Deformation events in the Gridino zone, Belomorian Province, Fennoscandian Shield: relationships between mafic dike swarms and eclogite-bearing mélange

Babarina, I. I.; Sibelev, O. S.

doi:10.1080/00206814.2014.971079

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…The source for the Gridino mafic dykes could be enriched mantle (Figure ), with the dykes representing the response to a plume‐related thermal pulse at 2.80–2.70 Ga (Mints et al., ; Skublov, Astaf'ev et al., ; Skublov, Berezin et al, ). Subsequently, the dykes and host TTGs were deformed, with some dykes forming boudins within the foliation of the host gneiss (Babarina & Sibelev, ). A second thermal event occurred at c .…”

Section: Discussionmentioning

confidence: 99%

Age and P–T conditions of the Gridino‐type eclogite in the Belomorian Province, Russia

Zhang

Wei

et al. 2017

Journal Metamorphic Geology

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Although eclogites in the Belomorian Province have been regarded as Archean in age and among the oldest in the world, there are also multiple studies that have proposed a Paleoproterozoic age. Here, we present new data for the Gridino‐type eclogites, which occur as boudins and metamorphosed dykes within tonalite–trondhjemite–granodiorite gneisses. Zircon from these eclogites has core and rim structures. The cores display high Th/U ratios (0.18–0.45), negative Eu anomalies and strong enrichment in HREE, and have Neoarchean U–Pb ages of c. 2.70 Ga; they are interpreted to be magmatic in origin. Zircon cores have δ18O of 5.64–6.07‰ suggesting the possibility of crystallization from evolved mantle‐derived magmas. In contrast, the rims, which include the eclogite facies minerals omphacite and garnet, are characterized by low Th/U ratios (<0.035) and flat HREE patterns, and yield U–Pb ages of c. 1.90 Ga; they are interpreted to be metamorphic in origin. Zircon rims have elevated δ18O of 6.23–6.80‰, which was acquired during eclogite facies metamorphism. Based on petrography and phase equilibria modelling, we recognize a prograde epidote amphibolite facies mineral assemblage, the peak eclogite facies mineral assemblage and a retrograde high‐P amphibolite facies mineral assemblage. The peak metamorphic conditions of 695–755°C at >18 kbar for the Gridino‐type eclogites suggest an apparent thermal gradient of <39–42°C/kbar for the Lapland–Kola collisional orogeny.

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Section: Discussionmentioning

confidence: 99%

Age and P–T conditions of the Gridino‐type eclogite in the Belomorian Province, Russia

Zhang

Wei

et al. 2017

Journal Metamorphic Geology

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“…The Belomorian Province is built up by 2.9-2.6 Ga TTG gneisses, 2.9-2.7 Ga subordinate metavolcanics (including andesites, boninites), ultramafic rocks and metasediments and 2.9 Ga amphibolites with relics of eclogites [37,40], which compose nappes and tectonic sheets [17,29,35,37,40]. The Archean Belomorian and Paleoproterozoic Lapland-Kola oro-genies are characterized by several deformational events under conditions of high-and moderate-pressure amphibolite-to granulite-facies metamorphism, which was locally superimposed on eclogites [14,17,22,25,[27][28][29]35,37,41]. Eclogites that are assumed to be Archean in age occur as their almost completely retrogressed (symplectized) relics in Mesoarchean amphibolites hosted by TTG gneisses [15][16][17][27][28][29]37].…”

Section: Geological Settingmentioning

confidence: 99%

“…The Archean Belomorian and Paleoproterozoic Lapland-Kola oro-genies are characterized by several deformational events under conditions of high-and moderate-pressure amphibolite-to granulite-facies metamorphism, which was locally superimposed on eclogites [14,17,22,25,[27][28][29]35,37,41]. Eclogites that are assumed to be Archean in age occur as their almost completely retrogressed (symplectized) relics in Mesoarchean amphibolites hosted by TTG gneisses [15][16][17][27][28][29]37].…”

Section: Geological Settingmentioning

confidence: 99%

“…The orogenic core is located between the Archean Kola north-east-verging and Archean Belomorian south-west-verging provinces interpreted as north-eastern and south-western forelands of the LKO, respectively [42,43]; the LKO possesses, thus, a palm-like structure [45]. Paleoproterozoic eclogites comprise patches of eclogitization superimposed on both Archean eclogites and early Paleoproterozoic mafic dikes and intrusions and differ in lower extent of retrogression [22][23][24][25][26][27][28]37]. These are suggested to have resulted from the Lapland-Kola collisional orogeny, which led tp high-pressure conditions in the lowermost parts of the over-thickened crust in the Belomorian Province [28] or from subduction of the Lapland-Kola oceanic crust [46].…”

Section: Geological Settingmentioning

confidence: 99%

“…The presence of Early Precambrian eclogites in the Belomorian Province is an undoubted fact (Figure 1a). These rocks are divided into two age groups, Archean and Paleoproterozoic, based on field observations and petrological and geochronological data [14,[27][28][29]. Relics of the Archean eclogites have been recognized in boudins of amphibolites that along with their country tonalite-trondhjemite-granodiorite (TTG) gneisses build up the Archean Gridino eclogite-bearing mélange [15,30,31].…”

Section: Introductionmentioning

confidence: 99%

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Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding

et al. 2021

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Early Precambrian retrogressed eclogites are abundant in the central and northern parts of the Belomorian Province of the Fennoscandian Shield (Gridino + Keret and Salma + Kuru-Vaara study areas, respectively). Older and younger eclogites are recognized and their Archean and Paleoproterozoic ages are argued. Archean eclogites are intensely retrogressed and occur in amphibolite boudins in the tonalite-trondhjemite-granodiorite (TTG) gneiss matrix of the Archean Gridino eclogite-bearing mélange. Less retrogressed Paleoproterozoic eclogites form patches in mafic dikes and some amphibolite boudins; their Paleoproterozoic age is supported by U-Pb/SIMS data on zircons depleted in heavy rare earth elements (REE) with omphacite, garnet, and kyanite inclusions, and Sm-Nd and Lu-Hf mineral isochrons. Archean eclogites contain Archean heavy rare-earth elements (REE)-depleted zircons with garnet and zoisite inclusions and Archean garnets. No omphacite inclusions were found in these zircons, and this fact was considered as evidence against the existence of Archean eclogites. This study reports on the first finding of omphacite (23–25% Jd) inclusions in 2.68 Ga metamorphic zircons from eclogites from the Gridino eclogite-bearing mélange. The zircons are poorly enriched in heavy REE and display a weak negative Eu-anomaly but a poor positive Ce-anomaly typical of eclogitic zircons. Thus, zircons with these decisive features provide evidence for an Archean eclogite-facies metamorphism.

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Garnet Lu Hf geochronology and P-T path of the Gridino-type eclogite in the Belomorian Province, Russia

Zhang

Lanari

et al. 2019

Lithos

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Deformation events in the Gridino zone, Belomorian Province, Fennoscandian Shield: relationships between mafic dike swarms and eclogite-bearing mélange

Cited by 12 publications

References 14 publications

Age and P–T conditions of the Gridino‐type eclogite in the Belomorian Province, Russia

Age and P–T conditions of the Gridino‐type eclogite in the Belomorian Province, Russia

Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding

Garnet Lu Hf geochronology and P-T path of the Gridino-type eclogite in the Belomorian Province, Russia

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