Crustal growth and reworking during Lapland-Kola orogeny in northern Fennoscandia: U-Pb and Lu-Hf data from the Nattanen and Litsa-Aragub-type granites

In this paper we present new zircon U-Pb, Lu-Hf and REE data for Palaeoproterozoic intrusions (Nattanen- and Litsa-Aragub-type granites) of the Fennoscandian shield, to obtain a more detailed understanding of their petrogenesis. The intrusions form a chemically homogenous group of SiO₂-rich A-type, post-kinematic granites that were emplaced between 1.79 and 1.76Ga. The Hf isotopes indicate that the source was dominated by an Archaean crustal component although a mantle contribution cannot be ruled out. The isotopic data further constrain the evolution of the Archaean and Palaeoproterozoic crust and the assembly of the Nuna (Columbia) supercontinent. The Nattanen- and Litsa-Aragub-type granites are part of a voluminous phase of granitoid magmatism in Fennoscandia at 1.8-1.75Ga, reflecting large-scale processes at the margin of the Nuna supercontinent.