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Several orogenies have shaped the bedrock of southern Sweden. While mafic intrusions represent significant sources of information for reconstructing geodynamics and crustal evolution, the characterization of the various generations of such intrusions in Sweden remains limited. We report in situ zircon U–Pb ages and Hf isotope data from a Fe-Ti eclogite and a coronitic metagabbro from the Eastern Segment in southern Sweden. Crystallisation ages at 1683 ± 17 Ma of the eclogite suggest affiliation with the surrounding 1730–1660 Ma Transscandinavian Igneous Belt intrusions that dominate the Eastern Segment. Secondary zircon growth and Pb-loss in the eclogite sample at 1459 ± 44 Ma and the crystallisation of the metagabbro at 1431 ± 26 Ma overlap and are related to magmatic activity during the Hallandian orogeny. Zircon Hf isotope signatures with chondritic and sub-chondritic values at ~1683 Ma and ~1431 Ma, respectively, correspond to an enriched (or mildly depleted) source in line with a "Mixed Svecofennian Crustal Reservoir". These isotope signatures are more enriched than those in the surrounding gneisses. Zircon isotope data from the herein analysed zircon grains indicate that the eclogite and metagabbro had an enriched mafic source in the mid to lower crust, or within the subcontinental lithospheric mantle below Fennoscandia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Immobility of mafic w-r Sm-Nd and Lu-Hf during amphibolite facies metamorphism. • Despite Zr redistribution, Hf integrity stays intact. • Strengthens the feasibility of Sm-Nd and Lu-Hf analyses of (meta-)mafic whole-rocks. While whole-rock Lu-Hf isotope analysis remains one of the only ways to obtain initial Hf isotope signatures of old mafic rocks, Hf isotope analyses of more robust accessory zircon in intermediate to silicic rocks have largely replaced whole-rock analyses during the last decade. This has led to a discrepancy in the amount of existing data from mafic and felsic lithologies. However, especially in mafic, Si-poor rocks with a metamorphic imprint, Hf isotope data rely on whole-rock analysis since baddeleyite, commonly used for U-Pb age analyses of mafic rocks, is sensitive to alteration and metamorphism. Hence, to accurately evaluate the trace element and isotope signatures of altered mafic rocks, it is important to understand the mechanisms of element mobility during metamorphism. Here, we report whole-rock trace element compositions, Lu-Hf and Sm-Nd isotope data from variably deformed and metamorphosed samples of a mafic intrusion in southern Sweden, the Åker metabasite. These data suggest that trace elements were undisturbed on a whole-rock sample scale during deformation at upper amphibolite facies (at least 1000 MPa and 600 °C) metamorphism under hydrated conditions. Despite redistribution of Zr associated with the breakdown of baddeleyite and other igneous phases, the Åker metabasite has retained its chemical and isotopic integrity since igneous crystallisation at ca. 1565 Ma. This study demonstrates and strengthens the feasibility of whole-rock analyses of (meta-)mafic rocks for determining initial ε Nd and ε Hf values, despite deformation and metamorphism under hydrated amphibolite-grade metamorphic conditions. Testing the coherence of the calculated initial Nd and Hf isotope ratios by examining variably deformed and metamorphosed varieties of a rock in a single outcrop, could be used as a model for research on more complex Archean rocks. [ABSTRACT FROM AUTHOR]