Recurrent mesoproterozoic continental magmatism in South-Central Norway |
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| Authors: | Svend Pedersen Tom Andersen Jens Konnerup-Madsen William L Griffin |
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| Institution: | (1) Institute of Geography and Geology, University of Copenhagen, 1350 Copenhagen K, Denmark;(2) Department of Geology, University of Oslo, PO Box 1047, Blindern, 0316 Oslo, Norway;(3) GEMOC Key Centre, Department of Earth and Planet Sciences, Macquarie University, Sydney, NSW, 2109, Australia |
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| Abstract: | We report U–Pb dates and Lu–Hf isotope data, obtained by LAM-ICPMS, for zircons from metamorphic rocks of the Setesdalen valley,
situated in the Telemark block south of the classic Telemark region of southern Norway. The samples include infracrustal rocks
from the metamorphic basement, metaigneous rocks and metasediments from the Byglandsfjorden supracrustal cover sequence, and
metaigneous rocks which intruded the whole succession. The main crustal evolution took place from 1,550–1,020 Ma, beginning
with the emplacement of juvenile tonalitic melts; the contribution of older crustal material increased with time. Around 1,320 Ma,
further addition of juvenile material occurred, involving both mafic and felsic melts, metamorphism and deformation. Acid
magmas with high FeO*/MgO were intruded at 1,215 Ma, coinciding with underplating elsewhere in South Norway. The period starting
at 1,215 Ma is represented by supracrustal rocks, principally metarhyolites with minor mafic material and immature sediments
of the Byglandsfjorden Group. The crust generation processes ended with the intrusion of diorites and granodiorites at 1,030 Ma,
late in the Sveconorwegian orogeny. Regional processes of metamorphism and deformation (around 1,290 and 1,000 Ma) can be
related to the assembly of Rodinia.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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| Keywords: | Mesoproterozoic Sveconorwegian orogeny U– Pb Lu– Hf Telemark Norway |
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