Relationships between granite-gneiss terrains, greenstone belts and granulite belts in the archean crust of Lapland (Fennoscandia)

Barbey, Pierre; Convert, J.; Martin, Hervé; Moreau, B.; Capdevila, Ramon Buxó i; Hameurt, Jean

doi:10.1007/bf02104639

Cited by 25 publications

(12 citation statements)

References 7 publications

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“…2). This narrow belt is essentially a highly strained, ductile shear zone, akin to a mélange, consisting of migmatised amphibolite-facies basic gneisses containing numerous lenses and fragments of gabbroic, anorthositic and ultramafic rocks (Barbey et al, 1980;Marker, 1985). On the aeromagnetic data, lineaments in the TB are clearly discernible.…”

Section: Resultsmentioning

confidence: 99%

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

Nasuti¹,

Roberts²,

Dumais³

et al. 2016

NJG

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New high-resolution aeromagnetic data from the Caledonides and Archaean-Palaeoproterozoic crystalline basement of Finnmark and North Troms derived from surveys conducted as part of NGU's MINN programme provide spectacular and confirmatory evidence for the continuation of diverse, Precambrian greenstone belts and granulite terranes beneath the magnetically transparent Caledonian nappes. Complementary airborne radiometric data collected in the same survey contribute to the analytical process and to an evaluation of the mineral potential in the area. Some parts of existing data have also been reprocessed using new techniques and software to reach the same level as the newly acquired data. The new compiled data provide images of the magnetic field at sufficiently high resolution to allow us to examine finer details of the bedrock geology. One of the principal outcomes of the analysis is a picture of the detailed structural fabric of the region provided by images of tilt derivatives of the magnetic field that enhance anomalies. This fabric is an important framework for developing exploration strategies. Patterns and other characteristics of the magnetic field have been used to revise positions of some geological boundaries, especially in poorly exposed areas, and delineate specific domains within northern Norway. Radiometric data have been used to supplement the magnetic interpretations in some cases. In general, there is a good correlation between the radiometric data and magnetic anomaly maps which can be utilised to re-evaluate the geological boundaries. Several such features of interest are discussed. As an example, NW-SE-trending, fault-bounded terranes or belts which extend from Finnmark and Troms through northern Finland, Sweden and Russia can be easily followed on the high-resolution data. In this contribution, all the main geological terranes from the Archaean-Palaeoproterozoic belt to the Caledonian nappes in northern Norway will be discussed in relation to their magnetic patterns and radiometric anomalies.

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Section: Resultsmentioning

confidence: 99%

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

Nasuti¹,

Roberts²,

Dumais³

et al. 2016

NJG

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“…For example, the quartzofeldspar-gneiss-quartzite-mica-gneiss suite at the base (Meriläinen 1976) resembles the Lower Lapponian metasediments and, in the southwestern margin, it is accompanied by a bimodal metavolcanic complex showing signs of crustal contamination (Barbey et al 1984). This volcanic-sedimentary gneiss assemblage underlies the khondalitic suite of arkosic and pelitic metasediments (Meriläinen 1976;Barbey et al 1980) laid down in sediment gravity flow-dominated conditions (Barbey et al 1984). 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.…”

Section: Regional Geological Settingmentioning

confidence: 98%

“…The primary strata were a thick cyclic pile of arkosic and pelitic sediments with subordinate volcaniclastic greywackes, felsic volcanics, quartzites, graphitic and calc-silicatic sediments and tholeiitic basalts of massive or banded texture (Barbey et al 1980(Barbey et al , 1984Suslova (1976) also reports pyroxene peridotitic komatiites in the Soviet Union. Orthogneisses or gneisses of unclear nature may derive from calc-alkaline basalts to rhyolites with abundant andesites (Barbey et al 1980;Hörmann et al 1980). The igneous rocks are chemically similar to those found in the l ie.…”

Section: Regional Geological Settingmentioning

confidence: 99%

“…The granulite complex and the Lapland greenstone belt pass into each other despite the overthrust of the granulites upon the greenstones (Meriläinen 1976). The granulites have a bulk sedimentary parentage (Barbey et al 1980(Barbey et al , 1982(Barbey et al , 1984Hörmann et al 1980) although metavolcanic rocks prevail in Soviet territory (Suslova 1976). The primary strata were a thick cyclic pile of arkosic and pelitic sediments with subordinate volcaniclastic greywackes, felsic volcanics, quartzites, graphitic and calc-silicatic sediments and tholeiitic basalts of massive or banded texture (Barbey et al 1980(Barbey et al , 1984Suslova (1976) also reports pyroxene peridotitic komatiites in the Soviet Union.…”

Section: Regional Geological Settingmentioning

confidence: 99%

“…The granulites have a bulk sedimentary parentage (Barbey et al 1980(Barbey et al , 1982(Barbey et al , 1984Hörmann et al 1980) although metavolcanic rocks prevail in Soviet territory (Suslova 1976). The primary strata were a thick cyclic pile of arkosic and pelitic sediments with subordinate volcaniclastic greywackes, felsic volcanics, quartzites, graphitic and calc-silicatic sediments and tholeiitic basalts of massive or banded texture (Barbey et al 1980(Barbey et al , 1984Suslova (1976) also reports pyroxene peridotitic komatiites in the Soviet Union. Orthogneisses or gneisses of unclear nature may derive from calc-alkaline basalts to rhyolites with abundant andesites (Barbey et al 1980;Hörmann et al 1980).…”

Section: Regional Geological Settingmentioning

confidence: 99%

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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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The Granulite Belt of Lapland

Barbey¹,

Raith

1990

Granulites and Crustal Evolution

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Relationships between granite-gneiss terrains, greenstone belts and granulite belts in the archean crust of Lapland (Fennoscandia)

Cited by 25 publications

References 7 publications

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

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

The Granulite Belt of Lapland

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