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GEOREF RECORD

Polyphase (1.6-1.5 and 1.1-1.0 Ga) deformation and metamorphism of Proterozoic (1.7-1.1 Ga) continental crust, Idefjorden Terrane, Sveconorwegian Orogen

Ulf Bergstrom, Michael B. Stephens and Carl-Henric Wahlgren
Polyphase (1.6-1.5 and 1.1-1.0 Ga) deformation and metamorphism of Proterozoic (1.7-1.1 Ga) continental crust, Idefjorden Terrane, Sveconorwegian Orogen (in Sweden; lithotectonic framework, tectonic evolution and mineral resources, M. B. Stephens (editor) and J. Bergman Weihed (editor))
Memoirs of the Geological Society of London (2020) 50: 397-434

Abstract

Crust generated during an accretionary orogeny at 1.66-1.52 Ga (Gothian), and later during crustal extension at c. 1.51-1.49, c. 1.46, c. 1.34-1.30 Ga and after c. 1.33 Ga, dominate the Idefjorden terrane. Metamorphism under greenschist to, locally, high-pressure granulite facies, emplacement of syn-orogenic pegmatite and granite, and polyphase deformation followed at 1.05-1.02 Ga (Agder tectonothermal phase, Sveconorwegian orogeny). Sinistral transpressive deformation, including foreland-directed thrusting, preceded top-to-the-west movement and large-scale open folding along north-south axial trends during the younger orogeny. Crustal extension with emplacement of dolerite and lamprophyre dykes, norite-anorthosite, and a batholithic granite took place at c. 0.95-0.92 Ga (Dalane phase, Sveconorwegian orogeny). Ductile shear zones divide the Idefjorden terrane into segments distinguished by the character of the Gothian crustal component. Orthogneisses with c. 1.66 and c. 1.63-1.59 Ga protoliths occur in the Median segment; c. 1.59-1.52 Ga gneissic intrusive rocks and 1.6 Ga paragneisses with relicts of Gothian deformation and migmatization at c. 1.59 Ga and at c. 1.56-1.55 Ga occur in the Western segment. Mineral resources include stratabound Cu-Fe sulphides hosted by sandstone deposited after c. 1.33 Ga, and polymetallic quartz vein mineralization locally containing Au.


ISSN: 0435-4052
Coden: GSLMAD
Serial Title: Memoirs of the Geological Society of London
Serial Volume: 50
Title: Polyphase (1.6-1.5 and 1.1-1.0 Ga) deformation and metamorphism of Proterozoic (1.7-1.1 Ga) continental crust, Idefjorden Terrane, Sveconorwegian Orogen
Title: Sweden; lithotectonic framework, tectonic evolution and mineral resources
Author(s): Bergstrom, UlfStephens, Michael B.Wahlgren, Carl-Henric
Author(s): Stephens, M. B.editor
Author(s): Bergman Weihed, J.editor
Affiliation: Swedish Geological Survey, Uppsala, Sweden
Affiliation: Lulea University of Technology, Lulea, Sweden
Pages: 397-434
Published: 2020
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 150
Accession Number: 2020-042959
Categories: Solid-earth geophysicsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, sketch maps
N56°34'60" - N59°30'00", E10°45'00" - E14°46'00"
Secondary Affiliation: Lulea University of Technology, SWE, Sweden
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 2020
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