Many studies in the central Swiss Alps have primarily focused on the Alpine and Variscan tectonometamorphic history recorded in distinct basement units and their Mesozoic cover. In order to unravel the provenance and pre-Mesozoic evolution of polymetamorphic lithologies, the present study combines classical geological techniques with geochemical, isotopic and high-resolution geochronological methods. The case study was carried out on the Lucomagno unit, which forms part of the Lower Penninic

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... ement in the Lepontine area and is located south of the Ultrahelvetic Gotthard unit and its Mesozoic cover, the Piora zone. Unlike the adjacent underlying Leventina gneiss and the overlying Simano nappe, which both contain substantial portions of I-type orthogneiss, the Lucomagno unit is dominated by para-and mixed gneisses. These gneisses contain abundant amphibolites mainly along the strongly deformed northern margin, whereas augengneisses and minor zones of S-type orthogneiss bodies are concentrated in the central part of the