Geotectonic Significance of the Metabasites of the Kinzigitic Series, Ivrea-Verbano Zone (Western Italian Alps)

Geochemical investigations have been carried out on the metabasites of the Ivrea-Verbano Zone (NW-Italy). The Ivrea-Verbano Zone is commonly considered to be a section through the lower continental crust. It is constituted by a steeply dipping sequence of metamorphic rocks (Kinzigitic Series), intruded by a mafic-ultramafic complex. The metabasites of the Kinzigitic Series have a meta-igneous origin, Their protoliths show tholeiilic affinity in the NW and central part of the zone and alkali affinity in the SE. This fact together with the rock associations suggests that a variation of the paleogeographic environment from NW to SE occurs in the Ivrea-Verbano Zone.