Zircon and monazite reveal late Cambrian/early Ordovician partial melting of the Central Seve Nappe Complex, Scandinavian Caledonides

Abstract The Seve Nappe Complex (SNC) comprises continental rocks of Baltica that were subducted and exhumed during the Caledonian orogeny prior to collision with Laurentia. tectonic history central SNC is investigated by applying in-situ zircon monazite (Th-)U–Pb geochronology trace element analysis (ultra-)high pressure (UHP) paragneisses in Avardo Marsfjället gneisses. Zircons Gneiss exposed at Sippmikk creek exhibit xenocrystic cores metamorphic rims. Cores show typical igneous REE profiles affected partial Pb-loss. rims have flat HREE are interpreted crystallized 482.5 ± 3.7 Ma biotite-dehydration melting peritectic garnet growth. Monazites paragneiss chemically homogeneous record metamorphism 420.6 2.0 Ma. In near Kittelfjäll, monazites complex zoning enveloped mantles 481.6 2.1 Ma, possibly resorption. provide a dispersion dates formed melt-driven dissolution-reprecipitation pre-existing until 463.1 1.8 Depletion Y, HREE, U compared Altogether, gneisses evidence late Cambrian/early Ordovician (possibly (U)HP conditions), Middle metamorphism, Silurian tectonism. These results indicate underwent south-to-north oblique subduction Cambrian time, followed progressive north-to-south exhumation crustal levels collision.