Tectonic Processes and Crustal Evolution in the Sveconorwegian Orogen

The Sveconorwegian Orogen, exposed across southern Norway and parts of southwest Sweden, represents a Mesoproterozoic mountain‐building event active between ca 1,140 and 920 Ma. This orogen comprises a collage of discrete lithotectonic units that record contrasting metamorphic conditions, from ultrahigh‐temperature domains in the west to high‐pressure terranes nearer the foreland. Initial assembly involved accretionary processes at an active continental margin, sustained by mafic underplating and repeated pulses of crustal melting that generated voluminous granitoid suites. A major strike‐slip structure—the Mylonite Zone—later accommodated lateral transport of allochthonous crustal fragments, while synchronous delamination and foundering of dense lithospheric mantle contributed to thermal anomalies and widespread high‐temperature metamorphism. Following peak contractional deformation, the orogen underwent episodic extension, marked by low‐angle detachment faults and rapid exhumation of deep‐seated rocks. The resulting architecture records a full Wilson‐cycle analogue, from subduction‐driven orogenesis to orogenic collapse. Beyond its regional importance for reconstruction of Rodinia, the Sveconorwegian belt offers a template for understanding crustal growth, resource formation (including rare‐element pegmatites), and the evolution of plate‐boundary processes over geological time.

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Tectonic Processes and Crustal Evolution in the Sveconorwegian Orogen publication trend

The graph below shows the total number of articles in tectonic processes and crustal evolution in the sveconorwegian orogen across all publications each year (not limited to Nature Index journals).

Technical terms

Lithotectonic unit: A crustal block distinguished by its unique lithology and tectonometamorphic history.

U–Pb geochronology: Radiometric dating method that utilises the decay of uranium isotopes to lead in zircon minerals to determine crystallisation ages.

40Ar/39Ar dating: A step‐heating technique that measures argon isotopes in micas and amphiboles to constrain cooling and deformation ages.

Detachment fault: A low‐angle normal fault that accommodates large‐scale extension and exhumation of deep crustal rocks.

Natural remanent magnetisation: The permanent magnetic signature acquired by rocks as they cool through the Curie temperature in Earth’s magnetic field.

References

1. The Sveconorwegian orogeny – Reamalgamation of the fragmented southwestern margin of Fennoscandia. Precambrian Research (2020).
2. Tectonomagmatic evolution of the Sveconorwegian orogen recorded in the chemical and isotopic compositions of 1070–920 Ma granitoids. Precambrian Research (2020).
3. Subduction and loss of continental crust during the Mesoproterozoic Sveconorwegian Orogeny. Precambrian Research (2024).
4. Multi-isotope tracing of the 1.3–0.9 Ga evolution of Fennoscandia; crustal growth during the Sveconorwegian orogeny. Gondwana Research (2021).
5. 40Ar/39Ar constraints on the tectonic evolution of the central part of the Mesoproterozoic Sveconorwegian orogen. Journal of Structural Geology (2023).
6. Paleomagnetism and 40Ar/39Ar geochronology of Meso-Neoproterozoic rocks from southwest Norway. Implications for magnetic remanence ages and the paleogeography of Baltica in a Rodinia supercontinent context. Precambrian Research (2022).
7. Geochronological constraints for a two-stage history of the Sveconorwegian rare-element pegmatite province formation. Precambrian Research (2023).