Geological evolution of the karelian granite-greenstone terrain

Лобач-Жученко, С. Б.; Levchenkov, O. A.; Chekulaev, V. P.; Krylov, I.N.

doi:10.1016/0301-9268(86)90014-8

Cited by 22 publications

(7 citation statements)

References 10 publications

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“…И ЕГО ОБРАМЛЕНИЯ Онежский синклинорий расположен в юго-восточной части КМ в пределах Водлозерского блока (домена) (рис. 4), который представляет собой наиболее древнее раннеархейское гранитогнейсовое ядро КМ [Kozhevnikov, 2000;Kozhevnikov et al, 2006Kulikov et al, 1990Kulikov et al, , 2017а, 2017bLevchenkov et al, 1989;, 2009Puchtel et al, 1991;Sergeev et al, 2007;Chekulaev et al, 2009а, 2009b. Границы Водлозерского домена условны и определены по расположению краевых мезоархейских (лопийских) зеленокаменных поясов.…”

Section: тектоника онежского синклинорияunclassified

On the Time and Conditions of Formation of the Shoksha Quartzite-Sandstones of the South Onega Depression Based on the New Data From Isotope Geochronology

Кузнецов

Kolodyazhnyi

Romanyuk

et al. 2023

Geodin. tektonofiz.

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The first results of U-Pb isotope dating of detrital zircons (dZr) from red-colored quartzitic-sandstones of the Shoksha formation (Shoksha horizon) are presented. The Shoksha formation completes the Vepsian sub-horizon (Vepsian) of the Lower Proterozoic of Karelia and is distributed within the South Onega trough. A sample (KL-555) of red-colored quartzitic sandstones was taken from the lower part of the section of the Shoksha formation in the same name deposit within the southwestern Cis-Onega Lake region. The 79 dZr grains isolated from this sample were analyzed by the staff of the Chemistry-Isotopic Analytic Laboratory of the GIN RAS using the equipment of the Shared Research Facilities of the GIN RAS. The weighted average of the three youngest U-Pb isotope dates for dZr grains is 1906±13 Ma. Taking into account the known isotopic dates of gabbro-dolerites from the Ropruchei sill, that cuts through the Shoksha formation, it makes possible to constrain the time of the Shoksha formation accumulation by ~1.90–1.75 Ga. A significant part of the carried out analyzes has yielded a high degree of discordance of the dates. The features of the distribution of the figurative points of these analyzes in the diagram with concordia suggest that the rocks of the studied section of the Shoksha formation were subjected to the alteration that disturbed the U-Pb isotope system of these zircon grains in the Phanerozoic.The set of obtained dates for dZr grains has been compared with the known ages of the crystalline complexes of the basement of the East European Platform. The age sets of dZr grains from sample KL-555 and rocks of the Ladoga group, developed along the margin of the Svecofennian accretionary orogen, are very similar (p similarity coefficient in Kolmogorov – Smirnov test is 0.27) and characterize mainly tectonic–magmatic events that had immediately preceded the manifestation of the Svecofennian orogeny (1.9–1.87 Ga). Therefore, the rocks of the Ladoga group could highly probably be a secondary source for the Shoksha quartzites. Based on a comparative analysis of ages and thorium-uranium ratios (Th/U) in dZr grains from sample KL-555, it was concluded that some of the studied dZr grains with high Th/U>1.5 originate from Ludicovian mafic rocks, but those with low Th/U<0.1 originate from ultra-high-pressure formations, such as eclogites known in the Salma, Kuru-Vaara and Gridino.A paleo-geographic scheme for the Late Vepsian is proposed, showing that the highly mature Shoksha sandstones were generated under continental conditions in a local basin due to the accumulation of clastic material carried by an extensive and branched

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Section: тектоника онежского синклинорияunclassified

On the Time and Conditions of Formation of the Shoksha Quartzite-Sandstones of the South Onega Depression Based on the New Data From Isotope Geochronology

Кузнецов

Kolodyazhnyi

Romanyuk

et al. 2023

Geodin. tektonofiz.

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“…The Suavjärvi structure is situated within the Karelian craton, which is the oldest (Neoarchean) stable domain of the Fennoscandian Shield (Lobach‐Zhuchenko et al. 1986; Rundquist and Mitrophanov 1993; Mints et al.…”

Section: Regional Geologymentioning

confidence: 99%

“…The Suavja¨rvi structure is situated within the Karelian craton, which is the oldest (Neoarchean) stable domain of the Fennoscandian Shield (Lobach-Zhuchenko et al 1986;Rundquist and Mitrophanov 1993;Mints et al 2009; and references therein). The basement of the craton is a late Archean (Lopian) granite-greenstone terrane consisting of granitoid-gneiss complexes and supracrustal rocks ranging in age between 3.14 and 2.62 Ga. Supracrustal metavolcanicsedimentary rocks form north-trending greenstone belts, surrounded by spatially more extensive granitoids and higher grade gneiss domains (Fig.…”

Section: Regional Geologymentioning

confidence: 99%

The Suavjärvi impact structure, NW Russia

Mashchak

Naumov

2012

Meteorit & Planetary Scien

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Abstract-We present the geology and interpreted shock features of the Suavja¨rvi circular structure. Suavja¨rvi is a circular feature (illustrated by satellite imagery, topography, and magnetic data) located in the central part of the Karelian Craton (lat. 63°07¢N, long. 33°23¢E). To date, little information on the geologic and impact features of the Suavja¨rvi structure is available in the literature. The structure is characterized by gravity and magnetic lows and disruption of the regional magnetic fabric. In the northeastern and southwestern parts of the structure, several erosional remnants of highly disturbed rocks occur referred to as monomict and polymict megabreccia. These comprise blocks of both basement granitoids and supracrustal greenstone rocks. The impact origin of polymict megabreccia and therefore of the Suavja¨rvi structure is confirmed by observations of closely spaced planar microstructures at angles consistent with planes that have Miller indices indicative of impact shock effects, mostly of x{10 13}. The Suavja¨rvi is considered to be a remnant of a deeply eroded and metamorphosed impact structure, which has a diameter of 16 km and was formed during the Paleoproterozoic (older than 2.2 Ga); this is inferred from the age of the overlying volcanic-sedimentary Jatulian sequence. Suavja¨rvi underwent regional metamorphism that resulted in obliteration or transformation of shock metamorphic effects. Massive sulfides occur within megabreccia; originating probably from postimpact redeposition of pre-existing mineralization.

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“…The calc-alkaline geochemical cahracter of this magmatism has been proposed by many authors (Lobach-Zhuckenko et al 1976;Gaål et al 1978;Vidal et al 1980;Auvray et al 1982;Martin and Quérré 1984). Fig.…”

Section: Constraintsmentioning

confidence: 99%

Origin and geodynamic evolution of the Archean crust of eastern Finland

Martin¹,

Auvray²,

Blais³

et al. 1984

Bull Geol Soc Finland

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The Archaean crust of eastern Finland is composed of three main lithological units: -Gneissic basement. It was originally composed of tonalites, trondhjemites and granodiorites emplaced at 2.86 G.a. and 2.62 G.a. and subsequently transformed into grey gneisses. The parental magmas originated from the mantle in a two-stage process: (i) formation of a basaltic crust, (ii) melting of this crust transformed into garnet-bearing amphibolite. Field, petrological and geochemical data argue in favour of a subduction-like process rather than an underplate accretion model. -Greenstone belt (Kuhmo-Suomussalmi). The lower volcanic sequence of this greenstone belt is composed of mafic and ultramafic lavas with komatiitic and tholeiitic affinities and was emplaced at about 2.65 G.a. The uprising of a mantle diapir initiated the breaking of the preexisting sialic crust (grey gneisses) and induced the emplacement of the greenstones in a proto-oceanic rift geodynamic environment. -Calc-alkaline magmatism. The calc-alkaline magmas were emplaced as volcanic rocks in the greenstone belt 2.5 G.a. ago (Luoma acid volcanics), or as K-feldspar phenocryst granodiorites in the immediate vicinity of the KuhmoSuomussalmi greenstone belt 2.5 G.a. ago (Suomussalmi and Arola augen gneisses). The younger plutons were emplaced as pink leucogranites 2.41 G.a. ago. The origin of this magmatism is thought to be correlated to the late tectonic evolution of the Kuhmo-Suomussalmi greenstone belt. The high density (d ~ 3.3) lavas of the lower volcanic sequence were emplaced over a low density (d -2.7) sialic crust. This created an inverse density gradient and generated a gravity instability that initiated the subsidence (sagduction) of the greenstone belt with respect to its basement. This later was carried down in the vicinity of the belt and underwent partial melting, thus generating the calc-alkaline magmas.It must be pointed out that, in the course of time, petrogenetic processes have changed from ensimatic to ensialic, implying a major reworking of the preexisting crustal materials.

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Geological evolution of the karelian granite-greenstone terrain

Cited by 22 publications

References 10 publications

On the Time and Conditions of Formation of the Shoksha Quartzite-Sandstones of the South Onega Depression Based on the New Data From Isotope Geochronology

On the Time and Conditions of Formation of the Shoksha Quartzite-Sandstones of the South Onega Depression Based on the New Data From Isotope Geochronology

The Suavjärvi impact structure, NW Russia

Origin and geodynamic evolution of the Archean crust of eastern Finland

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