Anders Scherstén
Universitetslektor
Zircon U-Pb and Hf - isotopes from the eastern part of the Sveconorwegian Orogen, SW Sweden : Implications for the growth of Fennoscandia
Författare
Summary, in English
Current models for the growth of Fennoscandia, including the eastern part of the Sveconorwegian Province, are largely based on U-Pb data and do not discriminate between juvenile and reworked crust. Here we present new combined U-Pb and Hf isotopic data, from the Eastern Segment and the Idefjorden terrane of the Sveconorwegian Province, and suggest a revised model of crustal growth. Most of the crystalline basement in this part of the shield formed by mixing of a 2.1-1.9 Ga juvenile component and Archaean crust. Archaean reworking decreases between 1.9 and 1.7 Ga and a mixed Svecofennian crustal reservoir is generated. Succeeding magmatism between 1.7 and 1.4 Ga indicates reworking of this reservoir with little or no crust generation. At c. 1.2 Ga, an influx of juvenile magma is recorded by granite to quartz-syenite magmatism with mildly depleted (εHf 1.18 Ga of c. 3) signatures. The amount of recycled crust in the 1.9- 1.7 Ga arc system is in contrast to previously proposed models for the growth of the southwestern part of the Fennoscandian Shield. This model agrees with long-term subduction along the western margin of Fennoscandia, but suggests substantial reworking of existing crust and decreasing amounts of <1.9 Ga crustal growth.
Avdelning/ar
- Berggrundsgeologi
Publiceringsår
2015-05-24
Språk
Engelska
Sidor
281-303
Publikation/Tidskrift/Serie
Geological Society Special Publication
Volym
389
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Geological Society of London
Ämne
- Geology
Aktiv
Published
ISBN/ISSN/Övrigt
- ISSN: 0305-8719