a negative isotopic shift significantly below 0‰, as has always been observed in younger isotopic events, reflecting an overturn of a major marine carbon reservoirs. This may indicate that f org was constant: implying that the mechanism involved in the production of C org was different. Onset of intensive methane cycling resulting in Δ c change is another possibility. The majority of sampled 13 C carb -rich localities represents shallow-water stromatolitic dolostones, `red beds' and evaporites formed in restricted intracratonic basins, and may not reflect global δ 13 C carb values. Closely spaced drill core samples ( n=73) of stromatolitic dolostones from the >1980±27 Ma Tulomozerskaya Formation in the Onega palaeobasin, Russian Karelia, have been analysed for δ 13 C carb and δ 18 O carb in order to demonstrate that different processes were involved in the formation of 13 C carb -rich carbonates. The 800 m-thick magnesite–stromatolite–dolomite–`red beds' succession formed in a complex combination of environments on the Karelian craton: peritidal shallow marine, low-energy protected bights, barred basins, evaporative ephemeral ponds, coastal sabkhas and playa lakes. The carbonate rocks exhibit extreme 13 C enrichment with δ 13 C values ranging from +5.7 to +17.2‰ vs. V-PDB (mean+9.9±2.3‰) and δ 18 O from 18.6 to 26.0‰ vs. V-SMOW (mean 22.0±1.6‰). The Tulomozerskaya isotopic excursion is characteristic of the global 2.4–2.06 Ga positive shifts of carbonate 13 C/ 12 C , although it reveals the greatest enrichment in 13 C known from this interval. An external basin(s) is considered to have provided an enhanced C org burial and global seawater enrichment in 13 C : the global background value for the isotopic shift at Tulomozero time (ca. 2.0 Ga) is roughly estimated at around +5‰. An explosion of stromatolite-forming microbial communities in shallow-water basins, evaporative and partly restricted environments, high bioproductivity, enhanced uptake of 12 C , and pene-contemporaneous recycling of organic material in cyanobacterial mats with the production and consequent loss of CO 2 (and CH 4?) are believed to be additional local factors which may have enhanced δ 13 C from +5‰ up to +17‰. Such factors should be taken into account when interpreting carbon isotopic data and attempting to discriminate between the local enrichment in 13 C and globally enhanced δ 13 C values. We propose that many previously reported δ 13 C values from other localities, where environmental interpretations are not available or have not been taken into account may not represent the global δ 13 C values.

1.8 Ga Svecofennian post-collisional shoshonitic magmatism in the Fennoscandian shield

At least 14 small (1–11 km across) 1.8 Ga Svecofennian post-collisional bimodal intrusions occur in southern Finland and Russian Karelia in a 600-km-long belt from the Åland Islands to the NW Lake Ladoga region. The rocks range from ultramafic, calc-alkaline, apatite-rich potassium lamprophyres to peraluminous HiBaSr granites, and form a shoshonitic series with K 2O+Na 2O>5%, K 2O/Na 2O>0.5, Al 2O 3>9% over a wide spectrum of SiO 2 (32–78%). Although strongly enriched in all rocks, the LILE Ba and Sr and the LREE generally define a decreasing trend with increasing SiO 2. Depletion is noted for HFSE Ti, Nb and Ta. Available isotopic data show overlapping values for lamprophyres and granites within separate intrusions and a cogenetic origin is thus not precluded. Initial magmas (Mg#>65) in this shoshonitic association are considered to be generated in an enriched lithospheric mantle during post-collisional uplift some 30 Ma after the regional Svecofennian metamorphic peak. However, prior to the melting episode, the lithospheric mantle was affected by carbonatite metasomatism; more extensively in the east than in the west. The melts generated in the more carbonate-rich mantle are extremely enriched in P 2O 5∼4%, F∼12,000 ppm, LILE: Ba∼9000 ppm, Sr∼7000 ppm, LREE: La∼600 ppm and Ce∼1000 ppm. The parental magma underwent 55–60% fractionation of biotite+clinopyroxene+apatite+magnetite+sphene whereupon intermediate varieties were produced. After further fractionation, 60–80%, of K-feldspar+amphibole+plagioclase±(minor magnetite, sphene and apatite), leucosyenites and quartz-monzonites were formed. In the west, where the source was less affected by carbonatite metasomatism, calc-alkaline lamprophyres (vogesites, minettes and spessartites) and equivalent plutonic rocks (monzonites) were formed. Removal of about 50% of biotite, amphibole, plagioclase, magnetite, apatite and sphene produced peraluminous HiBaSr granites. The impact of crustal assimilation is considered to be low. At about 1.8 Ga, the post-collisional shoshonitic magmatism brought juvenile material, particularly enriched in alkalis, LILE, LREE and F, into the crust. Although areally restricted, the regional distribution of the post-collisional intrusions may indicate that larger volumes of 1.8 Ga juvenile material resides in unexposed parts of the crust.

Ecological simulation model for studying diversity of stand structure in boreal forests

A gap model was developed for studying stand structure from the standpoint of biological diversity. In this model, stand structure is described by the diameter distribution of living and dead trees. The stage of decay and position of dead trees are also shown. The model output was compared with results from the literature representing sites in northern Europe, i.e. Finland, Sweden and Russian Karelia. The growth and structure of the pure pine stand were similar to those of measured stands, and the growth of spruce and birch stands were quite similar to that of the measured stands; but growth of alder and aspen stands deviated from that of measured stands. The growth and structure of a mixed stand were quite similar to the growth and structure of measured stands. Pure and mixed stands responded to management as would be expected based on the model. The model, which elaborately outlines how different forest management practices affect stand structure, can be used as a tool for research and decision making.

Atlantic salmon (Salmo salav L.) catches in Russia

Summary Atlantic salmon are caught in the coastal waters of the Baltic, Barents and White seas, in their river basins and in the lakes of Russia. About 1.5–2.0 × 103 tonnes of salmon were caught annually in these regions during the late 19th and early 20th centuries. Overfishing, dam construction and pollution of biotopes have resulted in habitat loss in the Gulf of Finland coastal waters and in the rivers and lakes of Russian Karelia. In the Arkhangelsk region, salmon yield has decreased by a factor of 3.5 when compared to data from the 1930–40s. The salmon harvest from the Kola Peninsula appears to have remained the most steady while, for the past decade, the Pechora and Varzuga rivers have yielded more than 50–60 % of the total Russian salmon catch. This crisis in restocking shows an urgent need for the rapid development of a federal programme to conserve the Atlantic salmon genetic resources within the region.

Estimating sapling vitality for Scots pine ( Pinus sylvestris L.) in Russian Karelia

A new method is proposed for estimating vitality or growth potential for saplings of Scots pine ( Pinus sylvestris L.), based on height, diameter and height increment. A two-stage process was used to establish the vitality index. The logarithms of height, diameter and height increment were regressed against age, to adjust for the wide range of ages present in our data (c. 10,000 saplings with ages spanning 4–50 years). Then principal component analysis was used to obtain coefficients, which were, in turn, standardized on each axis to provide a vitality index scaled in standard deviations. This standardized scale allows the rank of an individual in the population to be assessed, and draws attention to possible outliers. The use of age-adjusted residuals ensured that the estimator was independent of age, and stable over a wide age range. The first principal component indicates if a sapling is relatively tall (weight = 0.5), thick (w = 0.5) or fast-growing (w = 0.7) for its age. Most of the information is contained in the first principal component, but the second component, which explains about 10% of the variance, appears to offer some utility as an indicator of ‘acceleration’ due to changing conditions. The resulting measures of vitality have been useful for research and management in the dry lichen-moss pine forest in Russian Karelia, but are specific to this species, locality and ecotype. Further research and site-specific data are necessary to adapt the system to other situations.

Catches of <i>Ips duplicatus</i> and other non-target Coleoptera by <i>Ips typographus</i> pheromone trapping

Catches of non-target Coleoptera in Ips typographus pheromone traps baited with Ipslure® were analysed along a geographic gradient running from southwestem Finland to eastern Finland and Russian Karelia. Besides I. typographus, two other bark beetles, Pityogenes chalcographus and Ips duplicatus were caught in high numbers. I. duplicatus occuned on northeastern sites only, suggesting a more restricted distribution than previously known. High numbers of Thanasimus spp. beetles indicate that I. typographus pheromone is also an effective attractant for bark beetle predators. In addition, the originally North American ambrosia beetle Gnathotrichus materiarius, now widely spread in Europe was found for the first time in nature in Finland.

The structure of forest stands in virgin and managed peatlands: a comparison between Finnish and Russian Karelia

This study investigated the changes caused by management, including drainage and thinnings, in peatland forest stand structure. Drained peatland sites in Finnish North Karelia were compared within the same type groups and nutrient status levels of virgin peatlands in the Republic of Karelia, the Russian Federation. The variables studied, which depict stand structure variation, included: (1) the diameter of the median tree; (2) the range of sampled diameters; (3) the basal area of the stand; (4) the estimated number of tree storeys; and (5) the number of the tree species. The number of tree storeys was determined through non-parametric Kernel estimation. Over a long duration, management smooths the natural multi-modal structure of virgin peatland stocking by decreasing the variation in size-distribution. Management also changes the natural tree species dynamics on peatland sites by providing a competitive advantage to the tree species, which adjust best to the changed growing conditions. These species begin to dominate the habitat and reduce the species diversity. The effect of recent thinnings and cleaning cuttings on the forest structure is dependent upon fertility of the site and the stage of the forest stock at the moment of silvicultural operation. Cleaning cuttings may have also an increasing effect on the structural diversity of peatland forest stand.

Intensity of forest management and bark beetles in non‐epidemic conditions: a comparison between Finnish and Russian Karelia

Abstract: The population levels of bark beetles in non‐epidemic conditions were compared between intensively managed forests in Finnish Karelia and extensively managed forests in Russian Karelia. Thirty randomly chosen sample plots with five window flight traps in each were established in both countries. The numbers of species and individuals of bark beetles did not differ between the countries. This indicates that extensive forest management has not increased the general level of bark beetle populations. Species assemblages were, however, different between the countries and between the forest site types. Hylastes brunneus and Pityogenes bidentatus, which are common in stumps or in logging residue of Scots pine, were more abundant in Finland. Crypturgus subcribrosus, Polygraphus punctifrons, and Hylurgops glabratus, which prefer dead spruce trees in shady conditions, and Trypodendron signatum, which live in dead deciduous trees, were more common in Russia. Bark beetles were most abundant in old mesic forests. The amount of decaying wood on the ground did not correlate with the numbers of bark beetles caught.

The myxomycetes of boreal woodlands in Russian northern Karelia : a preliminary report

The myxomycetes of boreal woodlands in Russian northern Karelia : a preliminary report

Genetic variation in Arabis petraea, a disjunct species in northern Europe

Variation at 7 isoenzyme loci was studied m 15 populations (6 from Iceland, 4 from W Norway, 4 from central Sweden at the Bothnian Gulf, and 1 from Russian Karelia) Heterozygosity within populations was found to be remarkably high compared with taxa with similar reproductive systems and phytogeographical histories Genetic distances calculated from isoenzyme data showed a close connection between the Norwegian and Swedish populations, indicating a western rather than an eastern immigration route for the isolated Swedish population Leaf shape variation displayed a large scale geographical pattern with strong differences between regions and low variation within populations

Palaeomagnetism of Precambrian basic intrusion and dykes of Northern Karelia, eastern Fennoscandian Shield

Palaeomagnetic results for mafic and ultramafic intrusions and their country rocks in Russian Karelia are presented. The oldest rock type is pyroxene-hornblende gabbro, regarded as late Archaean or Palaeoproterozoic in age. Later, at the early stage of formation of a volcanic-plutonic association, including layered intrusions and metavolcanites, gabbro-norite dykes were emplaced. Sm-Nd isotopic analyses of this association yield mineral and whole-rock ages of 2.47-2.35 Ga with ∈ Nd = −0.4 to 1.2 for gabbro-norite dykes. Based on field relations, the youngest rock types are pyroxene-plagioclase porphyry dykes and gabbro-dolerite dykes. Three distinct magnetization components were isolated by alternating field and thermal demagnetization. The most common remanence component B, with a mean direction of D = 30°, I = 58°, k = 52, α 95 = 10° ( N = 5 geological units), is an overprint interpreted to have been acquired at the last stage of the Svecofennian orogeny (1.90-1.70 Ga). Component A, with a mean direction of D = 350°, I = 49°, k = 69, α 95 = 9° ( N = 5 geological units), is also an overprint, probably acquired at the onset of the Svecofennian orogeny. Both components are found in all rocks studied. Component C, with a mean direction of D = 126°, I = 73°, k = 167, α 95 = 10° ( N = 3 geological units), is isolated as a primary remanence in the pyroxene-hornblende gabbro intrusion and gabbro-norite dykes. The results are compared with other contemporaneous palaeomagnetic poles from Finland and Russian Karelia.

Nature, particularly the insect fauna of Ladoga and Olonets Karelia

The geology, vegetation, entomological studies, postglacial immigration of insects and characteristics of the insect fauna in southern Russian Karelia are reviewed, with examples of eastern and southern plant and insect species recorded in Russian Karelia, but not recorded or recorded to very limited extent in southern Finland. The management of forests and agriculture in Russian Karelia have been, during the Soviet period much less effective, and thus habitats have retained more diversity than in southern Finland. Recent studies indicate that many species considered threatened in Finland occur abundantly in Russian Karelia.

Petrology and Ni-Cu-Cr-PGE Mineralization of the Largest Mafic Pluton in Europe: The Early Proterozoic Burakovsky Layered Intrusion, Karelia, Russia

The largest mafic pluton in Europe (area = 630 km2, thickness = 5 to 7 km) is the early Proterozoic (2445 ± 4 Ma; Pb-Pb) Burakovsky Layered Intrusion (BLI). It is located in the southern part of Russian Karelia, in the SE part of the Baltic Shield, within an Archean granite-greenstone terrain. The BLI is overlain by Quaternary deposits, and our present understanding of its character, composition, and internal structure is based on geophysical surveys and the nature of the rocks at depth, as sampled by diamond drill core. In order to better understand the petrogenesis of the BLI, we present geologic, petrographic, mineral-chemical, and whole-rock chemical analyses from throughout the stratigraphic sequence. The BLI is a lopolith-like body and is divided into two major units: the Layered Series (LS), which exhibits layering that is discordant to the contact, and the Border Group (BG), with layering that conforms to the contact surface. The LS constitutes most of the BLI and consists of, from bottom to top: ...

The effects of the emissions of the Kostomuksha mining complex on the chemical composition of deposition and soil water in the surrounding pine forests

The Kostomuksha mining complex in Russian Karelia is a major emission point source surrounded by large forest areas near the Finnish border. The sulphur dioxide emissions of the complex are almost 60 000 tonnes and dust emissions about 5 000 tonnes a year. Research into the effects of emissions on the surrounding forests were started in a Finnish-Russian co-operation project in 1992. Deposition measurements during the two first years indicate that the effects of the emissions extend about 30 km to the west of the complex. The annual sulphur deposition near the mining complex has been about 300 mg/m2 in bulk precipitation and about 500 mg/m2 in throughfall. Sulphur emissions sometimes extend the eastern parts of Finland, but there the deposition is clearly smaller than near to the mining complex. The high calcium emissions neutralize the acidifying effect of sulphur near to the mine and smelter. The iron concentration in precipitation also increased near the complex. Sulphur and calcium decreased in percolation water on moving westwards.

Health promotion challenges for countries of the former Soviet Union: results from collaboration between Estonia, Russian Karelia and Finland

Health promotion challenges for countries of the former Soviet Union: results from collaboration between Estonia, Russian Karelia and Finland

Cryptic variation of augite in the Penikat Layered Intrusion, Northern Finland, with reference to megacyclic units and PGE-enriched zones

The Penikat Layered Intrusion is located in northern Finland, about 70 km to the south of the Arctic Circle. It belongs to a discontinuous layered intrusion belt about 300 km in length and about 2440 m.y. old which stretches from the Swedish-Finnish border to Russian Karelia. The Penikat Intrusion itself is 23 km long and 1.5 to 3.5 km wide. Its magmatic stratigraphy may be divided into a thin marginal series and a 2 to 3 km thick layered series. The latter is made up to five megacyclic units (MCU) which are attributed to repeated influxes of new magma into the Penikat chamber during solidification. The intrusion hosts at least seven PGE-enriched zones, the most remarkable of which are the SJ, AP and PV PGE Reefs. The SJ Reef is located at the boundary between MCU's III and IV, about 600 m above the base of the intrusion; the AP Reef in the lower part of MCU IV, about 300 m above the SJ Reef; and the PV Reef in the transition zone between MCU's IV and V, about 800 m above the AP Reef. The Penikat Intrusion underwent complex deformation and metamorphism during the Svecokarelian Orogeny, resulting in variable alteration of most of the magmatic minerals. Augite is the least altered magmatic mineral and was, therefore, selected to indicate changing composition during fractionation and the manner in which its composition reflects the existence of megacyclic units. Augite occurs as an intercumulus mineral in the ultramafic lower part and as a cumulus mineral in the gabbronoritic and anorthositic upper part of each megacyclic unit. The 100 Mg/(Mg + Fe2 + Mn) ratio shows decreasing trends in the three lower-most megacyclic units, excluding the lower part of MCU II, where a considerable reversal occurs, i.e. this ratio indicates progressive increase upward in the stratigraphy, providing evidence of magma mixing. The ratio decreases abruptly at the base of MCU and remains relatively constant in MCU's IV and V. The variation in the Cr2O3 content resembles that of the 100 Mg/(Mg + Fe2+ + Mn), and clearly indicates differences between the three lowermost chromium-rich and the two uppermost chromium-poor megacyclic units. The variations in TiO2 and MnO content form roughly mirror images with chromium, being lower in the lower part and higher in the upper part of the intrusion. Na2O correlates positively with chromium, since Na− provides a charge balance to Cr3+ in augite. Besides the megacyclic units, the Penikat Intrusion is characterized by an unusually great number of PGE-enriched zones, even though the total thickness of the intrusion is only about three kilometers unlike the Bushveld and Stillwater Complexes which are much thicker. It is suggested that the presence of these kinds of PGE zones in layered intrusions, which comprise similar megacyclic units, is linked to the multistage processes which are also related to the development of these units and take place within them. Thus the identification of these kinds of megacyclic units may serve as a useful tool in prospecting for PGE ores both here and in other layered intrusions. This investigation reveals that the well-known method of studying cryptic variation in ferromagnesian silicates, such as augite, clearly indicates the existence of megacyclic units even in fairly altered layered intrusions like the Penikat.