Isotopic data (UPb, RbSr, PbPb and SmNd) on mafic granulites from finnish lapland

Bernard-Griffiths, J.; Peucat, Jean-Jacques; Postaire, B.; Vidal, Ph.; Convert, J.; Moreau, B.

doi:10.1016/0301-9268(84)90049-4

Cited by 84 publications

(19 citation statements)

References 17 publications

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“…Thick and cyclic sequence of khondalites may correspond to the Middle Lapponian metasediments, whereas the graphitic and calc-silicatic metasediments, felsic metavolcanic rocks and pyroxene peridotitic komatiites suggest an Upper Lapponian affinity. Further, Bernhard-Griffiths et al (1984) establish a Svecofennian age from a metavolcanic in the mafic charnockite suite. The Karelian rocks, i.e.…”

Section: Regional Geological Settingmentioning

confidence: 72%

“…As a chronostratigraphic enigma, the granulite complex is regarded as Archaean (2.8-2.5 Ga) by Meriläinen (1976) or as Karelian (2.4-2.0 Ga) by Barbey et al (1984). Bernhard-Griffiths et al (1984) have not recorded crustal events earlier than 2.0-1.9 Ga ago but do not deny the possible existence of older events in the granulite complex. Ages of 2.0-1.9 Ga are found in the mafic charnockites of plutonic origin (Meriläinen 1976, Bernhard-Griffiths et al 1984 1976) and hence show the minimum age of the sequence.…”

Section: Chronostratigraphic Evaluationmentioning

confidence: 92%

“…Bernhard-Griffiths et al (1984) have not recorded crustal events earlier than 2.0-1.9 Ga ago but do not deny the possible existence of older events in the granulite complex. Ages of 2.0-1.9 Ga are found in the mafic charnockites of plutonic origin (Meriläinen 1976, Bernhard-Griffiths et al 1984 1976) and hence show the minimum age of the sequence. The associated tectono-metamorphic convulsion is geochronologically verifiable in the khondalitic metasediments (Bernhard-Griffiths et al 1984).…”

Section: Chronostratigraphic Evaluationmentioning

confidence: 92%

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The Lapland greenstone belt: Stratigraphic and depositional features in northern Finland

Saverikko¹

1987

Bull Geol Soc Finland

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The Lapland greenstone belt formed in a continental environment, as a result of rifting of the 3.1-3.0 Ga Saamian craton. The basin subsided to a depth of five kilometres between 3.0-2.5 Ga and contains a sequence which is subdivided into Lower, Middle and Upper Lapponian groups, with the Middle Lapponian metasediments separating the Lower Lapponian Salla-Jauratsi and Upper Lapponian Kittilä greenstone successions. After a folding episode the Lapponian supergroup was covered with the Kumpu conglomerate-metasandstone-slate suite, occurring as Karelian, i.e. Sariolan-Jatulian, deposits. A few erosional remnants are capped with Svecofennian rocks 1.9 Ga old.The Lower Lapponian consists of basal arkose, the Möykkelmä greenstones, a cratonic quartzite-carbonate-schist suite and the Salla greenstone complex(es) preserving evidence of a lava plateau. The Salla bimodal metavolcanic rocks and the Middle Lapponian metasediments, which, at their thickest, constitute the Oraniemi arkose-slate-quartzite association (incl. redbeds), evidently indicate cratonic rifting that terminated with the growth of isolated lava fields of Fe-rich tholeiitic basalt. In the Upper Lapponian, euxinic-exhalative metasediments underlie the Sattasvaara, Sotkaselkä and Kummitsoiva komatiite complexes and the Kittilä greenstones, which are present as complicated but distinct eruption centres and contain a varying amount of ejecta and volcaniclastic greywacke-slate intercalations. The komatiite-dominant succession evidently represent mantle-activated rifting and the linear mantle upwelling.The Lapland greenstone belt and adjacent granulitic belt appear to constitute a paired metamorphic terrain, where the overthrusting of the granulites is explained by mutual motions of the distinct cratonic megablocks.

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Section: Regional Geological Settingmentioning

confidence: 72%

Section: Chronostratigraphic Evaluationmentioning

confidence: 92%

Section: Chronostratigraphic Evaluationmentioning

confidence: 92%

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The Lapland greenstone belt: Stratigraphic and depositional features in northern Finland

Saverikko¹

1987

Bull Geol Soc Finland

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“…According to the available evidence, most of the anorthositic, enderbitic and metapelitic rocks have a Palaeoproterozoic age range from about 2.0 to 1.9 Ga (Meriläinen, 1976;Bernard-Griffi ths et al, 1984;Huhma & Meriläinen, 1991;Sorjonen-Ward et al, 1994;Daly et al, 2001).…”

Section: Geological Settingmentioning

confidence: 99%

“…Also, the LGB was earlier thought to form part of the Archaean basement complex of the shield (i.e. Simonen, 1980) but later structural (Marker, 1988;Korja et al, 1996) and geochronological data showed that it is in most part a Palaeoproterozoic high-grade mobile belt surrounded by Archaean complexes (Meriläinen, 1976;Bernard-Griffi ths et al, 1984;Huhma & Meriläinen, 1991;Sorjonen-Ward et al, 1994;Tuisku & Huhma, 1998Daly et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Evolution of migmatitic granulite complexes: Implications from Lapland Granulite Belt, Part I: Metamorphic geology

Tuisku¹,

Mikkola²,

Huhma³

2006

Bull Geol Soc Finland

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The Palaeoproterozoic Lapland granulite belt was juxtaposed between Archaean and Proterozoic terrains in the NE part of the Fennoscandian Shield concurrently with the accretion of Svecofennian arc complexes at ~1.9 Ga. The belt consists mainly of aluminous migmatitic metagreywackes. Abundant noritic to enderbitic magmas were intruded concordantly into the metasediments and were probably an important heat source for metamorphism, which took place during the crystallization of the magmas. This is supported by structural and contact relations of metasediments and igneous rocks, and by the lack progressive metamorphic reaction textures in the igneous rock series. The peak of metamorphism took place above the dehydration melting temperature of the biotite-sillimanite-plagioclase-quartz assemblage at 750−850°C and 5−8.5 kbar which lead to formation of a restitic palaeosome and peraluminous granitic melt in metapelites. Subsequently, the rocks were decompressed and cooled below the wet melting temperature of pelitic rocks (650°C) under the stability fi eld of andalusite coexisting with potassium feldspar (2−3 kbar). Cooling was accompanied by the crystallization of the neosomes, often carrying aluminium-rich phases. Postmetamorphic duplexing of the LGB is clearly seen in the distribution of calculated PT conditions.

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Radiometric Ages (Rb-Sr, Sm-Nd, U-Pb) and REE Geochemistry of Archaean Granulite Gneisses from Eastern Hebei Province, China

Jahn

Zhang

1984

Archaean Geochemistry

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Isotopic data (UPb, RbSr, PbPb and SmNd) on mafic granulites from finnish lapland

Cited by 84 publications

References 17 publications

The Lapland greenstone belt: Stratigraphic and depositional features in northern Finland

The Lapland greenstone belt: Stratigraphic and depositional features in northern Finland

Evolution of migmatitic granulite complexes: Implications from Lapland Granulite Belt, Part I: Metamorphic geology

Radiometric Ages (Rb-Sr, Sm-Nd, U-Pb) and REE Geochemistry of Archaean Granulite Gneisses from Eastern Hebei Province, China

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