3.4 Evolution of the Palaeoproterozoic (2.50–1.95 Ga) Non-orogenic Magmatism in the Eastern Part of the Fennoscandian Shield

Hanski, Eero

doi:10.1007/978-3-642-29682-6_6

Cited by 12 publications

(10 citation statements)

References 105 publications

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“…1.9-1.7 Ga [53]. In the Paleoproterozoic (2.50-1.95 Ga), the Karelian craton experienced a number of intraplate magmatic events [54], some of which were likely parts of large igneous provinces (LIPs) [40]. Paleoproterozoic volcanic and sedimentary volcanic successions were deposited and are now preserved in the Onega structure, Perapohja schist belt, Salla-Kuolajarvi basin, and so forth.…”

Section: Regional Geologymentioning

confidence: 99%

Metallogenic Setting and Evolution of the Pados-Tundra Cr-Bearing Ultramafic Complex, Kola Peninsula: Evidence from Sm–Nd and U–Pb Isotopes

et al. 2020

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The article presents new Sm–Nd and U–Pb geochronological data on rocks of the poorly studied Pados-Tundra Cr-bearing complex. It is part of the Notozero mafic–ultramafic complex (western Kola Peninsula) and occurs at the border of the Paleoproterozoic Lapland Granulite Belt and the Archean Belomorian composite terrain. The Pados-Tundra complex hosts two major zones, the Dunite and Orthopyroxenite Blocks. Dunites are associated with four levels of chromite mineralization. Isotope Sm–Nd studies of dunites, harzburgites, and orthopyroxenites from the central part of the complex have been carried out. The isochron Sm–Nd age on 11 whole-rock samples from a rhythmically layered series of the complex is 2485 ± 38 Ma; the mineral Sm–Nd isochron for harzburgites shows the age of 2475 ± 38 Ma. It corresponds with the time of large-scale rifting that originated in the Fennoscandian Shield. When the rhythmically layered series of the intrusion and its chromite mineralization were formed, hornblendite dykes intruded. The U–Pb and Sm–Nd research has estimated their age at ca. 2080 Ma, which is likely to correspond with the occurrence of the Lapland–Kola Ocean. According to isotope Sm–Nd dating on metamorphic minerals (rutile, amphibole), the age of postmetamorphic cooling of rocks in the complex to 650–600 °C is 1872 ± 76 Ma. The U–Pb age on rutile from a hornblendite dyke (1804 ± 10 Ma) indicates further cooling to 450–400 °C. The conducted research has determined the early Proterozoic age of rocks in the rhythmically layered series in the Pados-Tundra complex. It is close to the age of the Paleoproterozoic ore magmatic system in the Fennoscandian Shield that developed 2.53–2.40 Ga ago. Later episodes of alterations in rocks are directly related to main metamorphic episodes in the region at the turn of 1.9 Ga. Results of the current study expand the geography of the vast Paleoproterozoic East Scandinavian Large Igneous Province and can be applied for further studies of similar mafic–ultramafic complexes.

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Section: Regional Geologymentioning

confidence: 99%

Metallogenic Setting and Evolution of the Pados-Tundra Cr-Bearing Ultramafic Complex, Kola Peninsula: Evidence from Sm–Nd and U–Pb Isotopes

et al. 2020

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“…The record of these formations spans a geological evolution of around 600 Ma and has been traditionally subdivided by Finnish and Russian researchers into several major informal stratigraphic units. For detailed summaries of the sedimentological and magmatic evolution during this time period; see Hanski and Melezhik (2012) and Hanski (2012). The time periods of formation are the following: Sumian (2505-2430 Ma), Sariolian (2430-2300 Ma), Jatulian (2300-2060 Ma), Ludicovian (2060-1960Ma), and Kalevian (1960-1900.…”

Section: Geological Evolution Of the Bedrock Of Finlandmentioning

confidence: 99%

“…In Finland, the most prominent examples include the Tornio-Näränkävaara belt of intrusions ( Fig. Currently, it seems that there were two magmatic episodes, at around 2500 Ma and around 2435-2445 Ma, but more precise dating is needed (see Hanski, 2012, for a discussion on geochronology). This magmatism and associated continental extension is commonly attributed to the impact of a mantle plume head at the base of the craton (Amelin et al, 1995;Hanski et al, 2001b), though this model in its simplest form meets some difficulties if the prolonged magmatic history of more than 50 Ma is real.…”

Section: Geological Evolution Of the Bedrock Of Finlandmentioning

confidence: 99%

“…Though not located in Finland, it is worth mentioning that the most conspicuous rocks of this period (Shunga event) are the extremely carbon-rich rocks in Russian Karelia, called maksovites and shungites, which are interpreted to represent petrified oil-rich deposits (Melezhik et al, 2013b). Although it is not clear whether the Archean craton was already totally disrupted at this stage, most mafic magmas do not show isotopic signatures indicative of interaction with continental crust (Hanski, 2012), with the remarkable exceptions being some Ni-Cu sulfidebearing intrusions (e.g., Kevitsa; Hanski et al, 1997). These komatiites and picrites are found in central Finnish Lapland, differing clearly in the mode of occurrence and chemistry from the older Sariolian komatiites in the same region (Hanski et al, 2001a).…”

Section: Geological Evolution Of the Bedrock Of Finlandmentioning

confidence: 99%

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Synthesis of the Geological Evolution and Metallogeny of Finland

Hanski¹

2015

Mineral Deposits of Finland

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“…Далее к Ю и ЮЗ наиболее древние образования сумийского, сариолийского и ятулийского надгоризонтов палеопротерозоя, выходящие по периферии и в центральной части Северо-Онежского син-клинория, надстраиваются людиковийским, калевийским и вепсийским горизонтами отло-жений палеопротерозоя. Основное развитие ОС происходило в период 2,3-1,65 млрд л. н., охватывая практически весь палеопротерозой, и сопровождалось основным и ультраоснов-ным магматизмом [Светов, Свириденко, 2005;Онежская…, 2011;Рязанцев, Куликов, 2012;Hanski, 2013;Степанова и др., 2014;и др. ].…”

Section: Introductionunclassified

On Recent Faults and Paleoseismic Fractures in the Palaeoproterozoic Onega Structure of the Baltic Shield

Никонов¹,

Zykov²,

Nikonov³

et al. 2017

Proceedings of KarRC of RAS

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В пределах Онежской структуры Фенноскандинавского (Балтийского) щита Восточно-Европейской платформы обнаружены специфические морфоструктуры, отражающие импульсные сейсмотектонические события. Анализ литературных данных показал, что подобные морфоструктуры выделялись российскими учеными в этих местах уже с XIX века. Изучение их эволюции, кинематики и соотношение морфоструктур с палеопротерозойской геологической структурой региона выяви-ли ряд признаков аккомодации новейших тектонических движений к древней струк-туре. В частности, установлена приуроченность к ней поздне-и послеледниковых разрывов. Обосновывается отнесение большинства из выявленных морфоструктур к дислокациям, сформированным за счет мощных сейсмических воздействий на ряде участков. Подтверждается длительность эволюции палеопротерозойских ин-траконтинентальных морфоструктур и расширяется возможность уточнения оце-нок долговременной сейсмической опасности в области тектонической аккомода-ции Фенноскандинавского щита в пределах флексуры А. А. Полканова. К л ю ч е в ы е с л о в а: Восточно-Европейская платформа; Фенноскандинавский щит; Онежская структура; палеоземлетрясения; тектоническая аккомодация; не-отектоника; палеосейсмодислокации. A. A. Nikonov, A. V. Poleshchuk, D. S. Zykov. ON RECENT FAULTS AND PALEOSEISMIC FRACTURES IN THE PALAEOPROTEROZOIC ONEGA STRUCTURE OF THE FENNOSCANDIAN SHIELDSpecific morphological structures corresponding to impulsive seismotectonic events were identified within the Onega structure of the Fennoscandian (Baltic) shield of the East European platform. Analysis of data from the literature showed that similar morphological structures have been detected by Russian scientists in this area already since the 19 th century. The study of evolution, kinematics, and the correlation of the morphostructures with the region's Palaeoproterozoic geological structure suggest that recent tectonic movements have been accommodated to the ancient structure. In particular, late-and postglacial faults were found to be associated to this structure. We prove that a majority of the identified morphostructures are dislocations caused by strong seismic impacts in a number of areas. The prolonged evolution of the Palaeoproterozoic intracontinental morphostructures is confirmed, and the possibilities for refining the estimates of longterm seismic hazard in the area of tectonic accommodation of the Fennoscandian shield in the central sector of the Polkanov flexure are expanded.

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3.4 Evolution of the Palaeoproterozoic (2.50–1.95 Ga) Non-orogenic Magmatism in the Eastern Part of the Fennoscandian Shield

Cited by 12 publications

References 105 publications

Metallogenic Setting and Evolution of the Pados-Tundra Cr-Bearing Ultramafic Complex, Kola Peninsula: Evidence from Sm–Nd and U–Pb Isotopes

Metallogenic Setting and Evolution of the Pados-Tundra Cr-Bearing Ultramafic Complex, Kola Peninsula: Evidence from Sm–Nd and U–Pb Isotopes

Synthesis of the Geological Evolution and Metallogeny of Finland

On Recent Faults and Paleoseismic Fractures in the Palaeoproterozoic Onega Structure of the Baltic Shield

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